Solar help please (1 Viewer)

[Lenny HB]

I've done a battery test today on the two 80a/hr leisure batteries.
I ran a 4-5 amp load for nine hours, start voltage was 13.4 and end voltage 12.4 although I wasn't able to let them rest for long after removing the load.
Do they sound healthy ?
TIA

Did you run the test on them separately?

 

[Figaro]

No together in situ.
Hoping not to have to remove them

 

[Lenny HB]

Sounds a bit on the low side I would expect 12.6, the voltage will gradually rise over 30-60 min when off load.

You need to test them individually one may be pulling the other one down.

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[Lenny HB]

State of Charge Gel battery voltage
100% 12.85+
75% 12.65
50% 12.35
25% 12.00
0% 11.80

 

[autorouter]

I ran a 4-5 amp load for nine hours, start voltage was 13.4 and end voltage 12.4

12.4 volts is about 55% charged, ie 45% discharged.

4-5 amps? I'll work out both 4 and 5 amps

4 amps for 9 hours is 36 amp-hours. This represents 45% of the actual battery capacity.
Actual capacity of battery is 36/45 x 100 = 80Ah

5 amps for 9 hours is 45 amp-hours. This represents 45% of the actual battery capacity.
Actual capacity of battery is 45/45 x 100 = 100Ah

So your batteries which were originally 2 x 80 = 160Ah have deteriorated so that their capacity is 80 or 100 Ah.

Manufacturers say their batteries are at end of life if they have deteriorated to 80% of their original capacity. 80% of 160Ah is 128Ah. Since your batteries are between 50% and 62.5% or their original capacity, I'd say they are due for replacement.

The only caution is, are you sure the batteries were really 100% charged at the start of the test? I'd charge them for 24 hours on EHU, then re-run the test, just to be sure. Be sure to let the batteries rest for at least 30 min before taking the voltage reading. Also make sure the solar panels are not confusing matters by disconnecting/covering them.

 

[Figaro]

Thanks for your helpful information.
I'd turned all 16 lights on, mostly led's, couple of halogen. Hymer gauge needle was showing 5amp discharge, maybe slightly less.
I thought they'd held up pretty well but maybe not having seen your calculations.
I'll run again test and allow a rest rest period at the end which I couldn't do this weekend.
Thanks again
Chris

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