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busdennis asked

MPPT measuring wrong battery voltage

Dear all. My MPPT unit as stopped charging the battery's. On investigation my victron app is reporting the battery at 13.82v but the actual voltage is 12.56 at the battery terminals, the MPPT controller battery terminals and is also confirmed by my victron shunt at 12.56v

I've factory reset the MPPT with no effect, what do i do next please. Why would the app report an higher voltage and im assuming thats why im getting no charge

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2 Answers
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wkirby answered ·

You did not mention which model of MPPT you have got.
I am going to assume it is one of the models which has a fuse on the bottom near the connectors? If so, then my immediate suspicion is that the fuse is open and this is why the battery is disconnected from the MPPT.

When the battery is disconnected from the MPPT then the MPPT will go straight to its target Voltage, 13.8V seems like the float Voltage that you have set up.

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busdennis answered ·

Sorry, its the 75/15 with a 20amp fuse. The fuse has been checked and it was fine so returned to the unit. your answer does make sense has some times the app as returned a voltage of 14.4. think i may just replace the wire from the unit to the battery which is routed via a breaker and a fuse>

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wkirby avatar image wkirby ♦♦ commented ·

Sometimes 14.4V makes even more sense. This would most likely be when the MPPT target Voltage is at the Absorb stage.
Can you see the pattern? 14.4V Absorb, 13.8V Float. If it showing those Voltages independent of the battery, then it is not connected to the battery.

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