battery question
mikeandeb
and then have several strings of them in parallel to increase the amp hour
capacity? Isn't it more economical to use a few 12 volt 750ah deep cycle
marine batteries in parallel to get the desired amount of amp hour storage?
I can't see why you would use two 6 volt batteries instead of using 1 12
volt battery. And connect as many as you need in parallel to get the amp
hours you need.
Pete Prossen
than even the best marine/RV batteries.
They have lots more room at the bottom of the cells to accumulate debris
before a short circuit kills the cell. Also, the plates are more thicker
and more rugged.
"mikeandeb" <mike...@earthlink.net> wrote in message
news:5m2i6.1106$Vd.1...@newsread1.prod.itd.earthlink.net...
Graig Pearen
battery. Golf cart or forklift (traction) batteries are true deep discharge batteries and will last
about 10 times as long. Since the price is roughly the same per amp-hour, the golf cart batteries
are 10 times as cost effective!
Graig
"mikeandeb" <mike...@earthlink.net> wrote:
--
Remove the "nospam." from my e-mail address when replying.
Sylvan Butler
> Why do people use many 6 volt golf cart batteries in series to get 12 volts
> and then have several strings of them in parallel to increase the amp hour
> capacity? Isn't it more economical to use a few 12 volt 750ah deep cycle
No. Those are NOT 750ah batteries. A 750ah 12v battery would weigh
about 450 pounds.
> I can't see why you would use two 6 volt batteries instead of using 1 12
> volt battery. And connect as many as you need in parallel to get the amp
> hours you need.
It is better for batteries to be in series rather than parallel. The
more parallel cells you have, the more likely they are to become
unbalanced. I normally recommend staying below a maximum of 5 parallel
strands. After that you need to get higher capacity cells rather than
simply add more in parallel.
sdb
--
More guns means less crime. ISBN:0-226-49363-6
***
Watch out for munged e-mail address.
User should be sylvandb1 and host is at bigfoot.com
Do NOT send me unsolicited commercial e-mail (UCE)!
George L Ghio
One string of 6 - 2 Volt 770Amp hour batteries US $1263.00 (converted
from $2615.00 Aust.) (8 year warranty)
How much for the same storage in golf cart batteries? How many strings?
George
In article <5m2i6.1106$Vd.1...@newsread1.prod.itd.earthlink.net>,
Sylvan Butler
> One string of 6 - 2 Volt 770Amp hour batteries US $1263.00 (converted
> from $2615.00 Aust.) (8 year warranty)
So that would be 12v, 770ah.
> How much for the same storage in golf cart batteries? How many strings?
The "standard" Trojan T105 is 6v 220ah and sells for (typically) about
$70US. That would be 6 batts in three strings at 660ah for $420US, or
8 batts in four strings at 880ah for $560US.
I'd say that less than 1/2 the price is quite a savings.
Plus, I bought my "trojan equivalent" for $47US/batt (including $5/batt
recycling fee) with a 4yr full replacement warranty and an additional 4
years prorated about 20%/year from a local battery retailer/wholesaler.
That means I got my 8 batts for $376US or less than 1/3 your price. And
mine are in a 48v backup power system, so I have only one string.
The only issue then, becomes number of cells. With 8-6v batts you have
to water 24 cells, where your pack only needs to water 6 cells. Luckily
my batts only need water about every six months.
George L Ghio
Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
> On Wed, 14 Feb 2001 22:18:18 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
> > One string of 6 - 2 Volt 770Amp hour batteries US $1263.00 (converted
> > from $2615.00 Aust.) (8 year warranty)
>
> So that would be 12v, 770ah.
>
> > How much for the same storage in golf cart batteries? How many strings?
>
> The "standard" Trojan T105 is 6v 220ah and sells for (typically) about
> $70US. That would be 6 batts in three strings at 660ah for $420US, or
> 8 batts in four strings at 880ah for $560US.
>
> I'd say that less than 1/2 the price is quite a savings.
>
> Plus, I bought my "trojan equivalent" for $47US/batt (including $5/batt
> recycling fee) with a 4yr full replacement warranty and an additional 4
> years prorated about 20%/year from a local battery retailer/wholesaler.
> That means I got my 8 batts for $376US or less than 1/3 your price. And
> mine are in a 48v backup power system, so I have only one string.
>
> The only issue then, becomes number of cells. With 8-6v batts you have
> to water 24 cells, where your pack only needs to water 6 cells. Luckily
> my batts only need water about every six months.
What every 6 months? So you will replace your batteries in 8 years. I
would not expect to replace mine in the next 16 years (expected life by
manufacturer) but am aiming for at least 20 years.
I have seen the trojan batteries have even sold some. Would not own
them.
George
George L Ghio
Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
> On Wed, 14 Feb 2001 22:18:18 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
> > One string of 6 - 2 Volt 770Amp hour batteries US $1263.00 (converted
> > from $2615.00 Aust.) (8 year warranty)
>
> So that would be 12v, 770ah.
>
> > How much for the same storage in golf cart batteries? How many strings?
>
> The "standard" Trojan T105 is 6v 220ah and sells for (typically) about
> $70US. That would be 6 batts in three strings at 660ah for $420US, or
> 8 batts in four strings at 880ah for $560US.
>
> I'd say that less than 1/2 the price is quite a savings.
>
> Plus, I bought my "trojan equivalent" for $47US/batt (including $5/batt
> recycling fee) with a 4yr full replacement warranty and an additional 4
> years prorated about 20%/year from a local battery retailer/wholesaler.
> That means I got my 8 batts for $376US or less than 1/3 your price. And
> mine are in a 48v backup power system, so I have only one string.
Put those batteries in a solar power system and you would be lucky to
get the 4 years.
Nick Pine
>...I would not expect to replace mine in the next 16 years (expected
>life by manufacturer) but am aiming for at least 20 years.
Care to explain this in more detail?
Nick
George L Ghio
manufacturer.
I look after my batteries.
-20% discharge/day (average 12%)
Reasonably constant temp.
Use of good charge controller. (PL40 Digital Smart reg)
Proper system design & sizing. No guess work.
Regular maint.
Batteries are the ones used by Telecom. Telecom does not buy golf cart
batteries.
A friend of mine replaced his old Telecom batteries this year. He
bought them as second hand (ten years old, dated) and used them for
another 16 years. That is 26 years all together. Maintenance as above.
George
In article <96gilm$j...@ufo.ee.vill.edu>, Nick Pine
Nick Pine
>16 years is the life expectancy of the batteries as given by the
>manufacturer.
Care to explain this in more detail?
>-20% discharge/day (average 12%)
Is that what the manufacturer uses for the 16 year spec?
>A friend of mine replaced his old Telecom batteries this year. He
>bought them as second hand (ten years old, dated) and used them for
>another 16 years. That is 26 years all together...
Perhaps they were never deliberately discharged at all,
in telecom service...
Nick
wmbjk
"Nick Pine" <ni...@ufo.ee.vill.edu> wrote in message
news:96lmlh$k...@ufo.ee.vill.edu...
Can't comment on George's batteries. But designing systems with 10 or 15
year expected battery life should not be difficult. Hup guarantees 2100 deep
cycles with ten year warranty. Rolls claims 3300 cycles to 50% DOD, also
with a ten year warranty. And I saw one advertising 4000 cycles, might have
been IBE. I take these ads with a grain of salt. But such batteries have
been in service in electric forklifts for a long time, and do deliver that
kind of performance. One could argue that in order to plan 15 years of
service, that you have to "oversize" the battery capacity. But that's
usually the case anyway.
Wayne
George L Ghio
<ni...@ufo.ee.vill.edu> wrote:
> George L Ghio <gh...@netconnect.com.au> wrote:
>
> >16 years is the life expectancy of the batteries as given by the
> >manufacturer.
>
> Care to explain this in more detail?
>
> >-20% discharge/day (average 12%)
>
> Is that what the manufacturer uses for the 16 year spec?
Pretty much. This also applies to most other deep cycle batteries.
>
> >A friend of mine replaced his old Telecom batteries this year. He
> >bought them as second hand (ten years old, dated) and used them for
> >another 16 years. That is 26 years all together...
>
> Perhaps they were never deliberately discharged at all,
> in telecom service...
Perhaps. Then again they could have been discharged to 50% daily.
You don't buy a drill when you need a saw. Batteries are built to do
different jobs. i.e. the alloy used in the plates is a good example.
Also the sediment gap and reserve of electrolyte make a difference as
well as out right physical size. At 55 Kg each cell (726 Lb for a set
of 6) you get a lot of lead and electrolyte to play with.
George
Nick Pine
>> >16 years is the life expectancy of the batteries as given by the
>> >manufacturer.
>> Care to explain this in more detail?
>> >-20% discharge/day (average 12%)
>> Is that what the manufacturer uses for the 16 year spec?
>Pretty much...
Who makes them and what do they cost and what do you mean by "pretty much"?
Is the 16 year life expectancy guaranteed? Are they rated for storage life
in total kWh, like Trojans?
Nick
George L Ghio
3AS190, AS390, AS580, AS620, AS770, AS920, AS1100
12-14 years life @ daily D.O.D 20%
Pretty Much means I run daily D.O.D. of 12%
I could have used the AS620 but that would have ment a daily D.O.D. of
around 18.5% for my system.
The AS770 $2340.00 AU
8 Year warranty. I am suprised at this as they really have no control
over the use/abuse of their product.
What storage life. You buy them and put them into service.
Nobody guarantees batteries, Warranty is it, subject to conditions.
The people who use this sort of equipment are serious users of solar
energy, not weekend greenies.
These news groups are the only place I have met people that "play" with
solar. (and complain about the price of their chosen hobby)
George
In article <96mne0$k...@ufo.ee.vill.edu>, Nick Pine
David Kunz
...
: Can't comment on George's batteries. But designing systems with 10
: guarantees 2100 deep cycles with ten year warranty. Rolls claims
: 3300 cycles to 50% DOD, also with a ten year warranty. And I saw
: one advertising 4000 cycles, might have been IBE. I take these ads
: with a grain of salt. But such batteries have been in service in
: electric forklifts for a long time, and do deliver that kind of
: performance. One could argue that in order to plan 15 years of
: service, that you have to "oversize" the battery capacity. But
: that's usually the case anyway.
Isn't "oversizing" along the same lines as buying it now or later, but
still buying the same final number of batteries over the long run?
REMEMBER, the bottom line is that if you take care of your batteries,
their life is really measured in total amp-hours output -- not years.
In fact, I seem to remember that batteries provide the most overall
capacity (total amps out over their lifetimes) when discharged to 50%
or so. SO, if you oversize and only discharge to 20%, you may appear
to get longer life (this bank of batteries will last longer because it
will take longer to reach their total amp-hours output), but you will
be buying more batteries each time your replace 'em -- and in the end
you will buy more batteries over the life of your system because you
haven't used them in the discharge ranges where they last the longest.
--
David Kunz
Operator error. Replace operator and strike any key to continue...
Nick Pine
>> >> >16 years is the life expectancy of the batteries as given by the
>> >> >manufacturer.
>12-14 years life @ daily D.O.D 20%
Works for large values of 12...
>8 Year warranty...
Or 8...
>The AS770 $2340.00 AU
What's that in greenbacks, for how many volts and amp-hours?
Nick
George Estep
No, the main reason to oversize you battery is to obtain the best
performance from you PV (or wind) system. Even with batteries where the
life is not greatly affected by depth-of-discharge, as lead-acid batteries
are, you would want to to have at least four days of battery storage to
effectively average your peaks and minimums. That equates to less than a
25% depth-of-discharge per day, since you do collect some power while it is
being used, thus not storing it. One to two weeks of storage will give you
the best performance from your energy harvester (PV or wind), but most
systems are not designed with this much storage.
Regards,
George Estep
"David Kunz" <da...@clark.net> wrote in message
news:eXNj6.448164$w61.5...@dfw-read.news.verio.net...
George L Ghio
<ni...@ufo.ee.vill.edu> wrote:
12V - 770Ah - $1263.60 US
George
George L Ghio
The batteries are correctly sized to the system requirments.
20% DOD or less for longest service.
At C120 20% dod gives 5 days autonomy. After 5 days batteries are 80%
discharged.
I design to needs.
If you design to minimum needs you get minimum service.
If you design to average needs you get average service.
First step in design, define your needs.
George
In article <t90gqq7...@corp.supernews.com>, George Estep
wmbjk
"David Kunz" <da...@clark.net> wrote in message
news:eXNj6.448164$w61.5...@dfw-read.news.verio.net...
I think you're sorta' right about the "buy now or pay later thing". But you
appear to be recommending that people design systems with a normal
battery-discharge cycle of 50%. That might pay (although I doubt it) if th
sources and loads were steady and predictable, and the battery storage
temperature was constant. In home systems though, generally none of that is
true. Another problem, in our system for example, once the batteries are at
about 60% (of fully charged), we run the risk of nuisance inverter shut
downs (on our not-so-smart Exeltech) caused by temporary low voltage when
large motors are started. I suppose we could automate the system to whatever
degree necessary to prevent the problem, in order to make use of a smaller
battery bank. But we'd have to save enough to cover the pain of swapping
batteries sooner.
Even if they were half the size, they'd still be 1000 pounds of schlepping.
Your theory is contrary to the usual recommendation. Do you have any numbers
or cites to back it up? The only benefits I've heard of designing systems
with smallish, or lower cost batteries, are these....1. lower up-front cost
2. A smaller loss if the batteries are severely abused during the learning
process. :-)
Wayne
Nick Pine
>> >> >> >16 years is the life expectancy of the batteries as given by the
>> >> >> >manufacturer.
>> >12-14 years life @ daily D.O.D 20%
>> Works for large values of 12...
>> >8 Year warranty...
>12V - 770Ah - $1263.60 US
So we might figure the storage cost at $1263/(8x365x0.2x12x770/1000)
= 23.4 cents/kWh, at an interest rate of 0% per year...
Nick
Nick Pine
>>12V - 770Ah - $1263.60 US
>...we might figure the storage cost at $1263/(8x365x0.2x12x770/1000)
>= 23.4 cents/kWh, at an interest rate of 0% per year...
Or maybe 20% more, allowing for battery and inverter inefficiencies.
Nick
David Kunz
...
: > Isn't "oversizing" along the same lines as buying it now or
: > the long run?
: I think you're sorta' right about the "buy now or pay later thing".
: But you appear to be recommending that people design systems with a
: normal battery-discharge cycle of 50%. That might pay (although I
: doubt it) if th sources and loads were steady and predictable, and
: the battery storage temperature was constant. In home systems
: though, generally none of that is true.
My major point here was really that the culture in this news group is
to tout that good battery treatment is to only discharge to 20% or so
when battery manufacturers seem to disagree with this (been discussed
before -- check deja-news for sources of information including Bogart
Engineering (Trimetric meter) and a couple of battery company longvity
information sources).
: Another problem, in our
: system for example, once the batteries are at about 60% (of fully
: charged), we run the risk of nuisance inverter shut downs (on our
: not-so-smart Exeltech) caused by temporary low voltage when large
: motors are started. I suppose we could automate the system to
...
I've had no problems starting my well pump (3/4 hp) from a DR3624
attached to a T240 (120v->240v transformer) when the batteries are at
20% of full charge (8 ea of T104's configured for 24v). The draw to
start the pump is over 350 amps from the batteries (34 amps at 240v).
But, I'm connected with 4/0 even though my average draw would tend to
support much smaller cables. I went with 4/0 for exactly this reason
(based on a very sage recommendation from the solar engineer that I
was working with when I initially put my system into service). YMMV.
A factor here may be (also been discussed before) the fact that if you
don't go through a few full cycles to 20% of full charge (80% DOD)
when you initially install the batteries, the batteries will not
produce their full capacity when needed. This has also been discussed
here. I initially got this from the solar engineer (again) and had it
confirmed from other sources through battery companies.
BUT, I agree with the implicit design assumption that discharging to
50% regularly implies only a 2 day "reserve" when there's bad charging
conditions -- and 2 days is not close to enough. I've been wondering
/ background-thinking about a system that uses 2 or 3 smaller banks
and ping-pongs between them to get better control over DOD and have
better reserve capacity without using only a small portion of their
capacity most of the time. This would also permit adding a set of new
batteries to my system to increase my overall reserve without worrying
about the fact that they'd be totally mismatched with the set I've
been using. In normal use, I'd switch on a weekly basis. In bad
charging conditions, I switch at about 50% DOD. And round-robin after
that as they each go towards 20%.
And, *for me*, I'd rather have the cash outlay for 1/2 of my batteries
and only move 1/2 at a time twice as often than replace the whole
thing at 2x the kerchunk! (hurts my back just thinking about it :)).
Nick Pine
>...A factor here may be (also been discussed before) the fact that if you
>don't go through a few full cycles to 20% of full charge (80% DOD)
>when you initially install the batteries, the batteries will not
>produce their full capacity when needed. This has also been discussed
>here. I initially got this from the solar engineer (again) and had it
>confirmed from other sources through battery companies.
More kargo kult knowledge? Sounds like a nicad vs lead-acid problem.
Nick
George L Ghio
battery life is given at 6-8 yearsat 50% DOD and 9-12 years at 25% DOD.
So perhaps your supplier feels that it is moraly wrong to allow suckers
to keep their money:-}
More likly is that he is using figures for ups or golf carts and has no
idea about solar power useage.
there is no oversizing my system is well balanced and correctly sized
from the energy required to the number of panels needed.
Do you run a full time system or is youe experiance all hearsay.
George
In article <Bv6k6.454286$w61.5...@dfw-read.news.verio.net>, David
George L Ghio
<ni...@ufo.ee.vill.edu> wrote:
So we might figure the storage cost at $1263/(14x365x0.2x12x770/1000)
= 13.3 cents/kWh, fixed rate for 14 + years
Or we might figure the storage cost at $1263/(20x365x0.2x12x770/1000)
= 9.3 cents/kWh, fixed rate for 20 + years
And how much intrest does you electricty supplier pay you on the money
you pay for your energy.
George
George Estep
You just proved David's point.
George Estep
"George L Ghio" <gh...@netconnect.com.au> wrote in message
news:190220012223438992%gh...@netconnect.com.au...
George Estep
It appears that you are agreeing with me vehemently!
Regards,
George Estep
"George L Ghio" <gh...@netconnect.com.au> wrote in message
news:190220010937250378%gh...@netconnect.com.au...
wmbjk
> ...
> I've had no problems starting my well pump (3/4 hp) from a DR3624
> attached to a T240 (120v->240v transformer) when the batteries are at
> 20% of full charge (8 ea of T104's configured for 24v
When I said "large" motors, I was referring to a 4 hp (no, not Sears hp) air
compressor, a smaller compressor, tablesaw, radial arm saw, and thickness
planer, all around 2 hp. The temporary voltage drop doesn't fool the
inverters (4024s) that these motors are running off of, but it can trip up
the Exeltech that our electronic stuff is hooked to. At 1/2 hp, our well
pump is a pip squeak. :-)
Even if temporary voltage drop wasn't a problem, I wouldn't try a smaller
battery bank on our system. If I could afford it, I'd make it twice as big.
Wayne
Nick Pine
>> >> >8 Year warranty... 12V - 770Ah - $1263.60 US
>> So we might figure the storage cost at $1263/(8x365x0.2x12x770/1000)
>> = 23.4 cents/kWh, at an interest rate of 0% per year...
>So we might figure the storage cost at $1263/(14x365x0.2x12x770/1000)
>= 13.3 cents/kWh, fixed rate for 14 + years
Or 23.4/0.8x1.1^8 = 62.7 cents/kWh at an interest rate of 10% per year,
including battery and inverter inefficiencies...
>And how much intrest does you electricty supplier pay you on the money
>you pay for your energy.
None, but the rational question is not how much you electricty supplier
pay you, but rather how much you could make by investing the money you
would have spent on this expensive PV hobby in something else.
Nick
steve spence
much you could make by investing the money you
would have spent on computers in something else.
much you could make by investing the money you
would have spent on fishing/boating in something else.
much you could make by investing the money you
would have spent on the stock market in something else.
much you could make by investing the money you
would have spent on lottery tickets in something else.
much you could make by investing the money you
would have spent on model trains in something else.
A hobby is a hobby. We don't care how much we spend on it (our spouses do)
or if we can get a return. This stuff is expensive, but it has a warm fuzzy
feeling attached to it that other hobbies may not have.
--
Steve Spence
Subscribe to the Renewable Energy Newsletter:
http://www.webconx.com/subscribe.htm
Renewable Energy Pages - http://www.webconx.com
Palm Pilot Pages - http://www.webconx.com/palm
X10 Home Automation - http://www.webconx.com/x10
ssp...@webconx.com
(212) 894-3704 x3154 - voicemail/fax
We do not inherit the earth from our ancestors,
we borrow it from our children.
--
"Nick Pine" <ni...@ufo.ee.vill.edu> wrote in message
news:96rf8m$l...@ufo.ee.vill.edu...
Dlehmicke
>would have spent on this expensive PV hobby in something else.
>
>
A fair question to be asked about one's car purchase, house purchase, career
selection, children's education selection, children's braces selection,
vacation selection, selection of other hobbies, furniture selection, toy
selection, selection of liesure activities. Some of these choices have value
to the spender outside of economic considerations, just as PV electrons have
value over and above their electric bill value. The fact that these values
don't match yours doesn't make the decisions irrational.
James
last 15+ years it's important to try to size it to meet your next 15 years
worth of growth and future demand. All cells in a battery bank should be
the same age and be cycled the same number of times. This is a sometimes
overlooked detail by newbies building their new systems. The idea "I'll
start small and add more later" is great for inverters and panels, but for
batteries adding more later would require replacing the existing ones with
all new ones purchased from the same batch at the same time if proper
performance is desired.
-James
"David Kunz" <da...@clark.net> wrote in message
news:eXNj6.448164$w61.5...@dfw-read.news.verio.net...
Nick Pine
>much you could make by investing the money you
>would have spent on golf in something else.
>
>much you could make by investing the money you
>would have spent on computers in something else.
>
>much you could make by investing the money you
>would have spent on fishing/boating in something else.
>
>much you could make by investing the money you
>would have spent on the stock market in something else.
>
>much you could make by investing the money you
>would have spent on lottery tickets in something else.
>
>much you could make by investing the money you
>would have spent on model trains in something else.
These seem to be mostly personal choices without government subsidies...
Nick
steve spence
should someone else pay for my choices.
careful with the George Ghio comments, I might get offended ;-)
--
Steve Spence
Subscribe to the Renewable Energy Newsletter:
http://www.webconx.com/subscribe.htm
Renewable Energy Pages - http://www.webconx.com
Palm Pilot Pages - http://www.webconx.com/palm
X10 Home Automation - http://www.webconx.com/x10
ssp...@webconx.com
(212) 894-3704 x3154 - voicemail/fax
We do not inherit the earth from our ancestors,
we borrow it from our children.
--
"Nick Pine" <ni...@ufo.ee.vill.edu> wrote in message
news:96ro5t$l...@ufo.ee.vill.edu...
Paul Newhouse
"steve spence" <ssp...@webconx.com> writes:
> I've never taken a gov. subsidy for any hobby, including renewables. why
> should someone else pay for my choices.
It's called "social engineering" and the government does it all the time.
If you have a mortgage on 1 or 2 homes you can deduct your interest on
the mortgage(s) against you income. Essentially it's the same thing, you
get to reduce your tax bill based on your choices.
--
The lotto must be rigged, I should have won by now.
Modular furniture is cruel and unusual.
Sylvan Butler
> You don't buy a drill when you need a saw. Batteries are built to do
> different jobs. i.e. the alloy used in the plates is a good example.
> Also the sediment gap and reserve of electrolyte make a difference as
Exactly. And golf car batts, also known as floor scrubber batts, are
designed for daily deep discharge cycles in industrial use. The golf
and building maintenance industries don't replace these batteries every
day, or every year. Trojan rates their T105 at something like 750
cycles to 80% dod, which corresponds well to my friend's experience of
three to five years per set in his floor scrubber (taken to near 100%
every day of usage, ca. 250-300 days per year).
Don't let the low price fool you. A good golf car battery isn't
inexpensive because it is cheap. It is inexpensive because of economies
of scale. Shipping alone... These are shipped by the pallet load to
every corner of the U.S. and that is much cheaper than shipping a
half-dozen batts by special order.
The only reason to go with bigger batts is to lower the cell count or if
you simply need more amp-hours than feasible with 220ah units. You
won't find more cost effective storage where golf car batts meet the
size requirements.
sdb
--
More guns means less crime. ISBN:0-226-49363-6
***
Watch out for munged e-mail address.
User should be sylvandb1 and host is at bigfoot.com
Do NOT send me unsolicited commercial e-mail (UCE)!
Ron Rosenfeld
>More kargo kult knowledge? Sounds like a nicad vs lead-acid problem.
>
Surrette feels, for their deep discharge batteries, that they will only
have about 75% of their capacity until they have been cycled 10-40 times,
depending on the depth of discharge.
--ron
George L Ghio
<ni...@ufo.ee.vill.edu> wrote:
Ah yes the rational point of view. My $8,000 system vs $36,000 grid
connection.
I should have put my $8,000 in the bank and paid $36,000 to a foreign
owned power co.
Why I could pay off the $36,000 in what 40 years. Why didn't I think of
it.
Your hobby, My power supply. This is the difference.
George
George L Ghio
George L Ghio
George
In article <m9gk6.75558$%g3.12...@news02.optonline.net>, steve
George L Ghio
George L Ghio
floor scrubber.
George
In article <slrn98tbp9.6c.Zs...@p100.dbutler.org>, Sylvan
Paul Newhouse
Good for you. I didn't say you did. I was pointing out that the tax
code (among other government programs) makes various enticements available
if you choose to go along. Steve asked, "why should someone else pay for my
choices[?]". I don't know why (I know they always defend it as good economics,
this from an organization that hasn't been able to balance their checkbook in
more than 60 years ;), but the government does the "redistribution" of wealth
thing all the time via the tax code.
Paul
--
Sylvan Butler
> / background-thinking about a system that uses 2 or 3 smaller banks
> and ping-pongs between them to get better control over DOD and have
> better reserve capacity without using only a small portion of their
> capacity most of the time. This would also permit adding a set of new
> batteries to my system to increase my overall reserve without worrying
> about the fact that they'd be totally mismatched with the set I've
> been using. In normal use, I'd switch on a weekly basis. In bad
> charging conditions, I switch at about 50% DOD. And round-robin after
> that as they each go towards 20%.
I think that sounds like an excellent idea.
What ideas do you have for switches that would handle your 350amp draw?
Or were you thinking just switch cables (ick)?
> And, *for me*, I'd rather have the cash outlay for 1/2 of my batteries
> and only move 1/2 at a time twice as often than replace the whole
> thing at 2x the kerchunk! (hurts my back just thinking about it :)).
Yup!!!
George L Ghio
As for the mortgage bit I only put that in because Nick thinks that
"intrest" is the most important thing ever invented.
It is not. It does not even make the top 1000.
And what good is money in the bank while you sit in the dark.
Greed is a disease and Nick is termainal.
George
In article <Dolk6.12052$5M5.8...@news1.frmt1.sfba.home.com>, Paul
David Kunz
: Funny thing, I have the battery specs in front of me at the moment
: and battery life is given at 6-8 yearsat 50% DOD and 9-12 years at
: 25% DOD.
...
Dig deeper. How many amp-hours are produced over their life span in
both cases?
Nick Pine
>As for the mortgage bit I only put that in because Nick thinks that
>"intrest" is the most important thing ever invented.
>
>It is not. It does not even make the top 1000.
How unFerengi of you.
>Greed is a disease and Nick is termainal.
Each to his own obsession. When I told Steve Baer I was thinking of
spending $20K to avoid using $200 of oil per year to heat my house,
he said "That sounds like a very good idea." :-)
Nick
dw
selling in 5-8 years and completely moving to the country place.
While I would like to do more I must plan on the "resale risk" - or "taking it
with me".
No mortgage put why would I want to give someone 20K because I like the
comfort and feeling of Solar.
Now on the other hand the country place will be the "Last one" - already 18
months behind- I will put the "extras" there - sooner or later.
George L Ghio
Kunz <da...@clark.net> wrote:
> George L Ghio (gh...@netconnect.com.au) wrote:
>
> : Funny thing, I have the battery specs in front of me at the moment
> : and battery life is given at 6-8 yearsat 50% DOD and 9-12 years at
> : 25% DOD.
> ...
>
> Dig deeper. How many amp-hours are produced over their life span in
> both cases?
I does not matter. The point is that the batteries must do what I
require. i.e. 83 Ah a day for as long as possable.
I could run them to 50% DOD but then I would neer 50%+ more panels to
recharge them.
Balance. I defined my needs and built a balanced system to provide my
energy requirements.
George
George L Ghio
<ni...@acadia.ee.vill.edu> wrote:
Well there you are ya see, you are not "termainal" just very ill:+}
George
Sylvan Butler
> Funny thing, I have the battery specs in front of me at the moment and
> battery life is given at 6-8 yearsat 50% DOD and 9-12 years at 25% DOD.
And it takes 2x the battery bank to plan for 25% instead of 50% DOD.
Since those specs show you only get 50% more life, you just wasted your
money buying the extra batts necessary for 25% DOD.
Sylvan Butler
>> George L Ghio (gh...@netconnect.com.au) wrote:
>> Dig deeper. How many amp-hours are produced over their life span in
>> both cases?
>
> I does not matter. The point is that the batteries must do what I
It matters as to cost. If you want to spend as much as you need to
spend but not waste money, you need to know.
> I could run them to 50% DOD but then I would neer 50%+ more panels to
> recharge them.
Nonsense. The amount of panels you need is determined by the amount of
power you use and the amount of time you can collect charge. The amount
of batteries you need is determined by how deep you want to discharge
over how long.
Paul Newhouse
ni...@acadia.ee.vill.edu (Nick Pine) writes:
> George L Ghio <gh...@netconnect.com.au> wrote:
>
>>As for the mortgage bit I only put that in because Nick thinks that
>>"intrest" is the most important thing ever invented.
>>
>>It is not. It does not even make the top 1000.
Yeah, So? Bagels aren't either, but they are still a pretty clever
cream cheese delivery mechanism.
> How unFerengi of you.
>
>>Greed is a disease and Nick is termainal.
>
> Each to his own obsession. When I told Steve Baer I was thinking of
> spending $20K to avoid using $200 of oil per year to heat my house,
> he said "That sounds like a very good idea." :-)
I thought this was between you and George, so who cares what Steve thinks
(in this context).
I'm looking at $30-40K to get off $340/mo (now), could go to >$400/mo.
Six to ~11 year break even on investment.
So how is this fuel cell osmosis stuff doing? All I see in this ng is
reference to battery storage systems. Fuel cell is focusing on cars,
but it seems like a useful concept for stationary problems as well?
Paul
David Kunz
: On Mon, 19 Feb 2001 10:24:33 GMT, David Kunz <da...@clark.net>
:wrote:
: > / background-thinking about a system that uses 2 or 3 smaller
: > /banks
: > and ping-pongs between them to get better control over DOD and
: > have better reserve capacity without using only a small portion
: > of their capacity most of the time. This would also permit
: > adding a set of new batteries to my system to increase my overall
: > reserve without worrying about the fact that they'd be totally
: > mismatched with the set I've been using. In normal use, I'd
: > switch on a weekly basis. In bad charging conditions, I switch
: > at about 50% DOD. And round-robin after that as they each go
: > towards 20%.
: I think that sounds like an excellent idea.
: What ideas do you have for switches that would handle your 350amp
: draw? Or were you thinking just switch cables (ick)?
I don't have to switch that draw -- just carry it. If I switch first
thing in the morning, the systems only pulling a couple of amps from
the batteries.
My initial thoughts were to use breakers like the 250 amp mains in the
Trace control panel. But these are expensive. My next thought was to
to start checking the local ham-fests for big relays. These are
typically summer events, so it's still on the back burner :).
A few things that I wanted to consider are...
- Don't want to switch when there's charging or I risk overvoltage to
the inverters. Either need to switch-off the arrays during the switch
time or switch during dark (not a problem).
- Don't want both banks online at the same time unless both are fully
charged because of the major current flow that'll happen when the one
with the higher charge tries to charge the other (one of the reasons
for using breakers instead of switches :).
- I'd like the switching time to be small because I'll have no power
going to the house during the switch.
- How to get a good reading on battery state without having a
tri-metric-like meter on each bank of batteries. This one's easier
since one bank will always be at rest for long enough for the voltage
to settle. I can gradually build a table for each bank of tri-metric
meter's claimed state before switching (usually pretty good) vs.
no-load "sitting" voltage.
David Kunz
: David Kunz <da...@clark.net> writes:
: >...A factor here may be (also been discussed before) the fact that
: >if you don't go through a few full cycles to 20% of full charge
: >(80% DOD) when you initially install the batteries, the batteries
: >will not produce their full capacity when needed. This has also
: >been discussed here. I initially got this from the solar engineer
: >(again) and had it confirmed from other sources through battery
: >companies.
: More kargo kult knowledge? Sounds like a nicad vs lead-acid
:problem.
I seem to remember that it has to do with the initial plate
reformation after manufacturing -- but I don't claim to be a battery
expert. I don't have to know why to know how.
BTW, I see that you still attack personally when your store of
knowledge runs dry ...
David Kunz
: In article <YBsk6.454750$w61.5...@dfw-read.news.verio.net>, David
: Kunz <da...@clark.net> wrote:
: > George L Ghio (gh...@netconnect.com.au) wrote:
: > : Funny thing, I have the battery specs in front of me at the
: > : moment and battery life is given at 6-8 yearsat 50% DOD and
: > : 9-12 years at 25% DOD.
: > ...
: > Dig deeper. How many amp-hours are produced over their life span
: > in both cases?
: I does not matter. The point is that the batteries must do what I
: require. i.e. 83 Ah a day for as long as possable.
No argument there. My argument is based on 2 points:
1. To my knowledge and research, it does not hurt the battery to
discharge it to 50% -- regularly. In fact, they will probably produce
the most amp-hours over their life span and thus be efficient use of
our resources.
2. HOWEVER, good solar design is for 4-5 days of reserve capacity in
the batteries. This implies a "normal" daily discharge to about
15-20%.
SO, if you tout normal cycles to 15-20% as a good design point, I
heartily agree. If you claim that regular discharges below this is not
good battery care, I disagree.
George Estep
I expect to see fuel cells used in homepower systems much more
extensively in the near future than in automobiles. IMO, the homepower
product development is way ahead of the automotive technology.
http://www.hpower.com/homepage.html
Regards,
George Estep
"Paul Newhouse" <rockhe...@bigbox.wan.vpn> wrote in message
news:yhJk6.13964$5M5.1...@news1.frmt1.sfba.home.com...
George Estep
lead-acid batteries into homepower systems. The obvious conclusion is that
lead-acid batteries are not well suited for this application. What is
needed is a battery which is non-toxic, does not care what state-of-charge
it is operated in, yet will provide a 30 to 50 year life. Nickel-iron is
the battery which fits the bill for this application. Much easier
application and much lower life cycle costs are the result. Unfortunately
lead-acid is all the market is currently providing. That will change
soon...
Regards,
George Estep
"David Kunz" <da...@clark.net> wrote in message
news:0oMk6.455120$w61.5...@dfw-read.news.verio.net...
George L Ghio
Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
> On Wed, 21 Feb 2001 10:02:41 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
> >> George L Ghio (gh...@netconnect.com.au) wrote:
> >> Dig deeper. How many amp-hours are produced over their life span in
> >> both cases?
> >
> > I does not matter. The point is that the batteries must do what I
>
> It matters as to cost. If you want to spend as much as you need to
> spend but not waste money, you need to know.
>
> > I could run them to 50% DOD but then I would neer 50%+ more panels to
> > recharge them.
>
> Nonsense. The amount of panels you need is determined by the amount of
> power you use
1000 Watt hours (83.3Amp hours @ 12 Volts)
>and the amount of time you can collect charge.
4.5 PSH (mid winter)
> The amount
> of batteries you need is determined by how deep you want to discharge
> over how long.
5 days autonomy
Come on then size this system with a 50% DOD
George
George L Ghio
Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
> On Mon, 19 Feb 2001 22:23:43 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
> > Funny thing, I have the battery specs in front of me at the moment and
> > battery life is given at 6-8 yearsat 50% DOD and 9-12 years at 25% DOD.
>
> And it takes 2x the battery bank to plan for 25% instead of 50% DOD.
> Since those specs show you only get 50% more life, you just wasted your
> money buying the extra batts necessary for 25% DOD.
My DOD is 12% and I expect to get 20 years service. It can be done. It
has been done.
George
George L Ghio
And the top 20 if you were Jewish.
George
In article <yhJk6.13964$5M5.1...@news1.frmt1.sfba.home.com>, Paul
George L Ghio
Kunz <da...@clark.net> wrote:
> George L Ghio (gh...@netconnect.com.au) wrote:
>
> : In article <YBsk6.454750$w61.5...@dfw-read.news.verio.net>, David
> : Kunz <da...@clark.net> wrote:
>
> : > George L Ghio (gh...@netconnect.com.au) wrote:
>
> : > : Funny thing, I have the battery specs in front of me at the
> : > : moment and battery life is given at 6-8 yearsat 50% DOD and
> : > : 9-12 years at 25% DOD.
>
> : > ...
>
> : > Dig deeper. How many amp-hours are produced over their life span
> : > in both cases?
>
> : I does not matter. The point is that the batteries must do what I
> : require. i.e. 83 Ah a day for as long as possable.
>
> No argument there. My argument is based on 2 points:
>
> 1. To my knowledge and research, it does not hurt the battery to
> discharge it to 50% -- regularly. In fact, they will probably produce
> the most amp-hours over their life span and thus be efficient use of
> our resources.
>
> 2. HOWEVER, good solar design is for 4-5 days of reserve capacity in
> the batteries. This implies a "normal" daily discharge to about
> 15-20%.
>
> SO, if you tout normal cycles to 15-20% as a good design point, I
> heartily agree. If you claim that regular discharges below this is not
> good battery care, I disagree.
I am talking design and 5 days autonomy. A DOD of 50% will not give you
two days autonomy. If you have two days of no input then your batteries
will be 100% DOD. Your inverter would have quit well before that. You
could end up running the generator for 3-4 days. What a cost saveing
that is? If you do this often you will need a new set of batteries
every winters end. Another cost saving?
George
George L Ghio
replacement energy storage device that will 10 times the capacity in a
package I can hold in 1 hand. At half the price.
George
In article <t979e3b...@corp.supernews.com>, George Estep
Nick Pine
>...1000 Watt hours (83.3Amp hours @ 12 Volts)
Assuming this is the daily load...
>4.5 PSH (mid winter)
Irrelevant. (Although you might figure out how many panels
you need using this number, if you also knew their efficiency.)
>5 days autonomy
>Come on then size this system with a 50% DOD
Start with 10 kWh capacity. Discharge 10% per day...
Seems like a no-brainer. (Do you still measure resistors in amps? :-)
Nick
Paul Newhouse
> replacement energy storage device that will 10 times the capacity in a
> package I can hold in 1 hand. At half the price.
Ok. But right now today I don't have any batteries.
Paul
Paul Newhouse
"George Estep" <gke...@shentel.net> writes:
> Hi Paul,
>
> I expect to see fuel cells used in homepower systems much more
> extensively in the near future than in automobiles. IMO, the homepower
> product development is way ahead of the automotive technology.
Thanks for the pointers, I think I only had one of them.
Paul
George L Ghio
Since those specs show you only get 50% more life, you just wasted your
money buying the extra batts necessary for 25% DOD.
>> George L Ghio (gh...@netconnect.com.au) wrote:
>> Dig deeper. How many amp-hours are produced over their life span
in
>> both cases?
>
> I does not matter. The point is that the batteries must do what I
It matters as to cost. If you want to spend as much as you need to
spend but not waste money, you need to know.
> I could run them to 50% DOD but then I would neer 50%+ more panels to
> recharge them.
Nonsense. The amount of panels you need is determined by the amount of
power you use and the amount of time you can collect charge. The amount
of batteries you need is determined by how deep you want to discharge
over how long.
In article <970cp8$l...@ufo.ee.vill.edu>, Nick Pine
<ni...@ufo.ee.vill.edu> wrote:
>Seems like a no-brainer.
Suits you then.
Stated Capacity of system 1000 Watt hours (1kWh)
5 days autonomy
4.5 psh. The most relevant part of the whole thing, if it wont work in
winter you need more generator time, more expense.
50% DOD as Mr Butler assures us is the best option.
Now try again and we will see if your non brain can work it out.
Quoting my system sizing in an attempt to prove me wrong and Sylvan
right is a laugh.
George
David Kunz
: These are the types of hoops that users have been jumping through
: to fit lead-acid batteries into homepower systems. The obvious
: conclusion is that lead-acid batteries are not well suited for this
: application. What is needed is a battery which is non-toxic, does
: not care what state-of-charge it is operated in, yet will provide a
: 30 to 50 year life. Nickel-iron is the battery which fits the bill
: for this application. Much easier application and much lower life
: cycle costs are the result. Unfortunately lead-acid is all the
: market is currently providing. That will change soon...
I hope that it does!
But, isn't one of the problems with nickel-iron that it is less
efficient than lead-acid?
Sylvan Butler
[ strange quoting trimmed ]
> Quoting my system sizing in an attempt to prove me wrong and Sylvan
> right is a laugh.
What are you raving about???
Sylvan Butler
> So how is this fuel cell osmosis stuff doing? All I see in this ng is
> reference to battery storage systems. Fuel cell is focusing on cars,
> but it seems like a useful concept for stationary problems as well?
Fuel cells are more like a generator than a battery. They are
coming along....
Sylvan Butler
> In article <slrn996kle.6n.Zs...@p100.dbutler.org>, Sylvan
> Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
>
>> On Wed, 21 Feb 2001 10:02:41 +0800, George L Ghio <gh...@netconnect.com.au>
>> wrote:
>> >> George L Ghio (gh...@netconnect.com.au) wrote:
>> > I could run them to 50% DOD but then I would neer 50%+ more panels to
>> > recharge them.
>>
>> Nonsense. The amount of panels you need is determined by the amount of
>> power you use
Do you deny that?
Why do you try and change the subject like this:
> 1000 Watt hours (83.3Amp hours @ 12 Volts)
Over what time period? (Is that per day?)
>>and the amount of time you can collect charge.
>
> 4.5 PSH (mid winter)
In short, you need 1 days worth of panels to provide for today's usage,
plus (days autonomy)/(days to recover) worth of panels to recover from
your worst case "no sun" days.
So assuming the panels you chose will provide rated output at your peak
sun, and assuming you meant 1000wh/day, 1000wh/4.5h or 225 watts of
panels will provide your daily electrical usage. But did your "83.3amp
hours@12v" account for battery inefficiency? Probably not. So add 25%
to that and round up to 300watts of panels to provide 1 day's use. Now
to account for autonomy...
You left out a number. How many days of sun will you allow to recover
from your 5 days of no sun? If you want to be assured of full recovery
in one day, you will need 6 days worth of panel capacity, or about
1800watts. If you will allow full recovery to take 5 days, then you
only need 2 days worth, or 600watts of panels.
>> The amount
>> of batteries you need is determined by how deep you want to discharge
>> over how long.
>
> 5 days autonomy
> Come on then size this system with a 50% DOD
5 days, at 1000wh/day, you will use 5kwh of battery. To avoid dropping
below 50% then supply 10kwh of storage, or 8 x 220ah golf car batts,
less than US$500 approximately every 5 years.
Sylvan Butler
> I am talking design and 5 days autonomy. A DOD of 50% will not give you
Correct, for a _daily_ DOD of 50%.
> two days autonomy. If you have two days of no input then your batteries
> will be 100% DOD. Your inverter would have quit well before that. You
Yup.
> could end up running the generator for 3-4 days. What a cost saveing
Nope. You simply use the gen to charge the batts. My 10kwh batts will
charge from empty in about 6 hours and the gen has capacity to provide
double that full rate of charge. Oh, and running at half capacity it
uses about 1/2 gallon of gasoline (petrol) per hour.
Every second day with no sun would require running the generator for
LESS than 6 hours (as the batts would still be at 50%).
> that is? If you do this often you will need a new set of batteries
> every winters end.
Playing awfully fast and loose with the numbers, aren't you?
How do you figure that? Given ratings of 1000 cycles to 50%, you should
easily get five years per set (50% down every other day means less than
200 cycles per year).
George Estep
That is correct. There are three areas where NiFe efficiency is lower
than that of lead-acid. First, the chemistry, which is similar to NiCd or
NiMH, has a higher percentage difference between the charge and discharge
voltages than lead-acid. Second, the internal resistance of the cells is
higher, causing higher IR drops. Third, there is a much higher
self-discharge rate than lead-acid. Let's discuss these individually:
The difference in charge and discharge voltages, as it turns out, isn't
a significant factor in climates where it does not get very hot.
Specifically, the battery voltage will tend to be higher than in a lead-acid
system, causing the system to operate closer to the peak-power point of the
array, partially offsetting this effect. In higher temperature climates, it
makes sense to use fewer series cells in the battery to keep the charging
voltage in line with the peak power point of the array when at high
temperatures.
The internal resistance of all batteries, including lead-acid and
nickel-iron types, is about to be reduced significantly by an invention of a
metal foam plate to replace the many plates traditionally used in batteries.
This will reduce the effect of the resistance to a point where it won't be a
major factor. Additionally, the resistance of lead-acid batteries may be
lower when the battery is new, but it increases as the battery is cycled.
Eventually, it will become higher than the resistance for nickel-iron
batteries. My 48V, 600 Ah NiFe battery pack has a resistance, including all
of the wiring to the inverter, of about 84 mohm. (If anyone can provide
resistance measurements for a similarly-sized lead-acid battery bank, I
would be interested. I made the measurement by switching off a portion of
the array during charging conditions ensuring that the array was still
charging the battery and that the load current did not change, noting the
current which was interrupted and the voltage change which occurred at the
inverters.)
The higher self-discharge rate mainly occurs during the first day after
a charge, so in a PV system, this could result in about a 5% additional
loss. The self-discharge seems to be a percentage of the charge which was
recently applied. The reason I say that is I have built a small system
where the charge added to the battery is only about 10 % on an average day.
Yet, the battery gets fully charged, eventually. Perhaps someone can
confirm or deny whether my conclusion is correct.
All in all, I think these minor drawbacks are outweighed by the other
benefits, not the least of which is a much lower life-cycle cost.
Regards,
George Estep
"David Kunz" <da...@clark.net> wrote in message
news:CX5l6.455461$w61.5...@dfw-read.news.verio.net...
George Estep
I forgot to point out the major efficiency drawback of lead-acid
batteries...
The fact that lead acid batteries *must* attain a 100% state of charge
at least every couple of days results in operation of the system in an
inefficient manner. Here's why:
First, the lead-acid battery is less efficient in the state-of-charge
region between 80% and 100% state-of-charge. The result is that the system
is forced to be be operated where the battery is least efficient.
Second, whenever the battery is operated at 100% state-of-charge, it is
necessary to turn off the charging source. The result is that often a PV
array is sized larger than necessary to ensure the batteries are frequently
returned to 100% state-of-charge. The result is that system capacity is
added to account for battery limitations, but is essentially wasted. If a
generator is used to return the battery to 100% state-of-charge, then any
sunlight which is received will wasted, since it can't be placed in the
battery.
With my nickel-iron batteries, I virtually *never* operate my system at
100%, and therefore never turn off my array. The array is sized carefully
to the load and, like all systems, will sometimes come up short. When the
backup switches in, it does not recharge the batteries to 100% but to about
10%, waiting for the sun to return. That way, I don't have to use the
backup to provide energy that the sun could provide. Also, the battery is
operated away from the lower-efficiency region near 100% state-of-charge.
Regards,
George Estep
Nick Pine
>...you need 1 days worth of panels to provide for today's usage,
>plus (days autonomy)/(days to recover) worth of panels to recover
>from your worst case "no sun" days.
I disagree. If you use an average of 1 kWh/day and you get an average
equivalent 4.5 peak sun hours per day, you only need enough panels to
produce 1 kWh on an average day, accounting for inefficiencies...
Nothing more for "recovery."
>So assuming the panels you chose will provide rated output at your peak
>sun, and assuming you meant 1000wh/day, 1000wh/4.5h or 225 watts of
>panels will provide your daily electrical usage.
Right. That's the end of the story.
Nick
Nick Pine
> The fact that lead acid batteries *must* attain a 100% state of charge
>at least every couple of days results in operation of the system in an
>inefficient manner...
Every couple of days? Why not once a month?
Nick
George Estep
The information I have read indicates that the lead sulfate can harden
in as little as 24 hours in hot weather:
http://www.4unique.com/battery/battery_tutorial.htm
Read paragraph 8. Battery life and performance.
If you have information that indicates otherwise, I would be interested
in reading it.
Regards,
George Estep
"Nick Pine" <ni...@ufo.ee.vill.edu> wrote in message
news:973cvr$m...@ufo.ee.vill.edu...
D.A.Kopf
>
> Sylvan Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
>
> >...you need 1 days worth of panels to provide for today's usage,
> >plus (days autonomy)/(days to recover) worth of panels to recover
> >from your worst case "no sun" days.
>
> I disagree. If you use an average of 1 kWh/day and you get an average
> equivalent 4.5 peak sun hours per day, you only need enough panels to
> produce 1 kWh on an average day, accounting for inefficiencies...
> Nothing more for "recovery."
It would appear so mathematically, but in practice not necessarily true. Peaks
of power production will be clipped once the batteries are fully charged, if
there's no other place to store the energy. To illustrate with an extreme
example, suppose you use 7 kWh to do laundry once a week. Statistically with 1
kWh/day from PV panels the batteries will recharge over the next week. But
once you miss a laundry day you'll subsequently lose an entire week's worth of
charging. Use 14 kWh the next week to do twice the laundry, and after the
subsequent weekly recharge there'll still be a statistically persistent 7kWh
deficit in the battery bank. Even if you don't miss a laundry day, a week's
worth of 2x overproduction won't compensate for the next week's worth of clouds.
What would solve the problem would be a way to store all the energy from PV
panels, all the time. Grid tie inverters could do this, but the economics
don't seem favorable at the present. I like George Estep's point about
nickel-iron batts being more often available for energy storage (because not
minding partial charge conditions) but the 5% a day self discharge seems to
be a hefty penalty.
George Estep
Yes, five percent is a fairly high self-discharge. I should point out
that the self-disharge rate reduces with time, resulting in only 10% total
discharge over a 10 day period.
Regards,
George Estep
"D.A.Kopf" <d...@dakx.com> wrote in message
news:3A956B55...@dakx.com...
George L Ghio
All you have to do is prove that you can design a photovoltaic power
system that meets the following using a 50% DOD
1000 Watt hours per day
5 days autonomy
4.5 PSH per day
What you have offered so far is a system that needs the in put of a
generator for 1 day out of every two.
Everything you need to know is there
I do not care what batteries you use or the number or size of panels
You claim that a 50% DOD is the better way to go for battery life and
cost.
Now design the system.
George
In article <slrn9995us.6q.Zs...@p100.dbutler.org>, Sylvan
Nick Pine
>...Peaks of power production will be clipped once the batteries are fully
>charged, if there's no other place to store the energy.
Sounds like you are saying you need to have enough batteries, vs more
solar panels for "a 5-day recovery time."
>...once you miss a laundry day you'll subsequently lose an entire week's
>worth of charging. Use 14 kWh the next week to do twice the laundry, and
>after the subsequent weekly recharge there'll still be a statistically
>persistent 7kWh deficit in the battery bank...
One might say that's the result of using an average of 2 kWh/day.
Nick
David Kunz
: George Estep <gke...@shentel.net> wrote:
Sulphation.
BUT, a few questions that I have...
- How well does equalization control sulphation (as opposed to
simply getting the batteries to an "equal" state)? Does it
provide more margin for permitting the batteries to be somewhat
discharged for longer periods of time without permanent damage?
- Do the "solargizer" units work? Once again -- how well do these
units prevent permanent damage from sulphation that won't dissolve
on recharge? (They claim to actually recover batteries that are
sulphated).
Sylvan Butler
> Nick Pine wrote:
>>
>> Sylvan Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
>>
>> >...you need 1 days worth of panels to provide for today's usage,
>> >plus (days autonomy)/(days to recover) worth of panels to recover
>> >from your worst case "no sun" days.
>>
>> I disagree. If you use an average of 1 kWh/day and you get an average
>> equivalent 4.5 peak sun hours per day, you only need enough panels to
>> produce 1 kWh on an average day, accounting for inefficiencies...
>> Nothing more for "recovery."
>
> It would appear so mathematically, but in practice not necessarily true. Peaks
> of power production will be clipped once the batteries are fully charged, if
Exactly. If you do not provide extra panels for recovery, then recovery
may take the entire period used to calculate your "average peak sun
hours." e.g. in essence:
5/365 == effectively 0 extra panels.
But you cannot wait that long.
While your average daily production and average daily usage are exactly
the same over 1 year, in practical terms you really cannot take that
long to average out the charge in the batts.
This need to recover the batts more quickly than "average" is why you
add the extra (autonomy)/(recovery) worth of panels.
Now if you could have a big bank of capacitors instead of batts... :)
Sylvan Butler
> With my nickel-iron batteries, I virtually *never* operate my system at
> 100%, and therefore never turn off my array. The array is sized carefully
> to the load and, like all systems, will sometimes come up short. When the
> backup switches in, it does not recharge the batteries to 100% but to about
> 10%, waiting for the sun to return. That way, I don't have to use the
> backup to provide energy that the sun could provide. Also, the battery is
> operated away from the lower-efficiency region near 100% state-of-charge.
That sounds almost ideal... Almost as good as capacitors!
And then you mention lower life cycle costs in a previous post. Can you
point me to some more information and suppliers for NiFe batts?
Thanks,
George Estep
I agree ... almost ideally suited to the task.
Unfortunately, as far as I know, no one in North America manufacturers
NiFe batteries currently. To my knowledge, NiFe batteries are currently
manufactured in China, Russia, and Hungary. Here are a couple of links to
manufacturers.
http://www.changhong.com.au/
http://www.rigel.ru/assorteng/nickeliron/carriage/
A couple of vendors:
http://www.suntopway.com/inverter_battery.htm
http://tmec.com.cn/maindoc/others/battery/nickeliron/nife.htm
http://www.hyundaitrade.com/solar_24.html
http://www.armyradio.com/Default.htm?http&&&www.armyradio.com/publish/Batter
y's_For_Sale.htm
The performance and construction of the Chinese and Russia batteries leave a
lot to be desired. I was fortunate enough to buy modern NiFe batteries which
where built by Eagle Pitcher in the early 1990s for the Chrysler EPIC
minivan program. These have far superior performance and come in 6 V
configurations. Unfortunately, my source is all out and I don't know where
else I can buy them.
I have more technical information in PDF format on the Chinese batteries and
the Eagle-Pitcher batteries I use, if you are interested.
Finally, there is a company in Las Vegas which has invented a new structure
to help with all large batteries, including lead-acid and nickel-iron. They
also have invented a new chemistry for nickel-iron. The inventor is Alvin
Snaper, inventor of Tang, the IBM selectric ball, and some 600 other
patents. He is the only three-time winner of the inventor-of-the-year award:
no one else has ever won it twice. I have high hopes that they will bring
their advanced, low-cost battery technology to this market soon. You can
read their ugly, out-of-date web site at:
http://www.powertechnologyonline.com
The latest press release with measured performance of a lead-acid cell using
the new structure is available at the following link. The results are
somewhat confusing, but still quite impressive.
http://www.powertechnologyonline.com/R1T2whatsnew.html
Please let me know if I can be of further assistance.
Hope this helps,
George Estep
"Sylvan Butler" <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote in message
news:slrn99bmqb.7q.Zs...@p100.dbutler.org...
> On Thu, 22 Feb 2001 10:44:30 -0500, George Estep <gke...@shentel.net>
wrote:
steve spence
the hydrogen in a fuel cell, to produce a smaller amount of energy. just
like charging a battery, but more loss.
--
Steve Spence
Subscribe to the Renewable Energy Newsletter:
http://www.webconx.com/subscribe.htm
Renewable Energy Pages - http://www.webconx.com
Palm Pilot Pages - http://www.webconx.com/palm
X10 Home Automation - http://www.webconx.com/x10
ssp...@webconx.com
(212) 894-3704 x3154 - voicemail/fax
We do not inherit the earth from our ancestors,
we borrow it from our children.
--
"Sylvan Butler" <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote in message
news:slrn999645.6q.Zs...@p100.dbutler.org...
George L Ghio
design a solar power system that gives 5 days autonomy with a 50% DOD.
So why did you make the claim about 50% DOD being the better choice?
By the way the system you are trying to sound so knowledgable about
below (and failing miserably) requires 5 - 80 watt panels to have a
hope of working in winter.
An average of 4.5 PSH would put you inside the arctic circle.
It would appear the Pine and Butler are the comic duo of the new
millenium.
George
In article <slrn99bmj9.7q.Zs...@p100.dbutler.org>, Sylvan
Sylvan Butler
> - How well does equalization control sulphation (as opposed to
> simply getting the batteries to an "equal" state)? Does it
> provide more margin for permitting the batteries to be somewhat
> discharged for longer periods of time without permanent damage?
My understanding is "very little."
> - Do the "solargizer" units work? Once again -- how well do these
> units prevent permanent damage from sulphation that won't dissolve
> on recharge? (They claim to actually recover batteries that are
> sulphated).
I've been wondering about building the unit from homepower a few months
ago...
Sylvan Butler
> All you have to do is prove that you can design a photovoltaic power
> system that meets the following using a 50% DOD
>
> 1000 Watt hours per day
>
> 5 days autonomy
>
> 4.5 PSH per day
>
> What you have offered so far is a system that needs the in put of a
> generator for 1 day out of every two.
Balony.
And you still left out a number. How many recovery days?
Read:
> In article <slrn9995us.6q.Zs...@p100.dbutler.org>, Sylvan
> Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
>> In short, you need 1 days worth of panels to provide for today's usage,
>> plus (days autonomy)/(days to recover) worth of panels to recover from
>> your worst case "no sun" days.
>> So assuming the panels you chose will provide rated output at your peak
>> sun, and assuming you meant 1000wh/day, 1000wh/4.5h or 225 watts of
>> panels will provide your daily electrical usage. But did your "83.3amp
>> hours@12v" account for battery inefficiency? Probably not. So add 25%
>> to that and round up to 300watts of panels to provide 1 day's use. Now
>> to account for autonomy...
>> You left out a number. How many days of sun will you allow to recover
>> from your 5 days of no sun? If you want to be assured of full recovery
>> in one day, you will need 6 days worth of panel capacity, or about
>> 1800watts. If you will allow full recovery to take 5 days, then you
>> only need 2 days worth, or 600watts of panels.
>> 5 days, at 1000wh/day, you will use 5kwh of battery. To avoid dropping
>> below 50% then supply 10kwh of storage, or 8 x 220ah golf car batts,
>> less than US$500 approximately every 5 years.
sdb
--
Sylvan Butler
> Unfortunately, as far as I know, no one in North America manufacturers
> NiFe batteries currently. To my knowledge, NiFe batteries are currently
Figures.
> manufactured in China, Russia, and Hungary. Here are a couple of links to
> http://www.changhong.com.au/
>
> http://www.rigel.ru/assorteng/nickeliron/carriage/
>
> A couple of vendors:
>
> http://www.suntopway.com/inverter_battery.htm
>
> http://tmec.com.cn/maindoc/others/battery/nickeliron/nife.htm
>
> http://www.hyundaitrade.com/solar_24.html
>
> http://www.armyradio.com/Default.htm?http&&&www.armyradio.com/publish/Battery's_For_Sale.htm
>
> The performance and construction of the Chinese and Russia batteries leave a
> lot to be desired. I was fortunate enough to buy modern NiFe batteries which
> where built by Eagle Pitcher in the early 1990s for the Chrysler EPIC
Sounds like you were fortunate...
> I have more technical information in PDF format on the Chinese batteries and
That would be interesting... If it is on the websites above I'll find
it, otherwise... Is it of email-able size?
> Finally, there is a company in Las Vegas which has invented a new structure
> http://www.powertechnologyonline.com
>
> The latest press release with measured performance of a lead-acid cell using
> http://www.powertechnologyonline.com/R1T2whatsnew.html
Hmm, sounds intriguing.
> Hope this helps,
Definitely.
Thanks, now to do some reading! :)
Sylvan Butler
> D.A.Kopf <d...@dakx.com> wrote:
>>...once you miss a laundry day you'll subsequently lose an entire week's
>>worth of charging. Use 14 kWh the next week to do twice the laundry, and
>>after the subsequent weekly recharge there'll still be a statistically
>>persistent 7kWh deficit in the battery bank...
>
> One might say that's the result of using an average of 2 kWh/day.
Only for the week with two laundry days. Yearly average is still the
same.
George L Ghio
Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
> On Fri, 23 Feb 2001 18:55:22 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
> > All you have to do is prove that you can design a photovoltaic power
> > system that meets the following using a 50% DOD
> >
> > 1000 Watt hours per day
> >
> > 5 days autonomy
> >
> > 4.5 PSH per day
> >
> > What you have offered so far is a system that needs the in put of a
> > generator for 1 day out of every two.
>
> Balony.
In article <slrn999713.6q.Zs...@p100.dbutler.org>, Sylvan
Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
> Every second day with no sun would require running the generator for
> LESS than 6 hours (as the batts would still be at 50%).
Looks like you will be running your generator 1 out of 2 days to me. Or
4 out of 5 days if you had 5 days of no sun.
Can you hear the laughter. Its getting louder.
> > In article <slrn9995us.6q.Zs...@p100.dbutler.org>, Sylvan
> > Butler <ZsylvanDB...@Zhotmail.Zcom.invalid> wrote:
>
> >> In short, you need 1 days worth of panels to provide for today's usage,
> >> plus (days autonomy)/(days to recover) worth of panels to recover from
> >> your worst case "no sun" days.
>
> >> So assuming the panels you chose will provide rated output at your peak
> >> sun, and assuming you meant 1000wh/day, 1000wh/4.5h or 225 watts of
> >> panels will provide your daily electrical usage. But did your "83.3amp
> >> hours@12v" account for battery inefficiency? Probably not. So add 25%
> >> to that and round up to 300watts of panels to provide 1 day's use. Now
> >> to account for autonomy...
>
> >> You left out a number. How many days of sun will you allow to recover
> >> from your 5 days of no sun?
I did not leave out a number. I left it up to you to design the system
with a 50% DOD. Choose what you think is right.
1000 Watt hours per day
5 days autonomy
4.5 PSH per day
If you want to be assured of full recovery
> >> in one day, you will need 6 days worth of panel capacity, or about
> >> 1800watts. If you will allow full recovery to take 5 days, then you
> >> only need 2 days worth, or 600watts of panels.
>
> >> 5 days, at 1000wh/day, you will use 5kwh of battery. To avoid dropping
> >> below 50% then supply 10kwh of storage, or 8 x 220ah golf car batts,
> >> less than US$500 approximately every 5 years.
George
Ron Rosenfeld
wrote:
>
>1000 Watt hours (83.3Amp hours @ 12 Volts)
>4.5 PSH (mid winter)
>5 days autonomy
>
>Come on then size this system with a 50% DOD
>
George,
Tell me what I am missing or misinterpreting from your parameters:
Consumption = 1.00 kwh/day
PV array = five @ 100 watts (oversized a bit to minimize generator but
could be made a bit smaller).
Total PV production = 1.43 kwh/day
Batteries = 12V/1400AH (Could use eight 6V/350AH batteries)
Add battery charger, inverter, controller, small generator and wiring.
--ron
David Kunz
: On Fri, 23 Feb 2001 12:31:55 GMT, David Kunz <da...@clark.net>
:wrote:
: > - How well does equalization control sulphation (as opposed to
: > simply getting the batteries to an "equal" state)? Does it
: > provide more margin for permitting the batteries to be
: > somewhat discharged for longer periods of time without
: > permanent damage?
: My understanding is "very little."
Since I can tell that it's time to equalize because my batteries
charge too easily (voltage rises too fast for the DOD shown on my
trimetric meter), I thought that it might be helping. Must be another
explanation?
: > - Do the "solargizer" units work? Once again -- how well do
: > these units prevent permanent damage from sulphation that
: > won't dissolve on recharge? (They claim to actually recover
: > batteries that are sulphated).
: I've been wondering about building the unit from homepower a few
: months ago...
Someone's been unloading a bunch of them (solargizer units) on eBay.
I picked up a couple of 12-24v units for about $36.00 apiece (lowest
retail I could find was about $200 for the same units). I hooked one
up to my battery bank, but I think that I'm pushing it for the size of
the unit vs. the size of my battery bank. If I notice any difference
in performance, I'll share -- but it'll probably be subjective.
George L Ghio
<ronros...@spamcop.net> wrote:
> On Wed, 21 Feb 2001 23:12:30 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
>
>
> >
> >1000 Watt hours (83.3Amp hours @ 12 Volts)
> >4.5 PSH (mid winter)
> >5 days autonomy
> >
> >Come on then size this system with a 50% DOD
> >
>
> George,
>
> Tell me what I am missing or misinterpreting from your parameters:
>
> Consumption = 1.00 kwh/day
OK
>
> PV array = five @ 100 watts (oversized a bit to minimize generator but
> could be made a bit smaller).
5 X 100 x 4.5 = 2250
>
> Total PV production = 1.43 kwh/day
2.24 kW/day
>
> Batteries = 12V/1400AH (Could use eight 6V/350AH batteries)
6-2 volt 770Ah Will giv a 12% DOD/day
1400 Ah of batteries will give you a 6% DOD/Day
>
> Add battery charger, inverter, controller, small generator and wiring.
Ok
Well over sized for the job. You won't run out in a hurry.
George
Ron Rosenfeld
wrote:
>In article <rf7f9tkumb07c0ke9...@4ax.com>, Ron Rosenfeld
><ronros...@spamcop.net> wrote:
>
>> On Wed, 21 Feb 2001 23:12:30 +0800, George L Ghio <gh...@netconnect.com.au>
>> wrote:
>>
>>
>> >
>> >1000 Watt hours (83.3Amp hours @ 12 Volts)
>> >4.5 PSH (mid winter)
>> >5 days autonomy
>> >
>> >Come on then size this system with a 50% DOD
>> >
>>
>> George,
>>
>> Tell me what I am missing or misinterpreting from your parameters:
>>
>> Consumption = 1.00 kwh/day
>
>OK
>>
I see what you are getting at and also where our differences are.
First of all, when you specified 1kWh/day, I took the 1kWh/day to be
appliance load, and added in an additional amount for system
inefficiencies, PV module derating, etc. That's why my system seemed
oversized to you.
Also, when I've read about "DOD", I've taken that to mean the maximum DOD
to which the batteries will be subjected after the period of autonomy, and
not the daily DOD. Obviously, the daily DOD has to be less than the DOD
after five days of no sun. But I don't understand why the latter wouldn't
be the design parameter.
--ron
Nick Pine
>Also, when I've read about "DOD", I've taken that to mean the maximum DOD
>to which the batteries will be subjected after the period of autonomy, and
>not the daily DOD.
Our "solar power consultant" was vague about that.
>...I don't understand why the latter wouldn't be the design parameter.
It's hard to predict how often you'd reach the 5-day DOD. The frequency
of the daily DOD (daily :-) is more predictable, and can be related (or
not, if you are George Ghio) to the battery lifetime spec (and lifetime
energy storage cost) in # cycles vs DOD.
Nick
George L Ghio
<ronros...@spamcop.net> wrote:
> On Sun, 25 Feb 2001 12:41:59 +0800, George L Ghio <gh...@netconnect.com.au>
> wrote:
>
> >In article <rf7f9tkumb07c0ke9...@4ax.com>, Ron Rosenfeld
> ><ronros...@spamcop.net> wrote:
> >
> >> On Wed, 21 Feb 2001 23:12:30 +0800, George L Ghio <gh...@netconnect.com.au>
> >> wrote:
> >>
> >>
> >> >
> >> >1000 Watt hours (83.3Amp hours @ 12 Volts)
> >> >4.5 PSH (mid winter)
> >> >5 days autonomy
> >> >
> >> >Come on then size this system with a 50% DOD
> >> >
> >>
> >> George,
> >>
> >> Tell me what I am missing or misinterpreting from your parameters:
> >>
> >> Consumption = 1.00 kwh/day
> >
> >OK
> >>
>
>
> I see what you are getting at and also where our differences are.
>
> First of all, when you specified 1kWh/day, I took the 1kWh/day to be
> appliance load,
Thats right.
and added in an additional amount for system
> inefficiencies, PV module derating, etc. That's why my system seemed
> oversized to you.
All thease things are taken into account when sizing a system.
>
> Also, when I've read about "DOD", I've taken that to mean the maximum DOD
> to which the batteries will be subjected after the period of autonomy, and
> not the daily DOD. Obviously, the daily DOD has to be less than the DOD
> after five days of no sun. But I don't understand why the latter wouldn't
> be the design parameter.
It is. After five days of no sun your batteries would be 80% DOD
George