[TriLUG] reason not to mix batteries in UPS

[Joseph Mack NA3T via TriLUG]

On Sun, 8 Jan 2023, David Brain via TriLUG wrote:

> Hi,
>
> There are LiFePO4 batteries with the same form factor as SLA batteries -
> that have a battery management system built in and so im theory could be a
> drop in replacement - e.g (picking at random, there are many)
>
> https://www.amazon.com/stores/HowellEnergy/page/25E75BEA-EBC2-4EBD-BD0F-646755CECED9?ref_=ast_bln

looks interesting.

> But there's mixed reviews about using them on a UPS - some UPS don't seem
> to 'like' them and so won't charge or accept them as non faulty.

a regular Pb-acid battery is a two terminal device - you charge through 
the same port as you discharge. All the Li-ion batteries I know about are 
three terminal devices - you charge through one port and you discharge 
through another. The Howell battery is a two terminal device. The list of 
functions of their battery management system seems complete, but I don't 
know how they can do it.

A minor wrinkle is that some of the batteries arrive with 0V output and 
you have to activate them with 18V (12V is not enough). If you had a chain 
of 4 batteries in series and some started discharged and some charged, 
you'd need parallel resistors to balance the charge.

One entry in the review says that you can't put them in series.

Several of the reviews say that they don't work, or die quickly, even when 
used in a device that expects a Li-ion battery.

The specs say a lifetime of upto 10years. I've never had a cell phone 
Li-ion battery last more than 2 years and I take care not to charge it to 
death, take it down to 25% once a month (to reset the meter) and not let 
it get hot.

So even if the Howell batteries work, I'm not expecting them to last 
longer than an SLA.

Joe

> I tried one in a small UPS and so for it's been OK - but it's only been in
> use for a month or so.
>
> David.

-- 
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
Don't upgrade a working machine - it won't work any
better - it could work worse; it may not work at all.
Homepage http://www.austintek.com/ It's GNU/Linux!