How to double the values of smartshunt? - because of wireing 2 batteries with one shunt

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mrg asked Aug 1, '21

How to double the values of smartshunt? - because of wireing 2 batteries with one shunt

i have 2 batteries. One is connected to the body at a point that I cannot change and cannot reach. The second is under the seat and there on the body.

With battery 2 I connected the SmartShunt directly to the minus pole. Both batteries are directly connected to the positive pole.

The shunt now of course shows all values halved. Can I use software, hardware (change resistance) or VRM, for example, to get the shunt to simply double the values?
Unfortunately, as I said, I can't get the wiring of the negative poles, so I can't create a common negative pole to connect the shunt.

SmartShunt battery

2 |3000

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Answer 1 · 2021-08-01T19:23:43Z

Kevin Windrem answered · Aug 01, 2021 at 07:23 PM

You could double the battery capacity to give a rough approximation of the total SOC from the two batteries.

However there is no guarantee the two batteries will charge and discharge equally due to resistance differences in the two paths from the battery to common points for positive and negative.

2 |3000

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Answer 2 · 2021-08-02T10:17:07Z

mrg answered · Aug 02, 2021 at 10:17 AM

Thanks for answer.
So the SOC may can work. But the AMPERE and WATT values are still halfed.

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2 |3000

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wkirby ♦♦ commented · Aug 02, 2021 at 11:34 AM

Given that the batteries are not the same and that the various cable lengths are different it is almost a certainty the current will not split exactly in half over the two batteries.

The resistance of the cables and the internal resistance of the batteries will be different from each other so difficult to what proportion of current will go to what branch.

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