Determining Amps put into the battery based on the History side of the Connect App

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Bill asked Jan 17, '19

Determining Amps put into the battery based on the History side of the Connect App

My controller shows I made 2.15 KW yesterday. I am trying to determine the approx Amps it would have put back into the battery.

I used a Calc program and if I calc it at 80v I get 27 amps and if I use 12v its 179 amps. We had reasonable sun yesterday in the desert of Arizona. Since the voltage from the panels varies all day long depending on clouds and angle of the sun I am wondering what voltage to use to calculate the approx amperage put back from the KW reported by the 100/50 controller.

Thanks, Bill .

VictronConnect amps kwh

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Answer 1 · 2019-01-18T05:24:48Z

JohnC answered · Jan 18, 2019 at 05:24 AM

Hi Bill. Presumably you mean Amp.hours, not just A. To compare with the batt rating? You did say "approx", and that's the best you'll do.

12V would be fair enough to use, so yeh, 179Ah. Charging speed will reduce that (Peukert factor), which can be quite substantial, but let's say 10%. And 'round-trip-efficiency' can be surprisingly low too. This all assuming no loads on the batts.

Then your C100 batt rating is much higher than that which can be attained with a daily-cycler, so if C10 or even C5 ratings are available with your batts, use them to compare.

SOC is one of those things too that need 'tuning', so a gospel figure it isn't.

But I can see why you're concerned. You appear to have taken more from your batts than your charging system can deliver. Perhaps an easy way to check Pb batts is before dawn, no loads. Below 12.2V I consider critical, and know I've gotta change my ways. Pushing to (say) 11.5V regularly isn't recommended, and your batts can be expected to fail early.

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Answer 2 · 2019-01-18T05:34:28Z

Bill answered · Jan 18, 2019 at 05:34 AM

Thanks, I calculated the batteries received about 78AH of charge from the controller and the other 80+ amps generated were consumed by the Inverter which I see using about 8 Amps constantly in the coach. It appears I need to add a couple more panels to deal with the constant 8 am draw during the daytime so I have a chance of recharging the overnight draw. I really would like to run the generator an hour a day or less.

Thanks!! -Bill

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