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Over voltage output - 100/30 - 24v system.

This is driving me mad.

Ok guys. I purchased a Victron 100/30 smart solar MPPT and fitted it. Because of Covid I left the vehicle over winter and went back to it recently. The solar was left on to keep the batteries maintained. When I returned it was bright and sunny and my battery protect was sounding the alarm for over voltage. This has obviously going for some time. My batteries are completely fried and an inverter burnt out (Luckily it didn't catch light, I know it should have been fused!).

Basically the MPPT varies it's output according to the sun and can get well over 30v. I have measured this on my Victron battery monitor and a standard circuit tester. I have a 24v system and the app is set to that. The app shows the battery voltage between 2 and 5v (The battery monitor shows it at the normal values when not connected to the MPPT - 25-26v). The PV average input about 70v (Variable obviously)

Bottom line is I have contacted the suppliers (In USA, I am in UK - not ideal) and they suggested a few things like checking my earths etc, which I have done.

I have today moved the MPPT so it's next to the battery area and attached it into the circuit direct to the battery shunt (Neg) and Busbar (Pos). It still shows the same. I then took my batteries out, linked them in series on the ground and attached them direct to the MPPT. Same result.

Hopefully there are some pictures below of screenshots. The first picture is when the PV Isolater is off, still shows the batteries at 2.67v.

Below, the next two are when attached direct to the 24v battery. The latter two when in the vehicle circuit. It was a fairly overcast day and these values changed. They went above 32/33v to set off the battery protect. The battery protect is not between the MPPT and the batteries.solar-isolated.png


connected-to-24v-battery-v.jpg connected-to-24v-battery.pngconnected-to-system-v.jpg

connected-to-system.png

MPPT SmartSolar
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