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jeffp asked

Battery charge disagreement between shunt and smart controller

I'm adding panels and a smart controller to an RV that already has a lithium battery and a smart shunt.

So far I haven't been able to get the battery to receive charge. The controller shows incoming voltage at ~22v and no current on the solar side, ~14.2 volts and no current on the solar side, and that system is in absorption mode.

The smart shunt shows the battery at 13.2v.

I've checked the current to the solar controller with a multimeter and (at the time) it showed ~8A at ~22v.

Questions:

-why would the system show being in absorption mode, but no current on either the solar or battery side?

-why aren't the battery charge values in agreement between the shunt and the controller?

SOC
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jeffp avatar image jeffp commented ·
I should've added, I've connected the solar controller battery negative to the system side of the shunt, and the solar controller battery positive to the load side of the breaker connected the battery's positive terminal.
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pwfarnell answered ·

You most likely have a poor connection between your controller and the battery. Get you multimeter out and check for poor connections, every crimp, terminal and switch.

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