Quick Battery Drain

For all issues involving the Smart Alternator Regulators, V1, V2 and V3

Quick Battery Drain

Postby HansR on Sun Jul 04, 2010 10:34 pm

My problem is this: the house battery voltage on a battery bank of 780Ah drops from full overnight to about 12.25 - 12.35 V having run up less than 100 Ahs. This seems an extraordinary drop for such a large bank. Is this correct or is it an unjustified concern? And what to do?

I have 6 new Trojan 145 6V batteries connected in series and parallel to make 3 12V sets. These constitute the house battery bank.
I have checked all batteries and they stay fully charged overnight without a significant drop in voltage.
I recorded the following for 4 of the 6 batteries (2 disconnected to check any voltage drop)

05:15 12.88 V -10.9 A 17.1 Ahs switched off the battery charger
05:45 12.40 V -10.9 A 22.6 Ahs
06:20 12.39 V -10.8 A 28.8 Ahs
07:20 12.41 V -6.1 A 39.4 Ahs one fridge cuts out
08:15 12.35 V -8.3 A 46.8 Ahs
09:15 12.35 V -5.3 A 54.3 Ahs some effect from the sun

Is this series of records sufficient to make comments?
I also did some records with all batteries connected and using a linear voltage drop (which of course doesn't happen) would indicate a battery bank of no more than some 140 Ahs in stead of 780 Ahs.
Note, the one change I made is that I installed a small computer fan to exhaust the battery compartment, now that I have flooded batteries, where I draw the power from TB1-2 (ON/OFF) on the SAR which only has power when the engine runs. Could this have an effect?
So, what is happening here? Can you help.
One final comment: the Emon shows the batteries as 7/8 full with 55Ahs. Shouldn't this be 97Ahs?
Cheers
HansR
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Re: Quick Battery Drain

Postby Coulomb on Mon Jul 05, 2010 3:38 pm

7/8 full of 780 Ah leaves you with 682 Ah remaining. Those fractional displays are granular, by necessity, but meant to give a quick look like a fuel gauge in an auto.

Your battery voltage drop seems excessive for the light load on them. Have you read this article?
http://www.amplepower.com/primer/testbat/index.html
Coulomb
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