question

paul-cotton avatar image
asked · Jun 28, 2021 8:41:06 PM

-0.02V showing on start battery

I have a starter battery, a leisure battery, a DC/DC, MPPT and PV and Multiplus. With all functioning except DC/DC since I isolate the start battery there is a -0.02V showing on the smart shunt for the starter battery. What is this indicating?

battery system voltage
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3 Answers
Mike Dorsett avatar image
Mike Dorsett answered ·

When you isolate the starter battery, are you also isolating the voltage sense wire from the smart shunt? this should go via a small fuse directly to the starter battery. A schematic of your installation would help with a question like this....

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paul-cotton avatar image
paul-cotton answered ·

Mike thank you for the reply. I am not. The sense goes from the shunt to a fuse at inlet of the battery positive the isolation is beyond this nearer the battery.

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paul-cotton avatar image
paul-cotton answered ·

screenshot-20210706-121250-samsung-notes.jpg

Isolation just removes starter battery.


screenshot-20210706-121250-samsung-notes.jpg (269.4 KiB)
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klim8skeptic avatar image klim8skeptic ·

Can we assume that the battery shown is the start battery?

And the connection to the Dc2dc charger is the input?

Isolated Dc2dc converter?


paul-cotton avatar image paul-cotton klim8skeptic ·
Correct so when isolated dc dc is off.


There is an mppt and a LiPo fully functioning in the remainder of the circuit.