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ianalex avatar image
ianalex asked

MPPT 75/15 no volts at Load, Yellow LED not on

I can't figure out what is wrong with our BlueSolar MPPT 75/15 charge controller. Ideas appreciated. Situation: The yellow LED charge indicator light isn't coming on at all, even though there is sun on the PV panels and the PV open circuit V is 19.45 V. When the PV panels are connected to the PV terminals on the controller, V across the PV terminals is 10.74 V, while V across the battery terminals (with the battery connected) is 10.87 V. The fuse is ok, and the green power light remains on. All wiring is correct polarity. The only load is low-power LED lights, 12V DC, totalling about 25W. The controller is about 4 years old. Load voltage is zero, but I think that's because the low voltage load disconnect jumper is set at 11.1 V.

MPPT Controllers
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2 Answers
dazey77 avatar image
dazey77 answered ·

Solar voltage/power too low. Your panels are in full sun? Could be faulty panel. Is it a Bluesolar with no bluetooth? My guess would be a panel issue. The controller appears to be doing what it should, taking the panel voltages down to try and get power but if there is no power behind the panels it will fail. Not sure we can rule out the MPPT either at this stage.

The fact that it has been working for 4 years, something must have failed. Whats the panel setup?

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jonasb avatar image
jonasb answered ·

I have the exact same problem. Did you find the cause of the problem?
any tips for me?

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