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tomhaines29 asked

New solar panels won’t activate

I am replacing six flexible 100-watt solar panels on my motorhome with three rigid 175-watt Renogy panels. I also have two 100amh lithium batteries. When I connect a panel to the rooftop combiner box my MPPT 50/100 solar charger shows Off. Everything worked fine with the old panels. So far I have connected only one panel to the box. When it didn’t work I unplugged the first panel and I tried connecting a second one, thinking maybe the first panel was at fault , but same result. I have put a load on the batteries, thinking maybe if they were topped off the controller wouldn’t call for a charge. But the batteries are showing 13.2 volts now. They're usually 14.2 or so when plugged in. img-7073.png

MPPT SmartSolar
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2 Answers
elvis avatar image
elvis answered ·

The MPPT see's no Voltage. Check the input and output of the combiner box with a multimeter. Then if still no voltage check each panel at the output cables with a multimeter. I suspect the panels are wired together incorrectly. Also, Dont exceed the input voltage rating of the MPPT. Its very likely the panal voltage is quite different then the old ones. Are the panels all in series? Paralell?

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pwfarnell answered ·

Are you using MC4 plugs to connect the panels to the combiner box. If so make sure that the plugs on the new panels have the same polarity as the ones on the old panels. Are there any breakers or fuses in the circuit that could have tripped. Have you checked the settings page to make sure the MPPT itself has not been turned off.

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