Li-ion UPS battery substitution in UPS

[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.

[Ricky]

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]

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]

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]

Yes, i use 4S (3.2V x 4) LiFePO4 and 3S (3.7V x 3) LiPo.

[Ed Lee]

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]

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]

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]

Better turn your electric car into mobile 100 kWh UPS

[Ed Lee]

Mine is essentially Li UPS. LA is too heavy.

[Ed Lee]

BTW, my 12V to 400V DC/DC converter is 100% efficient.

[Don Y]

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]

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]

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]

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]

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]

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]

Good BMSs stop over-charging and under-discharging. Good EVs don't have pillows.

[legg]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

1500VA or 100Wh? See first comment. That's certainly expensive. I can get 100Wh for $28.9999

[Fred Bloggs]

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]

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.