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Dominic asked

MPPT 75/15 stopped supplying load to equipment from battery, only from PV

Solar setup has been running for 6 months with no issues. Single solar panel with a new 120Ah battery, Victron MPPT 75/15 and a BMV 700. I did previously have a Pi on there running venusOS but not at the moment, will be replaced when I get there to fix current issue.

Suddenly the MPPT has stopped supplying power to the load when it gets dark. All the equipment powers off when it gets dark and back on when the sun comes up.

The battery is showing decent voltage and nothing has been changed in the setup.

The behavior seems to indicate that power is not being drawn from the battery by the MPPT and supplied to the equipment on the load outputs.

I have an identical spare MPPT which I'm going to swap out to see if that fixes it, however this is a very remote site which is hard for me to get to. Before I go there has anyone got any ideas what the problem could be?

This started 3 days ago, the only other thing I can think of is the weather has been very cold, probably colder than this setup has experienced before, could that be anything to do with it?

MPPT ControllersBMV Battery Monitor
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3 Answers
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klim8skeptic answered ·

I would think you have a blown fuse, or bad connection between the mppt and battery.

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Dominic answered ·

I didn't think of a fuse, that's a possibility. Has the MPPT got a built in fuse?

Edit: from doco it looks like it has a 20A fuse, not sure how load flows through that, the MPPT still appears to be charging the battery based on what the onsite guy is telling me. Although maybe it's actually running charge down, the load is very low.

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Dominic answered ·

It was the positive wire, which has a fise inline, not sure if it's the cable or the fuse, I suspect the fuse but it seemed to be ok. Either way we replaced the cable and the fuse, now working.

We relocated all the gear into a new cabinet at the same time and everything is up and happy.

Appreciate your input @klim8skeptic it helped direct our efforts.

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