Ideas for alerting on voltage difference between parallel batteries?

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tk-421 asked Oct 26, '22

Ideas for alerting on voltage difference between parallel batteries?

I have a setup with two 12V batteries. They are normally paralleled, but each has its own breaker and battery fuse. They are LiFePO4 with internal BMS.

What I am looking to do is monitor the terminal voltage of both, and generate an alert if there's a significant difference. That could happen if there is significant current flow and either battery's breaker has tripped, fuse has blown, or BMS has disconnected it.

It seems the midpoint voltage monitoring of things like the BMV-712 is almost what I want, except that it expects the midpoint voltage to be 6V for a 12V system. It doesn't appear that there's any way to configure it to expect two 12V voltages instead of 6 and 12.

Is there any product in the Victron ecosystem that does what I'm looking for?

BMV Battery Monitor battery monitoring

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Answer 1 · 2022-10-26T19:45:47Z

hardy-tuner answered · Oct 26, 2022 at 07:45 PM

U can use bmv712 as well, configure starter battery and u can see both

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Answer 2 · 2022-10-27T06:40:11Z

kevgermany answered · Oct 27, 2022 at 06:40 AM

If the internal BMS is tripping the breaker inside the battery, then you need to get the values/status from the BMS. With the battery outputs connected in parallel, you'll see the same voltage on each set of terminals, less a very small difference for the cable resistance. This may be undetectable.

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