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Li-ion UPS battery substitution in UPS

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Bert Hickman

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Oct 18, 2022, 11:43:44 AM10/18/22
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Does anyone have any experience swapping out old lead-acid batteries for
Li-ion equivalents in a UPS?

I see these batteries advertised as replacements, but I'm concerned about
their safety in this application. New Li-ion UPS systems seem to be
extremely expensive.

Ricky

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Oct 18, 2022, 11:50:14 AM10/18/22
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I've seen the charging methods indicated as being similar, constant current, constant voltage, then a topping charge. But lithium ion batteries do not tolerate a float charge. Even if this wasn't an issue, the details of current and voltage will not be the same. I would not expect the lithium batteries to live very long being charged as lead acid.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

Ed Lee

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Oct 18, 2022, 11:51:04 AM10/18/22
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I added some Li cells to my dying LA battery. Yes, there is LA in EV. However, i have to be careful not to over-charge it for extended period of time. I disconnect it during extended usage, when the LA can handle the load. Unlike LA, Li does not like to be fully charged.

Lasse Langwadt Christensen

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Oct 18, 2022, 12:05:08 PM10/18/22
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might look at LiFe4 instead, afaik you can get LiFe4 car batteries so they must be reasonably compatible

LiFe4 should also be bit safer the Li-ion

Ed Lee

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Oct 18, 2022, 12:11:53 PM10/18/22
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Yes, i use 4S (3.2V x 4) LiFePO4 and 3S (3.7V x 3) LiPo.

Ed Lee

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Oct 18, 2022, 12:34:43 PM10/18/22
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BTW, i am using some old 12V module based on the TI BQ20Z95 and some new one based on BQ20Z65. Half of the BQ20Z95 doesn't work or cut-off at low 11V. BQ20Z65 works better, but still cut-off at around 11.5V or sometimes lower, even with all new cells.

For emergency, i put 32 to 34 of them in series to run at 400V.

a a

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Oct 18, 2022, 1:23:47 PM10/18/22
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LiFe4 car batteries is old fake promoted by traders, which has never worked fine.

LiFe4 is still Li-ion battery and should be avoided to not risk fire in your car.

My friend offered me 80 used LiFe4 90Ah car batteries from his electric car, affected by pillow syndrome
but I rejected to not risk my home demolished one day.

Ed Lee

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Oct 18, 2022, 1:28:12 PM10/18/22
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On Tuesday, October 18, 2022 at 10:23:47 AM UTC-7, a a wrote:
> On Tuesday, 18 October 2022 at 18:05:08 UTC+2, lang...@fonz.dk wrote:
> > tirsdag den 18. oktober 2022 kl. 17.43.44 UTC+2 skrev Bert Hickman:
> > > Does anyone have any experience swapping out old lead-acid batteries for
> > > Li-ion equivalents in a UPS?
> > >
> > > I see these batteries advertised as replacements, but I'm concerned about
> > > their safety in this application. New Li-ion UPS systems seem to be
> > > extremely expensive.
> > might look at LiFe4 instead, afaik you can get LiFe4 car batteries so they must be reasonably compatible
> >
> > LiFe4 should also be bit safer the Li-ion
> LiFe4 car batteries is old fake promoted by traders, which has never worked fine.
>
> LiFe4 is still Li-ion battery and should be avoided to not risk fire in your car.

Yes, you need good BMS and manual disconnect.

> My friend offered me 80 used LiFe4 90Ah car batteries from his electric car, affected by pillow syndrome
> but I rejected to not risk my home demolished one day.

Tell him to put it on ebay and give me a link here. I might get them if the price is right.

a a

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Oct 18, 2022, 1:53:36 PM10/18/22
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Better turn your electric car into mobile 100 kWh UPS

Ed Lee

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Oct 18, 2022, 2:01:32 PM10/18/22
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Mine is essentially Li UPS. LA is too heavy.

Ed Lee

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Oct 18, 2022, 2:20:03 PM10/18/22
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BTW, my 12V to 400V DC/DC converter is 100% efficient.

Don Y

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Oct 18, 2022, 5:10:35 PM10/18/22
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I wouldn't trust them -- unless the UPS manufacturer had blessed them
(and dubious, even then).

If you are having problems with battery life in UPS, look to see
how it is being charged. Many "cook" their batteries (poor
circuit tolerances). Also, they seem intent on recharging QUICKLY
(in case another outage??) instead of trying to prolong the batteries'
service life.

Finally, note that many places will pay you for the lead in
your old batteries. If you're just using 12V7.2AHr batteries,
then there's not much money there (~$0.20/pound). OTOH, if
you have a bigger UPS, you can get a fair bit back (I got
over $100 for the dead batteries in my biggest UPS)

a a

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Oct 18, 2022, 6:24:13 PM10/18/22
to
Never recycle used UPS gel batteries
since installed to operate in serial string, can crash if a single gel battery crashes,
so the rest can still be fit for home use.

The same works for laptop batteries
2P 3S Battery crashes but you can still recover 2 or 4 pieces if not left uncharged for a long time

Robert Roland

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Oct 19, 2022, 5:03:37 AM10/19/22
to
On Tue, 18 Oct 2022 10:43:25 -0500, Bert Hickman
<be...@capturedlightning.com> wrote:

>Does anyone have any experience swapping out old lead-acid batteries for
>Li-ion equivalents in a UPS?

Why would you want to? There are several parameters to consider.

Li batteries age quite fast if kept at full charge. Lead-Acid
batteries last the longest when kept at full charge.

LA's biggest disadvantages, compared to Li, is that they are heavy and
large. For a UPS, those disadvantages are normally not important.

LA is simply the best choice for standby applications such as UPS,
emergency ligting and similar.
--
RoRo

a a

unread,
Oct 19, 2022, 5:52:37 AM10/19/22
to
wrong
in your car you use exactly: lead-acid batteries
but you don't use car lead-acid batteries in UPS
since in UPS you use Gel batteries

John Walliker

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Oct 19, 2022, 6:01:40 AM10/19/22
to
But those gel batteries ARE lead acid! They just have the gel
to hold the acid in place along with catalysts to aid
recombination of evolved gas.
Some car batteries are gel or glass mat types.
However, LiFePO4 batteries do seem to avoid most of the problems
of original Li ion batteries. Tesla are now using them in most of
their cars. Ford and VW are planning to do the same.
John

a a

unread,
Oct 19, 2022, 6:23:59 AM10/19/22
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exactly, but they are not fit for your car as car battery

My friend offered me 80 used LiFePO4 batteries from his electric car made in Italy
and I simply rejected not being interested to go into problems with charging them individually at home for 2 months

What is safe and called electric car outdoor charging
is not exactly safe while arranged indoor, at your home.

It m ay take another 10 years to get LiFePO4 batteries to replace standard Lea-Acid car batteries.

Ideas by Elon don't make the world

LiFePO4 batteries are affected by pillow syndrome so not fit to be installed in tigh compartment in your car

Ed Lee

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Oct 19, 2022, 6:34:31 AM10/19/22
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Good BMSs stop over-charging and under-discharging. Good EVs don't have pillows.

legg

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Oct 21, 2022, 7:27:10 PM10/21/22
to
On Tue, 18 Oct 2022 10:43:25 -0500, Bert Hickman
<be...@capturedlightning.com> wrote:

Go for LiFePO4 (lithium iron), but only if the firmware is
updated to allow for proper charge termination and voltage
settings.

A capacitive balancing circuit is a good idea.

RL

Fred Bloggs

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Oct 21, 2022, 8:51:30 PM10/21/22
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Do you really think the modern lithium battery is just a dumb collection of cells. The products going after the SLA market almost certainly have built-in BMS ( battery management system) that cuts off the charging current when fully charged. And that BMS is probably made by Analog Devices. Last time I looked the charge management cuts off the float mode charge current when it has fallen to 25% or so of the initial Ipk delivered to the uncharged battery. And there's a sensitivity of 100:1 state of charge to the temperature dependent open terminal voltage, so the process requires great precision. Nonetheless, it's simple to very reliably put the lithium into the SLA charge circuit- within reason.

Fred Bloggs

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Oct 21, 2022, 8:53:30 PM10/21/22
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Looks like a lot of people never got the memo because lithium is about all you see in standby applications these days. That doesn't mean it's right, it just means that's what just about everybody is doing.

> --
> RoRo

Fred Bloggs

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Oct 21, 2022, 9:15:25 PM10/21/22
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You could most certainly use wet cell lead acid in the UPS if you're not afraid of spillage and explosion hazards.

The ultimate lead acid batteries are the AGM. You see them used a lot in solar backup applications, the reason being they can withstand very deep discharge that would destroy a lesser battery. There are automotive versions available too, and they cost top dollar, as in ???x ( changes all the time, price is coming down though) the ordinary battery, last time I checked. In addition to surviving deep discharge, they pack a helluva wallop peak current. That's why they're the battery of choice in all those compact car starter accessories you see for sale.

Don Y

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Oct 21, 2022, 9:39:16 PM10/21/22
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Do you really think a UPS treats a battery as an ideal voltage source?

Do you really think a product designed years ago can just tolerate
a replacement battery chemistry? That the charger isn't actively
monitoring charge current? And determining state of charge by
noticing its relationship to open cell voltage over time?

How do you think the UPS decides that the battery needs replacing?

"Gee, battery stopped taking charge current. Has it become disconnected?
Has it failed?"

Why are lithium based solutions MULTIPLES of the price of lead-acid
solutions? Surely they could just take an EXISTING lead acid design
and drop in a "lead-acid emulator" for the incremental cost of the
"emulator battery" over the lead-acid original.

Maybe there's more to the technology than you think!

John Walliker

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Oct 22, 2022, 3:52:43 AM10/22/22
to
Not in mine. It uses lithium cells, is easy to hold in one hand and has started
a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
about Li cells is that the starter pack can sit on the shelf for a year without any
attention and then "just work". (I do leave it slightly discharged to help preserve
battery life.) It was very reasonably priced about 3 years ago, mostly because
I bought it on an Amazon "flash" sale. I had been browsing for such things but
considered all the good ones to be too expensive. Then an offer of a 40% discount,
valid for 1 hour, popped up and I took it.

John

Don Y

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Oct 22, 2022, 4:06:33 AM10/22/22
to
On 10/22/2022 12:52 AM, John Walliker wrote:
> Not in mine. It uses lithium cells, is easy to hold in one hand and has started
> a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
> about Li cells is that the starter pack can sit on the shelf for a year without any
> attention and then "just work". (I do leave it slightly discharged to help preserve
> battery life.) It was very reasonably priced about 3 years ago, mostly because
> I bought it on an Amazon "flash" sale. I had been browsing for such things but
> considered all the good ones to be too expensive. Then an offer of a 40% discount,
> valid for 1 hour, popped up and I took it.

But is *it* really starting the car *or* simply quickly replenishing
(topping off) the charge in the existing lead acid battery? I.e.,
converting "unusable" coulombs to useful ones?

Most of the units I've seen have ~16AWG leads -- hardly enough to
carry the current required to turn over the engine.

Said another way, if the lead-acid battery was REMOVED from the car,
would you expect to be able to turn it over?

John Walliker

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Oct 22, 2022, 6:42:01 AM10/22/22
to
I think it varied according to which vehicle. A couple of weeks ago I used it
every time I started the engine (1.8l petrol) of my car because the car battery had
developed a very high internal resistance and probably also had a shorted cell.
The voltage dropped to 6V on trying (and failing) to crank the engine. The
charging voltage was only about 12.5V. With the Li starter pack the engine would
start immediately. I have now replaced the battery.
In the case of the Ferrari FF (not mine, sadly) the battery was completely dead and
it took many attempts to get it started with the Li starter pack, so the Li battery
really was doing all the work. However, this was a 6.3 litre, 650HP V12 engine.
It did start in the end. Its battery accepted no charge whatsoever - it would not
even run its lights after a 20 minute drive.
In the case of the diesel van, it may well have added just enough charge to make
a difference in the 20 seconds or so between connecting it and starting the engine.
My unit has very short, very thick (6AWG) cables:

no.co/gb70

Usefully, it also has a regulated 12Vdc output.

John

Don Y

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Oct 22, 2022, 8:07:59 AM10/22/22
to
That's considerably beefier than the units I've seen -- which looked more
like DMMs with dinky little (thin) leads (shirt-pocket sized)! Hence my
suspicion that they were just (rapidly) topping off a depleted battery.


Fred Bloggs

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Oct 22, 2022, 9:34:30 AM10/22/22
to
Not really. I don't care what kind of battery charge management the UPS has, the replacement battery can be made to look identical to the original. Cutting off the charge current in float mode does not mean opening a relay switch or something crude like that. The replacement battery can present enough of a self-discharge current loading to make itself look real enough.

Ed Lee

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Oct 22, 2022, 10:18:38 AM10/22/22
to
On Saturday, October 22, 2022 at 1:06:33 AM UTC-7, Don Y wrote:
> On 10/22/2022 12:52 AM, John Walliker wrote:
> > Not in mine. It uses lithium cells, is easy to hold in one hand and has started
> > a variety of large engines including diesel vans and a Ferrari FF. One of the nice things
> > about Li cells is that the starter pack can sit on the shelf for a year without any
> > attention and then "just work". (I do leave it slightly discharged to help preserve
> > battery life.) It was very reasonably priced about 3 years ago, mostly because
> > I bought it on an Amazon "flash" sale. I had been browsing for such things but
> > considered all the good ones to be too expensive. Then an offer of a 40% discount,
> > valid for 1 hour, popped up and I took it.
> But is *it* really starting the car *or* simply quickly replenishing
> (topping off) the charge in the existing lead acid battery? I.e.,
> converting "unusable" coulombs to useful ones? .

My Leaf won't wakeup after 2 or 3 days sleeping. It's mostly because of the 100W power relay. I could just jumper short the relay output, when i open up the battery next time. For now, i just added a 200Wh (3S9P) Li power brick (around 5 pounds) to the LA battery. The Li BMS cutoff at 11.5V when charging. It's fine in this case. The Li battery mostly keep the LA battery from dropping too low.

> Most of the units I've seen have ~16AWG leads -- hardly enough to
> carry the current required to turn over the engine.
>
> Said another way, if the lead-acid battery was REMOVED from the car,
> would you expect to be able to turn it over?

Yes it does. But better to keep the LA when close to fully charge, and less cycling on the Li.

Don Y

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Oct 22, 2022, 11:16:46 AM10/22/22
to
And, you'll discover on one UPS the UPS won't turn on because it doesn't
see a battery; on another, it won't run it's self checks; etc. You don't
know what "firmware A" expects of it's battery that "firmware B" doesn't.

All of the battery-backed products I've designed predated lithium. Put
a lithium battery in them and they'll throw a fault -- because the
battery isn't discharging at the expected rate; or is charging at
the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.

"Hey, let's make this lithium battery look EXACTLY like a lead acid -- so
it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
for those non-differences!"

MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W>
MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX>

$1000 premium for lithium battery pack. Same exact run-times,
same load capacity, same networking capability, same display
(literally the same module). Ah, but the more expensive one has
a shiny front panel (and isn't intended to be floor-standing)!

[Latter has shallower aspect ratio and weighs less -- though at the cost
of an additional rack unit. *Might* be important in a datacenter;
doubtful a SOHO user would bother with it as he'd likely not have
many such devices, many batteries to replace, etc. Note the number
of lead-acid offerings vs. lithium -- why is that?]

Ed Lee

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Oct 22, 2022, 2:19:58 PM10/22/22
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1500VA or 100Wh? See first comment. That's certainly expensive. I can get 100Wh for $28.9999

Fred Bloggs

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Oct 22, 2022, 5:05:28 PM10/22/22
to
You're becoming hysterical. Batteries are not precision components. Any design that's looking at voltage time drift or charge rates to make any decisions is deluding itself. All you end up doing is set up the user for quirky indications they'll just learn to ignore.

Ed Lee

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Oct 22, 2022, 5:24:40 PM10/22/22
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Charge rate is no big deal. A small 18650 can take up to 3A to 5A charging. Voltage is more important. My eTank #2 is 34x 3S batteries without BMS. Typical EV equivalence is 32x, which run the cells between 3.5V to 4.2V. I run mine at 34x with cells between 3V and 4V. I check and balance them manually. No pillows and/or firecrackers yet.

My eTank #3 will have EMS.

Don Y

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Oct 22, 2022, 5:29:19 PM10/22/22
to
Hysterical? Wow, you've sure got a perverse sense of reality!

> Batteries are not precision components. Any
> design that's looking at voltage time drift or charge rates to make any
> decisions is deluding itself. All you end up doing is set up the user for
> quirky indications they'll just learn to ignore.

I guess products that have done so and are in the field, WITHOUT COMPLAINT,
must not exist in your perverse reality!

Designs that just look at voltage trip points are the ones that
annoy users with erroneous data.

If I dump C/10 into a battery pack FOR TWELVE HOURS and see no change in
pack voltage, is that just a quirk? What about three hours? One hour?
Maybe I should just wait a week and, at the end of the week, the cell
voltage will spontaneously indicate a full charge?

Despite the fact that, HISTORICALLY (remember, I can watch the battery
FOREVER; it's built into the circuit!) it has registered a specific change
in each of those intervals?

If I'm a constant load and, today, see the pack voltage dropping at rate R1
and, historically, it has always dropped at ~R0 (R0 << R1), should I just
assume that's a quirk and NOT act on it? Has my implementation ACTUALLY
changed so that the components are dissipating more power -- yet NOTHING
IS WRONG?

We EXPECT components to behave in largely predictable ways. Otherwise,
we couldn't design with them.


Fred Bloggs

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Oct 22, 2022, 5:46:40 PM10/22/22
to
Sounds like you're confusing predictability with eternality. Talk about oversimplification. The measurements you touched on are largely a big unknown, not only in principle but in practice. Any instance of a particular battery is more than just the battery itself but also it's entire life history of charge and discharge cycles, storage temperature, maybe a bunch of other stuff known to have significant impact on battery life. Did you do any pulsed impedance measurements with varying test loading while you were at it. IIRC the terminal impedance tells some people a lot about the battery condition.

Don Y

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Oct 22, 2022, 5:48:47 PM10/22/22
to
On 10/22/2022 11:19 AM, Ed Lee wrote:
>>>> Maybe there's more to the technology than you think!
>>>
>>> Not really. I don't care what kind of battery charge management the UPS has,
>>> the replacement battery can be made to look identical to the original.
>>> Cutting off the charge current in float mode does not mean opening a relay
>>> switch or something crude like that. The replacement battery can present
>>> enough of a self-discharge current loading to make itself look real enough.
>> And, you'll discover on one UPS the UPS won't turn on because it doesn't
>> see a battery; on another, it won't run it's self checks; etc. You don't
>> know what "firmware A" expects of it's battery that "firmware B" doesn't.
>>
>> All of the battery-backed products I've designed predated lithium. Put
>> a lithium battery in them and they'll throw a fault -- because the
>> battery isn't discharging at the expected rate; or is charging at
>> the wrong rate (dv/dt); or, the monitoring circuitry appears defective; etc.
>>
>> "Hey, let's make this lithium battery look EXACTLY like a lead acid -- so
>> it HAS NO ADVANTAGES over a lead acid battery! But, we can charge more
>> for those non-differences!"
>>
>> MSRP $1,865.88 <https://www.amazon.com/dp/B08QQRFQ4W>
>> MSRP $2,899.99 <https://www.amazon.com/dp/B09JR6ZCQX>
>
> 1500VA or 100Wh? See first comment. That's certainly expensive. I can get 100Wh for $28.9999

1500VA load capacity. Run time (for each) is 5 minutes at full load
(about 13 minutes at half load -- though the lead acid unit will go
almost 15 minutes). I have several of the first unit that I use
to power my "bench tops" (anything located *on* my bench vs. UNDER).

My point is, they could have taken the existing LA design and just
put lithium batteries in it, if there was no other consequence to
changing the battery chemistry. After all, they allegedly "look
just like lead acid", right? :> And, other than longevity and
power density, they offer no better *performance* in this example
(in practical terms: run time!)

My experience (processing LITERALLY *thousands* of discarded UPSs
that are still operational -- except for their batteries) has been
that folks think they need a UPS. And, later, decide they aren't
worth the trouble. Mains power, in most places, is pretty
reliable. Outages infrequent. And, systems (except life support)
tend to be reasonably robust in limiting loss due to abrupt
outages.

[Think about it; do you really do any work during an outage?
This machine -- and the modem -- have an oversized backup
that will keep them operational for a couple of hours. But,
every other machine just needs to stay "up" until I can get
around to noting what they were doing, at the time of the outage,
and cleanly shutting them down -- before the UPS daemon does
that unilaterally]

Most of the 12 (15?) UPSs that I have here were rescued NIB;
many with functional battery packs (some happened to have been
warehoused too long before being discarded). Anything with bad
batteries has a (recycle) value of about $5 -- largely for the
weight of the switching transformer (plastic has NO value and
the tin/steel case is $0.01/pound; circuit boards have very little
precious metals so pennies, there).

[An unattended workstation is typically idle and the disk cache has
already been written out so you're only concerned with outages
WHILE you are actively working on something.]

Hence my points to the OP. Think about WHY you are looking at lithium
pack replacements (they are roughly double the price of lead acid;
is the inconvenience of replacing them every three or four years
really worth the price? Are you sure you won't be replacing (or
discarding!) the UPS in that same interval??

[I see a market for oversized "super caps"; temporary energy reservoirs
to let UPSs ride out very short outages -- a second or two -- without
the need for replacement]

Don Y

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Oct 22, 2022, 5:53:30 PM10/22/22
to
On 10/22/2022 7:18 AM, Ed Lee wrote:
> On Saturday, October 22, 2022 at 1:06:33 AM UTC-7, Don Y wrote:
>> On 10/22/2022 12:52 AM, John Walliker wrote:
>>> Not in mine. It uses lithium cells, is easy to hold in one hand and has
>>> started a variety of large engines including diesel vans and a Ferrari
>>> FF. One of the nice things about Li cells is that the starter pack can
>>> sit on the shelf for a year without any attention and then "just work".
>>> (I do leave it slightly discharged to help preserve battery life.) It
>>> was very reasonably priced about 3 years ago, mostly because I bought it
>>> on an Amazon "flash" sale. I had been browsing for such things but
>>> considered all the good ones to be too expensive. Then an offer of a 40%
>>> discount, valid for 1 hour, popped up and I took it.
>> But is *it* really starting the car *or* simply quickly replenishing
>> (topping off) the charge in the existing lead acid battery? I.e.,
>> converting "unusable" coulombs to useful ones? .
>
> My Leaf won't wakeup after 2 or 3 days sleeping. It's mostly because of the
> 100W power relay.

Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?
Why isn't the resting state of the relay the one that doesn't draw
power? Does an additional 100W "driving load" hurt your efficiency
that much that it has to be moved to the "charging" state?

> I could just jumper short the relay output, when i open
> up the battery next time. For now, i just added a 200Wh (3S9P) Li power
> brick (around 5 pounds) to the LA battery. The Li BMS cutoff at 11.5V when
> charging. It's fine in this case. The Li battery mostly keep the LA
> battery from dropping too low.

So, you're just using the lithium battery to keep the leaky lead acid
battery "topped off". Could that brick achieve the same purpose if
connected to the battery via a pushbutton that you momentarily activate
prior to starting the vehicle? (Or, is the LA battery your main propulsion
battery pack)

Don Y

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Oct 22, 2022, 6:03:52 PM10/22/22
to
No. You're overcomplicating things! You want dimensioned values for
observations; I just want *trends*.

I don't care what the rate of current flow out of the battery is FOR
THIS DEVICE. I know the nominal design rate and have selected the battery
with that in mind. Nor do I care how "robust" this particular battery
happens to be -- it may have been sitting on a shelf in the stockroom
a few months longer than some other battery. Or, the specific gravity
of the electrolyte may be at the other end of the manufacturer's tolerance.

The *user* only cares about:
- how long will the unit remain operational in the absence of power
(will I be able to finish the uninterruptible process that I have
begun before it unilaterally shuts down?)
- how long will the battery continue to provide this level of
performance before requiring replacement

As the battery is continuously observable, I can make those predictions
FOR THIS BATTERY IN THIS DEVICE.

You WATCH THE BATTERY. FOREVER. You TAKE NOTES. You don't care if it
performs identically to every other battery. Rather, you notice how THIS
battery performs in THIS circuit with THESE tolerances in THESE
environmental conditions. You expect it to perform roughly the same,
tomorrow. And, you expect its performance to gradually degrade up to
a point where it fails to meet the design goals.

BEFORE it gets to that point (and pisses off the user), you alert the user
to that fact.

When the battery is replaced, you restart the observation process anew.

And, you didn't have to incur additional manufacturing test or calibration
steps to provide this information!

Ed Lee

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Oct 22, 2022, 6:05:28 PM10/22/22
to
On Saturday, October 22, 2022 at 2:53:30 PM UTC-7, Don Y wrote:
> On 10/22/2022 7:18 AM, Ed Lee wrote:
> > On Saturday, October 22, 2022 at 1:06:33 AM UTC-7, Don Y wrote:
> >> On 10/22/2022 12:52 AM, John Walliker wrote:
> >>> Not in mine. It uses lithium cells, is easy to hold in one hand and has
> >>> started a variety of large engines including diesel vans and a Ferrari
> >>> FF. One of the nice things about Li cells is that the starter pack can
> >>> sit on the shelf for a year without any attention and then "just work".
> >>> (I do leave it slightly discharged to help preserve battery life.) It
> >>> was very reasonably priced about 3 years ago, mostly because I bought it
> >>> on an Amazon "flash" sale. I had been browsing for such things but
> >>> considered all the good ones to be too expensive. Then an offer of a 40%
> >>> discount, valid for 1 hour, popped up and I took it.
> >> But is *it* really starting the car *or* simply quickly replenishing
> >> (topping off) the charge in the existing lead acid battery? I.e.,
> >> converting "unusable" coulombs to useful ones? .
> >
> > My Leaf won't wakeup after 2 or 3 days sleeping. It's mostly because of the
> > 100W power relay.
> Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?

No, 100W when the car is on. After a few days, the 12V battery is too weak to pull the 100W power relay (switching 400V on).

> Why isn't the resting state of the relay the one that doesn't draw
> power? Does an additional 100W "driving load" hurt your efficiency
> that much that it has to be moved to the "charging" state?
> > I could just jumper short the relay output, when i open
> > up the battery next time. For now, i just added a 200Wh (3S9P) Li power
> > brick (around 5 pounds) to the LA battery. The Li BMS cutoff at 11.5V when
> > charging. It's fine in this case. The Li battery mostly keep the LA
> > battery from dropping too low.
> So, you're just using the lithium battery to keep the leaky lead acid
> battery "topped off". Could that brick achieve the same purpose if
> connected to the battery via a pushbutton that you momentarily activate
> prior to starting the vehicle? (Or, is the LA battery your main propulsion
> battery pack)

Yes, i also did an emergency jump charging from 400V to 12V with 5S5P 200K resistor. Not very efficient, but works and i happened to have the resistors in the car, and 400V tap in the backseat. The traction/propulsion battery is 24kWh 96S Li.

Don Y

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Oct 22, 2022, 6:28:07 PM10/22/22
to
On 10/22/2022 3:05 PM, Ed Lee wrote:
>>> My Leaf won't wakeup after 2 or 3 days sleeping. It's mostly because of
>>> the 100W power relay.
>> Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?
>
> No, 100W when the car is on. After a few days, the 12V battery is too weak
> to pull the 100W power relay (switching 400V on).

Is there a parasitic drain on that battery? Or, is it just undersized
for the task? (one would expect a car sitting for 2 or 3 days to be
somewhat "normal use")

>> Why isn't the resting state of the relay the one that doesn't draw power?
>> Does an additional 100W "driving load" hurt your efficiency that much that
>> it has to be moved to the "charging" state?
>>> I could just jumper short the relay output, when i open up the battery
>>> next time. For now, i just added a 200Wh (3S9P) Li power brick (around 5
>>> pounds) to the LA battery. The Li BMS cutoff at 11.5V when charging.
>>> It's fine in this case. The Li battery mostly keep the LA battery from
>>> dropping too low.
>> So, you're just using the lithium battery to keep the leaky lead acid
>> battery "topped off". Could that brick achieve the same purpose if
>> connected to the battery via a pushbutton that you momentarily activate
>> prior to starting the vehicle? (Or, is the LA battery your main
>> propulsion battery pack)
>
> Yes, i also did an emergency jump charging from 400V to 12V with 5S5P 200K
> resistor. Not very efficient, but works and i happened to have the
> resistors in the car, and 400V tap in the backseat. The traction/propulsion
> battery is 24kWh 96S Li.

This suggests either replacing the battery with something with less
leakage/more reserve (assuming there is no unintentional leak)
or just installing the lithium battery as a built-in jump starter.

Though your approach suggests you don't have to worry about
keeping the lithium charged if permanently installed (?)

Ed Lee

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Oct 22, 2022, 6:37:13 PM10/22/22
to
On Saturday, October 22, 2022 at 3:28:07 PM UTC-7, Don Y wrote:
> On 10/22/2022 3:05 PM, Ed Lee wrote:
> >>> My Leaf won't wakeup after 2 or 3 days sleeping. It's mostly because of
> >>> the 100W power relay.
> >> Are you saying that the relay actuator dissipates 100W WHILE SLEEPING?
> >
> > No, 100W when the car is on. After a few days, the 12V battery is too weak
> > to pull the 100W power relay (switching 400V on).
> Is there a parasitic drain on that battery? Or, is it just undersized
> for the task? (one would expect a car sitting for 2 or 3 days to be
> somewhat "normal use")

Just old age. The battery is 10 years old. The solar charger is probably dead also, or not enough sun in SF.

> >> Why isn't the resting state of the relay the one that doesn't draw power?
> >> Does an additional 100W "driving load" hurt your efficiency that much that
> >> it has to be moved to the "charging" state?
> >>> I could just jumper short the relay output, when i open up the battery
> >>> next time. For now, i just added a 200Wh (3S9P) Li power brick (around 5
> >>> pounds) to the LA battery. The Li BMS cutoff at 11.5V when charging.
> >>> It's fine in this case. The Li battery mostly keep the LA battery from
> >>> dropping too low.
> >> So, you're just using the lithium battery to keep the leaky lead acid
> >> battery "topped off". Could that brick achieve the same purpose if
> >> connected to the battery via a pushbutton that you momentarily activate
> >> prior to starting the vehicle? (Or, is the LA battery your main
> >> propulsion battery pack)
> >
> > Yes, i also did an emergency jump charging from 400V to 12V with 5S5P 200K
> > resistor. Not very efficient, but works and i happened to have the
> > resistors in the car, and 400V tap in the backseat. The traction/propulsion
> > battery is 24kWh 96S Li.
> This suggests either replacing the battery with something with less
> leakage/more reserve (assuming there is no unintentional leak)
> or just installing the lithium battery as a built-in jump starter.
>
> Though your approach suggests you don't have to worry about
> keeping the lithium charged if permanently installed (?)

Yes, the Li power brick is essentially a built-in automatic jump starter. It's around $28 including shipping, but with more capacity than the $2899 UPS.

Don Y

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Oct 22, 2022, 7:06:17 PM10/22/22
to
On 10/22/2022 3:37 PM, Ed Lee wrote:
> On Saturday, October 22, 2022 at 3:28:07 PM UTC-7, Don Y wrote:
>> On 10/22/2022 3:05 PM, Ed Lee wrote:
>>>>> My Leaf won't wakeup after 2 or 3 days sleeping. It's mostly because
>>>>> of the 100W power relay.
>>>> Are you saying that the relay actuator dissipates 100W WHILE
>>>> SLEEPING?
>>>
>>> No, 100W when the car is on. After a few days, the 12V battery is too
>>> weak to pull the 100W power relay (switching 400V on).
>> Is there a parasitic drain on that battery? Or, is it just undersized for
>> the task? (one would expect a car sitting for 2 or 3 days to be somewhat
>> "normal use")
>
> Just old age. The battery is 10 years old. The solar charger is probably
> dead also, or not enough sun in SF.

Oh. You know you *can* buy a replacement battery! :>
Are you sure about that? E.g., I doubt the battery has MUCH effect on
the efficiency of the UPS. Both units claim the same load capacity and
run-time -- so, likely have the same "reserve energy capacity".

Mine (the lead acid unit) has a 350WHr battery pack (48V @ 7.2AHr)
so I would assume the lithium variant is comparable.

Regardless, they serve different functions. Does your starter
provide a 120V 60Hz waveform that you can use to power a household
appliance? <grin>

I think the lithium units are attractive in data centers where
size and weight are important. SOHO users don't care how much
(of either) their solutions entail. They likely have one (or
"a few") unit and find a way of "accommodating it".

Data centers can have dozens to hundreds -- each trying to keep a
load "up" long enough for the genset to kick in. Lead acid battery
packs are heavy (think total weight on the floor supports for
the data center as well as the human hassle of sliding the UPS out
on its rails for service/replacement)

SOHO users likely have more accessible spaces -- man-handle the UPS
to a spot where you can open it up *or* remove it. Mine are sited
under my workbenches -- which is great for keeping them out of the
way (sub-prime real estate). But, a nuisance when it comes to
plugging/unplugging loads! (SWMBO would roll her eyes watching me
attempt to thread my body OVER a disk array -- to heavy to move! -- to
get access to the back panel of the adjacent UPS. The empirically
discovered solution is to MOVE THE UPS's OUTLETS to a more
accessible location while keeping the UPS happy where it is!)

(sigh) Oh what it would be like to have a BASEMENT!!! :<

Ed Lee

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Oct 22, 2022, 7:20:48 PM10/22/22
to
My Li brick is 300WHr new (perhaps 250WHr used). 12V @ 27AHr

> Regardless, they serve different functions. Does your starter
> provide a 120V 60Hz waveform that you can use to power a household
> appliance? <grin>

With an inverter, I can power a labtop for at least an hour, or 32 of them for a day.

Don Y

unread,
Oct 22, 2022, 7:28:03 PM10/22/22
to
On 10/22/2022 4:20 PM, Ed Lee wrote:
>>> Yes, the Li power brick is essentially a built-in automatic jump starter.
>>> It's around $28 including shipping, but with more capacity than the $2899
>>> UPS.
>> Are you sure about that? E.g., I doubt the battery has MUCH effect on
>> the efficiency of the UPS. Both units claim the same load capacity and
>> run-time -- so, likely have the same "reserve energy capacity".
>>
>> Mine (the lead acid unit) has a 350WHr battery pack (48V @ 7.2AHr)
>> so I would assume the lithium variant is comparable.
>
> My Li brick is 300WHr new (perhaps 250WHr used). 12V @ 27AHr

So, a bit smaller than what's in the UPS (if we assume similar
efficiencies for the lead acid and lithium inverters)

>> Regardless, they serve different functions. Does your starter
>> provide a 120V 60Hz waveform that you can use to power a household
>> appliance? <grin>
>
> With an inverter, I can power a labtop for at least an hour, or 32 of them for a day.

Yeah, and with 4 wheels and a lightweight chassis, I could ride around
the block! :>

Gotta wonder why they aren't buying inverters and "battery jumpstarters"
to power their data centers, eh?

Ed Lee

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Oct 22, 2022, 7:31:43 PM10/22/22
to
On Saturday, October 22, 2022 at 4:28:03 PM UTC-7, Don Y wrote:
> On 10/22/2022 4:20 PM, Ed Lee wrote:
> >>> Yes, the Li power brick is essentially a built-in automatic jump starter.
> >>> It's around $28 including shipping, but with more capacity than the $2899
> >>> UPS.
> >> Are you sure about that? E.g., I doubt the battery has MUCH effect on
> >> the efficiency of the UPS. Both units claim the same load capacity and
> >> run-time -- so, likely have the same "reserve energy capacity".
> >>
> >> Mine (the lead acid unit) has a 350WHr battery pack (48V @ 7.2AHr)
> >> so I would assume the lithium variant is comparable.
> >
> > My Li brick is 300WHr new (perhaps 250WHr used). 12V @ 27AHr
> So, a bit smaller than what's in the UPS (if we assume similar
> efficiencies for the lead acid and lithium inverters)

But for less than $28. How much is your UPS?

> >> Regardless, they serve different functions. Does your starter
> >> provide a 120V 60Hz waveform that you can use to power a household
> >> appliance? <grin>
> >
> > With an inverter, I can power a labtop for at least an hour, or 32 of them for a day.
> Yeah, and with 4 wheels and a lightweight chassis, I could ride around
> the block! :>
>
> Gotta wonder why they aren't buying inverters and "battery jumpstarters"
> to power their data centers, eh?

It's essentially the same inside, just package better for data centers.

Don Y

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Oct 22, 2022, 7:47:17 PM10/22/22
to
On 10/22/2022 4:31 PM, Ed Lee wrote:
> On Saturday, October 22, 2022 at 4:28:03 PM UTC-7, Don Y wrote:
>> On 10/22/2022 4:20 PM, Ed Lee wrote:
>>>>> Yes, the Li power brick is essentially a built-in automatic jump starter.
>>>>> It's around $28 including shipping, but with more capacity than the $2899
>>>>> UPS.
>>>> Are you sure about that? E.g., I doubt the battery has MUCH effect on
>>>> the efficiency of the UPS. Both units claim the same load capacity and
>>>> run-time -- so, likely have the same "reserve energy capacity".
>>>>
>>>> Mine (the lead acid unit) has a 350WHr battery pack (48V @ 7.2AHr)
>>>> so I would assume the lithium variant is comparable.
>>>
>>> My Li brick is 300WHr new (perhaps 250WHr used). 12V @ 27AHr
>> So, a bit smaller than what's in the UPS (if we assume similar
>> efficiencies for the lead acid and lithium inverters)
>
> But for less than $28. How much is your UPS?

But you've only replaced the BATTERY in my UPS. Do you have a network
connection that lets me control your device? And, provide status reports
as to the size of the load, battery state, etc. periodically as well as
via a front panel display?

Is it rack mountable? Does it carry any sort of warranty and
protections against damaging the equipment it powers? UL approved?
etc.

[You'll note -- from previous post -- that my UPSs were $5/each]

You're addressing a different problem.