[TriLUG] recommendations for UPS 12V batteries?

[Joseph Mack NA3T via TriLUG]

On Sat, 18 Apr 2020, Pete Soper via TriLUG wrote:

> +1 for PowersonicFirst question: did the ten year battery come out of an 
> identical UPS?

no. I should have mentioned this. (mea culpa)

The batteries that lasted 10 years came out of a large UPS with 8 batteries.

The batteries that last 2 years come out of the standard small APC UPSs with 1 
or 2 batteries. I have about a dozen of these UPSs and the batteries all last 
only 2 years. I can get 2 years out of a battery in a car, that gets bounced 
around and suffers high temperatures. The UPSs here only have to handle the 
occassional power bump. I would hope that the UPS batteries would do very much 
better than the car batteries. At least Shay is getting 5 years out of his.

> My experience has been that poorly designed UPS electronics can be worse than 
> the battery selection.  Years ago I instrumented a couple UPS devices to see 
> how the behaved. I recall one that was in the wrong county with respect to 
> float voltage.

I see. Maybe all my APCs are like that.

> Too low and the electrodes accumulate sulphate and die. Too high and the water 
> is disassociated and driven past the pressure release as gas, leaving the 
> electrolyte short of ions. And the float voltage needs to be temperature 
> compensated.

yes. Understand the problems here. However I never bothered to find out the 
temperature dependence.

> It would be a pure hobby play, but making a crummy UPS optimal with some added 
> smarts might be an antidote for cabin fever.

I'm plenty busy already (comes from being retired)

> You could start by just seeing what voltage the batteries are maintained at.

but you're right. I should measure the voltages anyhow.

> Everything you need to now is on a web site called "battery university"

I have his book (recommended)

Thanks Joe

--
Joseph Mack NA3T EME(B,D), FM05lw North Carolina
jmack (at) wm7d (dot) net - azimuthal equidistant 
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