Re: R 3rd party lithium battery replacements safe & OK 2 use?

Paul <[email protected]> wrote:
> On Wed, 4/2/2025 4:20 PM, Ant wrote:
> > Are those third party lithium battery replacements (e.g., 
> > https://a.co/d/bjBzSf4) safe and good to use for APC UPSes?

> "The operating current of 12V 10Ah battery is 10A,
> and the maximum instantaneous current is 30A(5 seconds)."

> That means the battery can put out 120W continuously.

> Now, work out the max power output of the APC = 650W

> You're running a 650W UPS using a 120W (continuous) battery.
> That does not sound right, somehow :-) And do you really want
> to leave four or five additional batteries sitting on your
> night table ? I think not.

> The UPS will float charge them constantly at 13.5V .
> Lithium do not float charge (officially, you're not
> supposed to do that). Proper lithium charging requires the
> charger to stop... and not start charging again, until the battery
> is discharged somewhat. The APC does not know you have connected
> LFP -- it is not a mind reader.

> LFP (LiFeP04) chemistry is specifically selected for this product,
> due to its "tolerance of abuse". NMC could not be abused
> like this. You can put current into LFP, even when it
> does not want the current. LFP has lower power density and the ability
> to be abused on its charge cycle. It also has a slightly
> higher charge cycle count than laptop batteries do (if you treat
> them right). These cells are not used in laptops or inside phones
> (not enough runtime, lower power density).

> I don't really know, how to gauge when one of these is failing.
> Sure, it might fail the once-a-day impedance test (which
> lasts for a second or two), but how beat to death would
> this particular battery chemistry be, when it triggers the
> "beep" thing ? APC UPS only beep once on an impedance failure.

> You can tell when an APC SPS (Standby Power Supply) UPS is
> failing, by the metal case temperature. An ice-cold APC SPS
> is working properly. If the APC gets lukewarm to the touch,
> that means your lead acid pack has shorted-out cells inside.
> Time to replace, when the housing gets even a bit warm.
> The SPS type does not dissipate power when in quiet mode,
> which is why it can be cold like that. When it floats the
> battery at 13.5V, hardly any current flows into a "healthy" battery.
> Maybe 5-10mA. How much current flows into the LFP pack ???
> I don't know. And my livingroom seems a poor place for
> pyrotechnical experiments.

> *******

> The price of a kilowatt hour of battery has dropped a lot over time.
> This battery is priced as if the price had never dropped. It's still
> a thousand bucks. You can put eight of these in parallel, but the advert
> says the battery is limited to 50A discharge current (instead of the
> 100A by itself). With eight of those in parallel, you get 400A continuous.
> You can put two of the batteries in series, making 24V @ 100A. But at that
> price, you won't be doing that. And because it has a pushbutton control,
> you won't be buying that (it likely means a BMS test circuit is being
> used as a power control). Batteries have cells, but they have a BMS
> (Battery Management System) circuit board on top which monitors the
> cells and may attempt to "balance" the battery during charging.

> https://batterybrands.com.au/products/pylontech-rv12100-12-8v-100ah-1280wh-4s4p-lifepo4-battery-soc-indicator-m8-terminals-max-2s-or-8p-ip20-rating

> At the price of those batteries, you don't abuse those with a float charge.
> You would use a proper Lithium charger that cuts off the charger when
> the pack is full. It would not fit into your APC, but it would be
> a bit closer to the correct capacity numbers. And it's $1000 so you
> won't be buying that anyway.

> The State of Charge (SoC) indicator on that pack, is four LEDs and a push button.
> You press the switch, and if four LEDs light up, the battery is full. Take
> your finger off the test button and the LEDs stop illumination. Some laptop
> packs used to have a SoC like that on them. Four LEDs.

> If I could find an authoritative source claiming "this was OK for X years",
> I would tell you that. So far, I haven't seen a BatteryUniversity.com app note
> on this. That's our source of non-pyrotechnical battery operation info :-)

> I believe some domestic Japanese UPS are using Lithium. I haven't checked
> lately, to see if anyone in North America has had the cheek to do that
> (fire risk). No, you can't buy the Japanese one as it is the wrong voltage.
> That helps prevent grey-market sales of such. When they are good and
> ready to make a 115V one, they'll make one.

> Since they are constantly working on new battery designs, I believe one
> day, we will be shed of the 3-year-drop-dead Lead Acid ones and we will
> get a quality design. But it's not ready quite yet. Solid state electrolyte Li
> is one possible type. Expect abusive pricing on the batteries, as the
> batteries will never match lead acid on price. People insist on selling
> $100 per kWh batteries for $1000 per kWh. "Bad monkey bad".

Thanks Paul. I was debating to get new APC Replacement Battery Cartridge 
(APCRBC124) battery replacements for my old 865 watts APC Back-UPSes: XS 
1500 (model: BX1500G) and APC Back-UPS XS 1500 (model BX1500G). One of 
them show a blinking battery icon due to its old age. :(
-- 
"Whatever you have learned or received or heard from me, or seen in me ? put it into practice. And the God of peace will be with you." --Philippians 4:9. Flow movie was beautiful with an odd ending.
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