712 - SOC and Ah vs Voltage discrepancies

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jdlloyd24 asked May 23, '19

712 - SOC and Ah vs Voltage discrepancies

Recently, I’ve noticed an issue with my 712 where the SOC and Ah seem to align (not exactly, but close), but the battery voltage is much lower than where the former are. For example this morning, the voltage was 12.20v, but it showed I was at 77% and 59Ah consumed. My battery bank is 250Ah from 2 12v Lifeline group 31 AGM batteries.

As a note, I have been running the furnace overnight and shut it off when I get up, so I’m not sure if this is keeping the voltage low for a set period of time after it’s been shut off? At this point, I’m not sure what to trust, the SOC, Ah consumes, or battery voltage. Any help is greatly appreciated!

SOC

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Answer 1 · 2019-05-23T15:56:40Z

jdlloyd24 answered · May 23, 2019 at 03:56 PM

To further this, I have the generator currently hooked up and it’s charging at 13.45v which is between my powermax chargers float (13.2v) and absorption (13.6v). My point is, if the voltage of 12.20v were accurate, the batteries would be around 55%, requiring bulk voltage (14.4v). Since it’s not going that high, should we assume the SOC and Ah are accurate then?

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Answer 2 · 2019-05-27T03:49:59Z

jdlloyd24 answered · May 27, 2019 at 03:49 AM

Anyone have any ideas? It continues to show a much lower voltage compared to SOC and Ah, so I’m lost at what to follow and/or how to fix.

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Answer 3 · 2019-05-27T05:44:30Z

JohnC answered · May 27, 2019 at 05:44 AM

Hi JD. The Ah will be accurate, the SOC *may* be if it's set up right. It's a calculated figure though, and there's a few factors involved which might determine how much reliance you apply to it.

The V can only be of use when there's zero load/charge applied and been standing that way until any drift ceases - could even be several hours.

Ageing Pb's could indeed show a lower V than you'd expect, and the real world with such is mentally deflating. And eventually wallet deflating.. hopefully your's aren't there yet.

To feel better, you could set your batts to a lower capacity in the 712.

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