Mixing Batteries on Float-- Mex Test Update 2

Words I dreaded

"I DID turn on the light"

"Honey, where's the flashlight?"

"The heater quit. You're the genius. YOU get up and find out what's wrong"

Thanks Mex. I have recharged and put everything back to Float as between camping trips. I am happy I have a good batteries going into next year based on your tests, and on the way they have been working recently while camping. I'll have to find something else to fret over. :)

I believe starting the test immediately after conducting a "Top Charge" will offer a dependable base for comparisons. Putting a one to two ampere charge across the terminals and waiting until the voltage reaches 15.00 then terminating, is the way I used to prepare a flooded battery for a capacity test.

The reason for confounding information between acid density and electrical performance is that plates that shed or warp their active material have little effect on acid density and less than expected derogatory effect on square wave resistance testing. A 20 hr capacity test is most relevant, along with a SG dip, then load testing with a carbon pile.

It would be interesting for several readers to conduct a 200 amperes for 15 seconds load test on a pair of their GC-220 golf car batteries then post the results on the forum. With this baseline, it would be difficult to get fooled whether a battery is good or not. Memory fades here, but I remember something about 9.9 volts.

I think Mex meant to do a load test using the AH it took to raise the voltage from x to y, but you would need the battery to be somewhere below full to do that! :)

.18 amp hours to max out the surface charge to 14.40V. Will be a learning experience to hear what Mex has to say about that, and what it tells us about condition/state of the battery.

I'd think you'd want to put a known load on the battery and run it for time until it drops the voltage to 12.16V or whatever is 50% times the known draw item in amps, to test total residual capacity of an older battery.

pianotuna wrote:
Hi mena,

By inference 1.8 amps x 6 minutes. That's 0.18 amp-hours.

Oh, duh. LOL!

Hi mena,

By inference 1.8 amps x 6 minutes. That's 0.18 amp-hours.

How many amp hours going from v12.58 to v14.40?

Looks like we have completed this part of the test:

They seem to have stopped dropping in voltage so quickly.
was 12.72/12.66, then 12.66/12.61, then 12.63/12.59, now 12.62/12.58

Next is the recharge test from 12.6 to 14.4. I will try that on one of them first to see how long it takes, and if any tricks to it using a Vector charger set at 2 amps (does constant 2.2a according to its read-out and it goes to 14.6v). Then I'll know how to do the other one

EDIT--I think Mex left out what starting SOC to use! I was wondering if they would hit 14.4 right off since they are already 'full'

"The one amp (2 or 3 amps is acceptable) recharge kWh test is easy to do. Stop charging when voltage stabilizes at 14.4 then see how many kWh have accumulated."

So I clamped on the charger to Battery B and the voltmeter and watched the time. Charger ran at 1.8 amps steady the whole time.

It took 6 minutes and five seconds to get from 12.58 to 14.40

I let it run and voltage got to 14.62 in another minute and a few secs, then the charger stopped, said FUL

NinerBikes wrote:

And the nice thing about running things on solar during the day is that the voltage is higher, so it draws less amps during the day, leaving more amps to go into the battery for recharging purposes. Seems like a win win to me.

X2