24V .vs. 48V revisited
Ecnerwal
For the better part of 3 years I've been creeping towards getting a
power system together - partly I take a long time researching stuff,
partly the longer I wait the more money I have (on the other hand, the
price of copper wire has roughly tripled).
I'm about to get it ordered.
I have been, based on early input from helpful folks here, leaning
strongly towards a 48V system. Smaller wire, smaller breakers, fewer
parallel strings in the battery for a given storage capacity and battery
size. Since I'm starting from scratch I don't need to match any existing
equipment, and I'm leaning to the "do it pretty much all with AC from
the inverter" approach as being cheaper than having various DC
appliances which are costly and rare (putting the cost into more
generation due to slightly lower efficiency - but I have other reasons
to want plenty of generation capacity - workshop loads, etc).
However, the pesky conundrum of a PV array that will, on the one hand,
charge a 48V bank effectively (in the hot season), and won't on the
other hand, fry the charge controller (in the cold season) is making me
seriously reconsider 24V as a system voltage.
--
Cats, coffee, chocolate...vices to live by
Solar Flare
availability with automotic circuits everywhere.
Most MPPT I have seen will accept from 50v to 120 vdc for a 48v bank.
"Ecnerwal" <Lawren...@SOuthernVERmont.NyET> wrote in message
news:LawrenceSMITH-225...@news.verizon.net...
SJC
at 200v, but I don't think I would like to have that high voltage DC around.
"Ecnerwal" <Lawren...@SOuthernVERmont.NyET> wrote in message news:LawrenceSMITH-225...@news.verizon.net...
Eeyore
Ecnerwal wrote:
> However, the pesky conundrum of a PV array that will, on the one hand,
> charge a 48V bank effectively (in the hot season), and won't on the
> other hand, fry the charge controller (in the cold season)
Where's the rpoblem ?
Graham
Ron Rosenfeld
<Lawren...@SOuthernVERmont.NyET> wrote:
>However, the pesky conundrum of a PV array that will, on the one hand,
>charge a 48V bank effectively (in the hot season), and won't on the
>other hand, fry the charge controller (in the cold season) is making me
>seriously reconsider 24V as a system voltage.
Use Outback MX60 controller(s) and, depending on how cold your area gets in
the winter, a nominal 60V or 72V array.
In eastern Maine, over the past few years, Voc has not been above 140V (max
rating of the MX60 is 150V) with a nominal 72V system.
--ron
Derek Broughton
My question too. If I was doing it over, I'd have a 48V system instead of a
24V.
--
derek
Windsun
http://store.solar-electric.com/outpowmxmp.html
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"Ecnerwal" <Lawren...@SOuthernVERmont.NyET> wrote in message
news:LawrenceSMITH-225...@news.verizon.net...
wmbjk
<solae...@hootmail.invalidated> wrote:
>24 v is nowhere. Go 48 for the capacity or 12 volt for the
>availability with automotic circuits everywhere.
12V? That's hilarious Gymmy Bob. Got a photo of any of those
"automotic" circuits?
Lawrence: Ron's advice hit the nail on the head.
Wayne
Eeyore
Windsun wrote:
> That is what the MX60 is for - you can use up to 140 volts DC on the input
>
> http://store.solar-electric.com/outpowmxmp.html
I still don't understand why he's worried that the charge controller would fry
in the *cold* season !
Graham
wmbjk
Because array voltage will be highest then. Read up here
http://www.outbackpower.com/forum/viewtopic.php?t=1698.
Wayne
Eeyore
wmbjk wrote:
You mean the temperature coefficient ? That's only open circuit anyway.
How cold does it get ?
Graham
Ecnerwal
Eeyore <rabbitsfriend...@hotmail.com> wrote:
Voltage, voltage, voltage. Panel voltage (both open circuit and peak
power) drops as temperature rises. It also rises as temperature drops.
So, on the one hand, I need enough voltage out of the panels when they
are hot (75-85C) in the summer to effectively charge (and if wet-cell,
equalize), while, at the same time, not frying the charge controller
when it's -30C (-22F) outside in the winter. The charge controller I
plan to use is an outback MX-60, which will fry (and take the warrantee
with it) if fed 150V or more VOC. I don't think there are any others
that do better, and nobody seems to make a "buck/boost" (change voltage
up or down) controller, only "buck" (change voltage down) types.
If I put together a "60 volt" array, it just about works. However "12V"
panels are going the way of the dinosaur, as far as I can tell. KC130s
may be it, and how long they will be around is anyone's guess. I
understand that Evergreen is stopping production of the "Cedar" series,
and the replacement "Spruce" panels are either too wimpy to charge (and
especially equalize) 48V in a stack of 3 when it's hot (75C 59.67V - 88C
54.36V), or too high voltage (156.46VOC @ -30C) to connect 4 of to an
MX-60 when it's cold. Buying 12 at a time and reconfiguring from 3
strings of 4 to 4 strings of 3 seasonally is possible, but seems like it
would get old fast (and probably violate the NEC, since you or a future
owner might forget to change the configuration and exceed the voltage
limits).
Further complicating my thought process is the fact that when Outback
has been updating their catalog/price list, they have downrated a bunch
of the stuff they had had uprated to 150VDC back to 125VDC, and that
means that the "60V" configuration (Max VOC of about 134V) would need
600V fuses instead of breakers, and then the GFI unit if your are roof
mounting it would not be rated to take it (that's also 125VDC per new
catalog, and goes upstream of the charge controller). Trace stuff is
also limited to 125 VDC. Outback tech on their forum claimed that the
150VDC rating applied to the PSPV and Breakers "as a unit", but I'm not
sure just how real that is, and it still does not resolve the GFI rating.
It becomes much easier to fit the open circuit when cold voltage below
125V and keep the peak power when hot voltage at/above the highest
charge/equalization voltage required when the battery is 24V. But
otherwise I greatly prefer 48....
Jens Kr. Kirkebø
<Lawren...@SOuthernVERmont.NyET> wrote:
>If I put together a "60 volt" array, it just about works. However "12V"
>panels are going the way of the dinosaur, as far as I can tell. KC130s
>may be it, and how long they will be around is anyone's guess. I
>understand that Evergreen is stopping production of the "Cedar" series,
>and the replacement "Spruce" panels are either too wimpy to charge (and
>especially equalize) 48V in a stack of 3 when it's hot (75C 59.67V - 88C
>54.36V), or too high voltage (156.46VOC @ -30C) to connect 4 of to an
>MX-60 when it's cold.
Drop the 12V/24V panels though and get some grid-tie panels. Like the
Mitsubishi 170W panels:
http://global.mitsubishielectric.com/bu/solar/products/pdf/pv_mf170eb3.pdf
Voc of 30.6V and Vmp of 24.6, should be excellent for series of 3.
$850 here: http://store.solar-electric.com/mi170wasoelp.html
GE 173W panels at 25.1Vmp:
http://www.gepower.com/prod_serv/products/solar/en/downloads/gepv_173_datasheet.pdf
Evergreen Spruce 170/180/190 will also work, like many others.
Ecnerwal
> >and the replacement "Spruce" panels are either too wimpy to charge (and
> >especially equalize) 48V in a stack of 3 when it's hot (75C 59.67V - 88C
> >54.36V), or too high voltage (156.46VOC @ -30C) to connect 4 of to an
> >MX-60 when it's cold.
Jens Kr. Kirkeb? <j...@scm.no> wrote:
> Drop the 12V/24V panels though and get some grid-tie panels. Like the
> Mitsubishi 170W panels:
...
> Voc of 30.6V and Vmp of 24.6, should be excellent for series of 3.
3 is 56.16V at 75C. Not So Good. The slightly lower VOC (.vs. Evergreen)
does mean that a 4 stack of those tops out at 145.69V @ -30C, so that
could work. Probably would not pass NEC with 150V components, since NEC
uses the 1.25 multiplier rather than the manufacturer's coefficients.
> GE 173W panels at 25.1Vmp:
...
3 of these yield 56.48 Vmp @ 75C
4 of these yield 157.4 VOC at -30C.
> Evergreen Spruce 170/180/190 will also work, like many others.
Having run the numbers for the Spruce 190 in the post you responded to,
perhaps your should read a bit closer. The Spruce 190 is the best of the
3 in a 3-stack configuration, but it's still a bit sketchy for charging
and particularly equalization on a hot, still day.
Ecnerwal
quantified, having lived through a couple of weeks of -20F two years
back, is whether anyone in the general (Northeast) or specific area (SW
Vermont) has temperature data for roof-mount panels in summer, where
it's much more of a guessing game. Air temperatures have been topping
100F regularly the past 2 years (unusual in the long term, but might
well be the new usual).
I guesstimate based on direct exposure that the roof gets to at least
50C/122F, and a supplier suggest that panels might get 30C above the
local area, leading to a 75-80C guesstimate. Anyone got actual data?
Jens Kr. Kirkebø
<Lawren...@SOuthernVERmont.NyET> wrote:
>> Drop the 12V/24V panels though and get some grid-tie panels. Like the
>> Mitsubishi 170W panels:
>...
>> Voc of 30.6V and Vmp of 24.6, should be excellent for series of 3.
>
>3 is 56.16V at 75C. Not So Good. The slightly lower VOC (.vs. Evergreen)
>does mean that a 4 stack of those tops out at 145.69V @ -30C, so that
>could work. Probably would not pass NEC with 150V components, since NEC
>uses the 1.25 multiplier rather than the manufacturer's coefficients.
But does it matter if the controller occasionally has to drive the
panels higher than Vmp ? (doesn't the MX60 do that maybe?) The power
trade-off is quite small a volt or so above, I've watched my MX60 do
it's scanning-thing too often ;)
Probably my background is showing here too, using my panels in the
norwegian mountains. Hot panels is usually not a problem...
>Having run the numbers for the Spruce 190 in the post you responded to,
>perhaps your should read a bit closer.
Sorry, got a little ahead of myself there.
But what about 4 of the Sharp ND167U3A ? Vmp at 23.5V and Voc of 29V,
4 makes Vmp at 94V and Voc at 116V. Even at 75C Vmp should be above
70V.
Augerus
"Ecnerwal" <Lawren...@SOuthernVERmont.NyET> wrote in message
news:LawrenceSMITH-225...@news.verizon.net...
As an Electrical Engineer who has experience in this area, I recommend going
with 48VDC for the following 3 simple reasons.
1. The NEC has a lot of requirements that come into play at 50V and above
(hence why 48V is so popular, code compliance costs money and failing to
follow code has legal ramifications).
2. There is plenty of equipment and experience in the 48VDC area.
3. The higher the voltage, the smaller the copper. Copper wire has more than
doubled in cost within the last year and will keep going up.
Last April I priced copper cable materials (from the same vendor) at over
$600.00 for the same project that only took $250.00 the year before.
Ron Rosenfeld
>That is what the MX60 is for - you can use up to 140 volts DC on the input
>
>http://store.solar-electric.com/outpowmxmp.html
>
>
Actually, 150V is the limitation at present. And it's supposed to be a
very hard limit -- I'm told the smoke comes out at 151.
--ron
Duane C. Johnson
Augerus <aug...@hotmail.com> wrote:
> As an Electrical Engineer who has experience in
> this area, I recommend going with 48VDC for the
> following 3 simple reasons.
> 1. The NEC has a lot of requirements that come into
> play at 50V and above (hence why 48V is so popular,
> code compliance costs money and failing to follow
> code has legal ramifications).
There is a basic problem here.
While we conveniently us the term "48V" to describe
these battery systems the fact of the mater is the
actual voltage is quite a bit higher than 50V.
Nominal rest voltage on a 12V lead acid battery is
more like 13.8V for a total of 55.2V. Hard nominal
charging can be 15V for a total of 60V.
And the voltage gets higher as the temperature goes
down.
Furthermore, the PV panels can have a maximum power
point voltage of around 18V for a total of 72V.
These same panels can have an open circuit voltage
of up to 22V for a total of 88V.
A nominal 36V system could have an circuit voltages
of 41.4V, 45V, 54V, or 66V.
A nominal 24V system could have an circuit voltages
of 27.6V, 30V, 36V, or 44V.
What does the NEC say about these real world voltages
and the 50V rules?
NEC also has things pertaining to "High Energy"
systems which most large storage batteries can have,
> 2. There is plenty of equipment and experience in
> the 48VDC area.
I agree and would also recommend 48V.
> 3. The higher the voltage, the smaller the copper.
> Copper wire has more than doubled in cost within
> the last year and will keep going up. Last April
> I priced copper cable materials (from the same
> vendor) at over $600.00 for the same project
> that only took $250.00 the year before.
Evpensive!!!
Duane
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Ecnerwal
"Augerus" <aug...@hotmail.com> wrote:
> As an Electrical Engineer who has experience in this area, I recommend going
> with 48VDC for the following 3 simple reasons.
>
> 1. The NEC has a lot of requirements that come into play at 50V and above
> (hence why 48V is so popular, code compliance costs money and failing to
> follow code has legal ramifications).
Must be one of those electrical engineers who doesn't pay much attention
to NEC. 12V systems are the only "sub 50 volt systems" per the NEC. 24V
and above systems can have system voltages above 50V under various
conditions, detailed in
http://www.homepower.com/files/codecorner60-72.pdf
(14th page) ...among other places.
Even if I was not planning to use a fancy charge controller, voltages
above 150 VDC would be quite feasible in my 48 V system, and battery
voltages are always going to be above 48V unless I want to beat my
batteries to death - 60 volts or more on equalizing wet cells is quite
possible, and 57.6 V would be a daily occurrence under ideal conditions.
Windsun
Here in Phoenix - which is MUCH hotter than you will ever get, the max
temperature we have ever seen a panel that had adequate air circulation
under it was around 155F. And that was with an air temperature of around
112F. Now, we obviously don't measure every panel we install, but we have
measured 5-6 typical installations, and the only time we have ever seen over
160F at the panel is when the owner mounted the panels directly to the roof
with no air space under them, so it was like a greenhouse.
And I also doubt the -20F. Not that it won't get that cold, but will it ever
get that cold on the panels with the sun shining on them?
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"Ecnerwal" <Lawren...@SOuthernVERmont.NyET> wrote in message
news:LawrenceSMITH-8AC...@news.verizon.net...
Ecnerwal
"Windsun" <wind...@earthlink.net> wrote:
> I find that 80C a bit hard to believe.
>
> Here in Phoenix - which is MUCH hotter than you will ever get, the max
> temperature we have ever seen a panel that had adequate air circulation
> under it was around 155F. And that was with an air temperature of around
> 112F. Now, we obviously don't measure every panel we install, but we have
> measured 5-6 typical installations, and the only time we have ever seen over
> 160F at the panel is when the owner mounted the panels directly to the roof
> with no air space under them, so it was like a greenhouse.
Good. 68C in Phoenix, should indeed mean that can probably guess 60C as
a peak in Vermont and be safe - and that makes the numbers look much
better. I realized in the course of this discussion that I was making a
questionable assumption based on lousy data or no data about the high
end temperature, and I'm delighted to get some better input on what it
might really be (or at least, not be). I am planning to mount in a
fashion that should allow for air circulation, so perhaps I can just set
up a lower-voltage stack and get on with it.
Thanks!
> And I also doubt the -20F. Not that it won't get that cold, but will it ever
> get that cold on the panels with the sun shining on them?
Yes, that can happen. It does not happen every year, but it does happen
that we have stretches (typically in February) where it sits at -20F,
even with the sun shining. It might get up to -10F in the middle of the
day, but there will be stretches of morning and afternoon where it's
-20F with the sun shining. But that will be fine with a 3-stack of
Spruce panels (117.3VOC per the panel specs, 123VOC per NEC method).
DJ
Ecnerwal wrote:
> My head hurts.
>
> For the better part of 3 years I've been creeping towards getting a
> power system together - partly I take a long time researching stuff,
> partly the longer I wait the more money I have (on the other hand, the
> price of copper wire has roughly tripled).
>
> I'm about to get it ordered.
>
> I have been, based on early input from helpful folks here, leaning
> strongly towards a 48V system. Smaller wire
Debatable. With PV, the advent of the MX-60 from OutBack neutered this
concern. Bumping your array to 72v nominal makes a 48v array LESS
effective.
SWWP and probably others make high-voltage versions of their wind
turbines (like the HV-200), eliminating wiring concerns there, too.
Microhydro, though, yes, would be a serious concern if in the system.
Distances are almost always great, and line loss becomes a serious
issue.
>, smaller breakers
Looking at my price lists, a 175a main disconnect breaker is the same
price as a 250, and for smaller, a 10a breaker is the same price as a
20. Not a concern.
> fewer
> parallel strings in the battery for a given storage capacity and battery
> size.
To play devil's advocate, though, what we're talking about is the risk
of battery cell failure. And if you loose a single battery in a
single-series string, your entire bank is down until you get a
replacement. If you lose a single battery in a series/parallel system,
a string is down. The choice is very dependant on client situation and
financial resources.
I have heard it directly from Surrette/Rolls, for instance, that they
see no problems with using a 2-3 string series-parallel system.
> Since I'm starting from scratch I don't need to match any existing
> equipment, and I'm leaning to the "do it pretty much all with AC from
> the inverter" approach as being cheaper than having various DC
> appliances which are costly and rare (putting the cost into more
> generation due to slightly lower efficiency - but I have other reasons
> to want plenty of generation capacity - workshop loads, etc).
Agreed. Alot of my clients will use inverter-controlled generators for
doing workshop type stuff.
> However, the pesky conundrum of a PV array that will, on the one hand,
> charge a 48V bank effectively (in the hot season), and won't on the
> other hand, fry the charge controller (in the cold season) is making me
> seriously reconsider 24V as a system voltage.
MX-60, problem solved. After about 400 watts of PV, the MPPT function
alone paid for the MX-60 itself.
I'm not a big fan of 48v, mostly because in my installations, 48v stuff
is hard to come by and/or more expensive in alot of items you'd want
to use, like pumps and air handling fans. And I'm not sold on just
doing it AC and taking the hit. Folks up here (Canada) generally use
the smallest system possible, as we don't have any goverment programs
to help pay for the gear.
A matter of choice, really, very dependant on the individual client's
needs and wants. So, my opinion, 24 or 48 is not clear cut.
Just don't go 12 ;-).
DJ
Jens Kr. Kirkebø
>MX-60, problem solved. After about 400 watts of PV, the MPPT function
>alone paid for the MX-60 itself.
Yep, I have 450 watts and the MX60 wil definately pay for itself.
>A matter of choice, really, very dependant on the individual client's
>needs and wants. So, my opinion, 24 or 48 is not clear cut.
>
>Just don't go 12 ;-).
In my case, it was 12 or 48. 24 was not really an option. I could go
48V but then I'd have to run everything on 230V. That would have used
quite a bit more energy, since the VFX-inverter uses 20W alone + ~90%
efficiency conversion.
So I went with 12V and a VFX2612E. The only really thick wires was the
4/0 from the batteries to the inverter. All lighting are 12V (little
24V available, more or less no 48V). All cell-phone chargers are 12V,
fridge is 12V, TV is 12V, satellite tuner is 12V, DVD-player is 12V,
radio is 12V etc. You get the picture. Most of this stuff (except
fridge and cell-phone chargers) is hard to come by in 24V versions so
I'd have to run the inverter all the time and then I could just as
well do 48V.
George Ghio
Size everything correctly and relax.
--
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Ecnerwal
"DJ" <dj_mac...@hotmail.com> wrote:
Thanks for the usual high-quality input, DJ.
> Looking at my price lists, a 175a main disconnect breaker is the same
> price as a 250, and for smaller, a 10a breaker is the same price as a
> 20.
It's only $50, but I had noticed that if I went with a FX3048T it only
required a 100 amp breaker, and the 100 amp breaker was about 1/2 the
price of the 175 the VFX 3648 needs (which is, indeed, the same price as
a 250).
Inverter $/watt is quite similar between the FX and VFX for the 48 V
versions, and 2 FX are cheaper than 2 VFX to start with, while 3 FX
would supply more power than 2 VFX. On the 3rd hand, the fact that the
turbo fan eats the auxiliary output is one reason (aside from absolute
maximum power, which I don't see as being a large concern, not really
anticipating ever going past 4 inverters, if I ever get beyond 2) to
reconsider the VFX.
Ron Rosenfeld
>And I also doubt the -20F. Not that it won't get that cold, but will it ever
>get that cold on the panels with the sun shining on them?
It'll be that cold first thing in the morning when there is enough light to
"wake up" the panels, but insufficient time for them to warm up.
Granted the panels won't stay at ambient temperature and will warm as the
day goes on, but they sure can be that cold at "first light". And it is
apparently voltage and not current that will fry the MX60.
--ron
Eeyore
Ecnerwal wrote:
> In article <45704195...@hotmail.com>,
> Eeyore <rabbitsfriend...@hotmail.com> wrote:
>
> > Windsun wrote:
> >
> > > That is what the MX60 is for - you can use up to 140 volts DC on the input
> > >
> > > http://store.solar-electric.com/outpowmxmp.html
> >
> > I still don't understand why he's worried that the charge controller would fry
> > in the *cold* season !
>
> Voltage, voltage, voltage. Panel voltage (both open circuit and peak
> power) drops as temperature rises. It also rises as temperature drops.
OK, so you're worried about overvoltage damage in the cold when the charge
controller's presenting no load to the panel.
In part that appears to me to be a design oversight wrt the charge controller but
there's a simple fix.
It's almost trivailly simple to organise an overvoltage protection unit that simply
connects another load when the panel voltage approaches the 'danger voltage'.
I could easily design one for you for example.
Graham
Eeyore
Ron Rosenfeld wrote:
Bad design I'd say !
Graham
Eeyore
"Duane C. Johnson" wrote:
> Hi Augerus;
>
> Augerus <aug...@hotmail.com> wrote:
>
> > As an Electrical Engineer who has experience in
> > this area, I recommend going with 48VDC for the
> > following 3 simple reasons.
>
> > 1. The NEC has a lot of requirements that come into
> > play at 50V and above (hence why 48V is so popular,
> > code compliance costs money and failing to follow
> > code has legal ramifications).
>
> There is a basic problem here.
> While we conveniently us the term "48V" to describe
> these battery systems the fact of the mater is the
> actual voltage is quite a bit higher than 50V.
I suspect this is why auto electrics are heading towards '42V' systems AIUI. I
imagine that this means '36V' batteries.
Bear in mind that a '12V' battery is actually 12.6V and the typical charge
voltage is between 13.8 and 14.4V.
The 42V system is always below that 50V threshold.
Graham
Duane C. Johnson
Eeyore <rabbitsfriend...@hotmail.com> wrote:
> "Duane C. Johnson" wrote:
> > Augerus <aug...@hotmail.com> wrote:
> > > As an Electrical Engineer who has experience in
> > > this area, I recommend going with 48VDC for the
> > > following 3 simple reasons.
> > > 1. The NEC has a lot of requirements that come
> > > into play at 50V and above (hence why 48V is so
> > > popular, code compliance costs money and failing
> > > to follow code has legal ramifications).
> > There is a basic problem here.
> > While we conveniently us the term "48V" to describe
> > these battery systems the fact of the mater is the
> > actual voltage is quite a bit higher than 50V.
> I suspect this is why auto electrics are heading
> towards '42V' systems AIUI. I imagine that this
> means '36V' batteries.
I remember that the proposed automotive lead acid
battery has 20 cells. I suppose this is
2.1V / cell * 20 cells = 42V
> Bear in mind that a '12V' battery is actually 12.6V
> and the typical charge voltage is between 13.8 and
> 14.4V.
Yup, 20 cells with the equivalent if a 12V charging
at 14.4V rate would be 2.4V/cell:
2.4V / cell * 20 cells = 48V
Although higher fault charging conditions could
exceed 50V I suppose.
> The 42V system is always below that 50V threshold.
I have to say that the National Electrical Code
technically doesn't apply to the transportation
industry, well at least not in the vehicles anyway.
> Graham
Eeyore
"Duane C. Johnson" wrote:
International IEC regs are more important than US ones tbh and 42V is officially
classifed by them as a 'low voltage' which makes things a bit simpler.
Graham
nicks...@ece.villanova.edu
>OK, so you're worried about overvoltage damage in the cold when the charge
>controller's presenting no load to the panel.
>
>In part that appears to me to be a design oversight wrt the charge controller
>but there's a simple fix.
If it's so simple...
>It's almost trivailly simple to organise an overvoltage protection unit that
>simply connects another load when the panel voltage approaches the 'danger
>voltage'.
>
>I could easily design one for you for example.
It might have to be UL-approved and "an integral part of the panel" to help.
Nick
Ron Rosenfeld
Bad design?
Why do you say that?
--ron
Eeyore
nicks...@ece.villanova.edu wrote:
> Eeyore <rabbitsfriend...@hotmail.com> wrote:
>
> >OK, so you're worried about overvoltage damage in the cold when the charge
> >controller's presenting no load to the panel.
> >
> >In part that appears to me to be a design oversight wrt the charge controller
> >but there's a simple fix.
>
> If it's so simple...
It is. As to why others don't I can only conjecture.
> >It's almost trivailly simple to organise an overvoltage protection unit that
> >simply connects another load when the panel voltage approaches the 'danger
> >voltage'.
> >
> >I could easily design one for you for example.
>
> It might have to be UL-approved and "an integral part of the panel" to help.
UL approval is only relevant to the USA so you may only get US manufacvturers
bothering with that.
Why would it need to be covered for something that's not mains powered anyway ?
Graham
Eeyore
Ron Rosenfeld wrote:
Higher voltage rating semiconductors are easy to come by.
Maybe they had some reason to make it only 125 or 150V ?
Graham
Ron Rosenfeld
<rabbitsfriend...@hotmail.com> wrote:
>
>> >
>> >Bad design I'd say !
>> >
>>
>> Bad design?
>>
>> Why do you say that?
>
>Higher voltage rating semiconductors are easy to come by.
>
>Maybe they had some reason to make it only 125 or 150V ?
>
Not being involved in the design phase of this unit, I wouldn't know.
And if they did have a good reason, would that make it not a bad design, in
your opinion?
I guess I'm wondering how you can critique this sort of design based on a
published voltage limitation.
Do you think they can build one with a higher voltage limit, that would
have the same reliability, peformance and price?
What semiconductors would you use in place of the one's that are in there
now?
--ron
Eeyore
Ron Rosenfeld wrote:
> On Sun, 03 Dec 2006 13:49:16 +0000, Eeyore
> <rabbitsfriend...@hotmail.com> wrote:
>
> >> >Bad design I'd say !
> >>
> >> Bad design?
> >>
> >> Why do you say that?
> >
> >Higher voltage rating semiconductors are easy to come by.
> >
> >Maybe they had some reason to make it only 125 or 150V ?
>
> Not being involved in the design phase of this unit, I wouldn't know.
>
> And if they did have a good reason, would that make it not a bad design, in
> your opinion?
>
> I guess I'm wondering how you can critique this sort of design based on a
> published voltage limitation.
Because I'm an electronics consultant and my job amongst other things is to fix
other ppl's screw ups !
> Do you think they can build one with a higher voltage limit, that would
> have the same reliability, peformance and price?
Easily. It's a quite trivial task.
> What semiconductors would you use in place of the one's that are in there
> now?
Give me a schematic and I'll give you the numbers !
I *am* quite genuinely interested in developing products for the 'alternative
energy market' and I can bring a wealth of experience to that.
Graham
Windsun
diode across the panels.
--
-------------------------------------------------------------------------
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"Eeyore" <rabbitsfriend...@hotmail.com> wrote in message
news:45722E07...@hotmail.com...
Ron Rosenfeld
Well, I'd be interested in an MX60 with a bit higher voltage limit. And,
I'm sure others would be also.
I don't have a schematic, but http://www.outbackpower.com/ is the URL for
their website, and I'm sure they would be happy to discuss things further
with you.
Keep us posted!
--ron
Derek Broughton
>
>
> Windsun wrote:
>
>> That is what the MX60 is for - you can use up to 140 volts DC on the
>> input
>>
>> http://store.solar-electric.com/outpowmxmp.html
>
> I still don't understand why he's worried that the charge controller would
> fry in the *cold* season !
Outputs are higher?
--
derek
Derek Broughton
> UL approval is only relevant to the USA so you may only get US
> manufacvturers bothering with that.
>
> Why would it need to be covered for something that's not mains powered
> anyway ?
One word - insurance.
I guarantee you that if you have a fire in your electrical system and
there's any non-UL component in there, your insurance company will refuse
to pay. You may eventually prove that the part wasn't contributary, and
win an award, but they'll fight you every step of the way.
--
derek
clareatsnyder.on.ca
UL means Underwriter's Labs. Yup - insurance!!!
Solar Flare
windmill producing 250vac open circuit I doubt they can make a higher
voltage input tolerance or they would have done it.
I am not impressed with either their lack of knowledge or their
advertising lies.
"Ron Rosenfeld" <ronros...@nospam.org> wrote in message
news:3g88n2lmccte558vd...@4ax.com...
Eeyore
Windsun wrote:
> Well, the easy way is to just put something like a 20-30 amp 135 volt Zener
> diode across the panels.
Monstrously expensive. That's 2.7kW of dissipation for starters.
Graham
Ron Rosenfeld
<solae...@hootmail.invalidated> wrote:
>They are calling the MX-60 a wind turbine MPPT also. With my 1kW/48vdc
>windmill producing 250vac open circuit I doubt they can make a higher
>voltage input tolerance or they would have done it.
>
>I am not impressed with either their lack of knowledge or their
>advertising lies.
>
Let's see. From their spec sheet:
Hydro / Wind Turbine Applications
Consult factory for approved turbines
So, when you consulted the factory, did they say your turbine was approved?
--ron
Solar Flare
approve most of the turbines out there with brand names on them?
What brands are approved for such a restricted ability, unlikely to
handle windmills, type MPPT? I doubt many 48vdc units will produce
less voltage than 120vdc open circuited with a good wind and would be
interested in the brands that will work with it. My two units would
eat it for breakfast.
"Ron Rosenfeld" <ronros...@nospam.org> wrote in message
news:9onan2d3embovgmao...@4ax.com...
wmbjk
<solae...@hootmail.invalidated> wrote:
>"Ron Rosenfeld" <ronros...@nospam.org> wrote in message
>news:9onan2d3embovgmao...@4ax.com...
>> On Mon, 4 Dec 2006 20:46:11 -0500, "Solar Flare"
>> <solae...@hootmail.invalidated> wrote:
>>
>>>They are calling the MX-60 a wind turbine MPPT also. With my
>>>1kW/48vdc
>>>windmill producing 250vac open circuit I doubt they can make a
>>>higher
>>>voltage input tolerance or they would have done it.
>>>
>>>I am not impressed with either their lack of knowledge or their
>>>advertising lies.
>>>
>>
>> Let's see. From their spec sheet:
>>
>> Hydro / Wind Turbine Applications
>> Consult factory for approved turbines
>>
>>
>> So, when you consulted the factory, did they say your turbine was
>> approved?
>> --ron
>
>My turbine does not have a brand name on it. How would they be able to
>approve most of the turbines out there with brand names on them?
>
>What brands are approved for such a restricted ability, unlikely to
>handle windmills, type MPPT? I doubt many 48vdc units will produce
>less voltage than 120vdc open circuited with a good wind and would be
>interested in the brands that will work with it. My two units would
>eat it for breakfast.
>
You need the MX60i. It's a special version designed for compatibility
with invisible hardware. It's good for 1000V on all troll no-name
turbines. Order this month and receive a free 40oz bottle of
Thunderbird, which should get you through a few more posts.
Wayne
Ron Rosenfeld
<solae...@hootmail.invalidated> wrote:
>My turbine does not have a brand name on it. How would they be able to
>approve most of the turbines out there with brand names on them?
>
>What brands are approved for such a restricted ability, unlikely to
>handle windmills, type MPPT? I doubt many 48vdc units will produce
>less voltage than 120vdc open circuited with a good wind and would be
>interested in the brands that will work with it. My two units would
>eat it for breakfast.
Why ask here? Why not direct your question to the factory?
I guess your wind turbine doesn't meet the specifications clearly outlined
in their advertising. Was there something in their advertising that led
you to believe otherwise?
--ron
Solar Flare
MX-60 because their input ratings are garbage when it comes to wind
turbine generators. I don't need to ask them, I can read their specs
and they ain't compatible.
Maybe you can present a list of wind turbines in the 500W-1500W area
and their open circuit voltages with their rated windspeed applied. I
will await your reply. Maybe you can direct us to a website that
mentions this factor for any of them.
"Ron Rosenfeld" <ronros...@nospam.org> wrote in message
news:921en21ekpltgvci7...@4ax.com...
Solar Flare
read on their wond turbine unit so far says it is the same unit
renamed.
WTF is "Thunderbird"?
"wmbjk" <wmbjk...@citlink.net> wrote in message
news:ermdn256utbaettum...@4ax.com...
Ron Rosenfeld
<solae...@hootmail.invalidated> wrote:
>Now why would I direct my questions to the factory?
Why? To get answers to your questions.
>I don't want an
>MX-60 because their input ratings are garbage when it comes to wind
>turbine generators. I don't need to ask them, I can read their specs
>and they ain't compatible.
With regard to your wind turbine, although it's unlikely to be approved
since you said it was unbranded, you seemed to be concerned about the max
voltage allowed. And you wrote "With my 1kW/48vdc windmill producing
250vac open circuit ..."
Your 48 VDC is well below the maximum DC voltage rating.
What is the MX60 maximum AC voltage rating? I could not locate it on the
spec sheet.
>
>Maybe you can present a list of wind turbines in the 500W-1500W area
>and their open circuit voltages with their rated windspeed applied. I
>will await your reply. Maybe you can direct us to a website that
>mentions this factor for any of them.
If you were interested, I'm sure you could do that yourself, if you could
find the data on the mfg web site. I did not research turbines in that
power range when I set up my system, so I don't know if the information is
there.
I don't even know what the open circuit maximum (AC) voltage of my Bergey
XL-R is, or I'd post that for you. Maybe one of these days I'll measure
it.
Surely if you need a good controller for your wind turbine, you could
puchase or design something specifically tailored to it. Why even bring up
wind and the MX60 in this thread? Do you have a beef with the company?
It's clear to me that their marketing thrust is for its use as a solar
controller.
--ron
Solar Flare
only retorted that I didn't trust a company listing a 120 vdc input as
a windmill MPPT.
What does my 48vdc system have to do with anything? The input to a
MPPT can be completely no load when the batteries are charged or the
grid is down.
The MX-60 takes dc input. This was stated many times by different
people.
Most of the so called "windmill experts" have no idea what their
machines will put out open circuited. When I tell them my measurements
they cannot believe it and tell me how their units would never do that
because the specs are never published and most have never held a
voltmeter or put on a pair of insulated gloves.
Questions to the factory? I never had any questions to the factory.
You were the one suggesting I ask them something I don't need to know.
I already own two wind turbines and there is no pint in asking what
brand i should have bought. If they knew they would list them, I would
think.
"Ron Rosenfeld" <ronros...@nospam.org> wrote in message
news:hu2fn2ltumkrvhqrb...@4ax.com...
Ron Rosenfeld
<solae...@hootmail.invalidated> wrote:
>You must be confused. I did not bring up the MX-60 in this thread. I
>only retorted that I didn't trust a company listing a 120 vdc input as
>a windmill MPPT.
Outback doesn't make that claim on their spec sheets. Obviously you have
your facts wrong, but your mind is made up. But don't let that stop you
(I'm sure it won't).
>
>What does my 48vdc system have to do with anything? The input to a
>MPPT can be completely no load when the batteries are charged or the
>grid is down.
Oh, I thought you were concerned about the maximum voltage ratings on the
MX60. 48vdc was the highest DC voltage you posted about your wind system.
>
>The MX-60 takes dc input. This was stated many times by different
>people.
>
>Most of the so called "windmill experts" have no idea what their
>machines will put out open circuited. When I tell them my measurements
>they cannot believe it and tell me how their units would never do that
>because the specs are never published and most have never held a
>voltmeter or put on a pair of insulated gloves.
>
>Questions to the factory? I never had any questions to the factory.
>You were the one suggesting I ask them something I don't need to know.
It seems there is very little you need to know.
>I already own two wind turbines and there is no pint in asking what
>brand i should have bought. If they knew they would list them, I would
>think.
I can see it know. A section on their website listing "What Solar Flare
should have bought"!!
Or maybe, in keeping with your current email, "What solaerfart should have
bought"
Thanks for my morning amusement.
--ron
wmbjk
<solae...@hootmail.invalidated> wrote:
>"wmbjk" <wmbjk...@citlink.net> wrote in message
>news:ermdn256utbaettum...@4ax.com...
>> You need the MX60i. It's a special version designed for
>> compatibility
>> with invisible hardware. It's good for 1000V on all troll no-name
>> turbines. Order this month and receive a free 40oz bottle of
>> Thunderbird, which should get you through a few more posts.
>>
>> Wayne
>
>Thanx Wayne.
You're welcome. It's always my pleasure to elucidate uncommon levels
of expertise.
> I will attempt to research that one.
Now you're talkin'. BTW, only the tier 5 engineers at the factory know
about the MX60i model. So you'll need to work your way up the ladder
until you reach someone who's comfortable with your level of
knowledge. Just mention insulated gloves to the receptionist and
she'll bump you up right away.
> The stuff I have
>read on their wond turbine unit so far says it is the same unit
>renamed.
It's actually quite different. The wond turbine variation uses the
latest flux capacitor technology, and can automatically sense single
phase, three phase, and DC inputs up to 1000V. It's also capable of
overunity power conversion if you're willing to accept a 21% decrease
in efficiency.
>WTF is "Thunderbird"?
It's a low-cost liquid refreshment concocted to fuel exactly the type
of thinking and writing we've come to expect of you. See
http://www.bumwine.com/tbird.html.
Wayne
Solar Flare
get rid of on some of our equipment. Too high a S/S+N ratio and cause
a distorted sense of potential.
"wmbjk" <wmbjk...@citlink.net> wrote in message
news:g89gn2hgdukqr1h2s...@4ax.com...
Solar Flare
statements made doesn't excuse your confusion.
"Ron Rosenfeld" <ronros...@nospam.org> wrote in message
news:162gn29rithsssbhr...@4ax.com...
wmbjk
<solae...@hootmail.invalidated> wrote:
>Just as I figured. You are like the third harmonic we are trying to
>get rid of on some of our equipment. Too high a S/S+N ratio and cause
>a distorted sense of potential.
And yet just yesterday you were happy to have my advice, and thankful
for the help. I take it that the pace of your "research" into the
MX60i has slowed? Too funny.
Wayne