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jodel avatar image
jodel asked

MPPT 75/10 not charging

Hi, I have a 100 watt flex solar panel on my boat connected to a MPPT 75/10 . The system is less than a year old and was working fine. Now it is no longer charging. I am not sure if it is the panel or the controller. The open circuit voltage on the panel is 18.6. When I connect the panel to the controller it's voltage drops to 16.5. The battery voltage is 13.5. there is a mains charger connected also, but this has never effect things before.

VE direct shows voltage but no amps from the solar panel and battery state as off.

Any suggestions as to how I can fault find the issue?

Jodel

battery chargingSolar PanelMK3
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Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

PV voltage has to be 5V higher than battery voltage to start charging. After that it has to be 2V higher.

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jodel avatar image jodel commented ·

Thanks. I'll switch off mains charger to get battery voltage to drop.

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jodel avatar image jodel commented ·

Just wondering why it has to be 5 volts higher to start. Can this value be changed?


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Matthias Lange - DE avatar image Matthias Lange - DE ♦ jodel commented ·

No, it can't be changed. It's the way this MPPT works.

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