question

toonpuissant avatar image
toonpuissant asked

MPPT 100/50 suddenly stops charging

Context:

- on a boat, in sunny circumstances

- 4x 170Wp solar panel array (2x2 in series then parallel)

- 400Ah LifePO4 battery (70% state of charge)

- 1 100/50 MPPT

Without any warning, the Victron MPPT 100/50 between the solar panels and battery stops charging. The app is showing 0W and only 13V on the solar side. When I measure the disconnected solar cables, I get +/-50V; when I measure after I connect them to MPPT, I get 13V.

Tried the following without any success:

- use the bluetooth app to disable and enable the charger

- disconnect all MPPT cables and re-connected in the right order

- I have carefully checked and re-done all the wiring


I looked in the previous topics, but could not find any immediate answer. My guess is the unit must be faulty, right? Any suggestions for other things I could try to remedy this would be very welcome.


Thanks!

MPPT SmartSolar
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1 Answer
pwfarnell avatar image
pwfarnell answered ·

The data suggests that you have a poor connection in your cabling between the MPPT inducing a high resistance and voltage drop so the MPPT tries to draw power but the poor connection restricts the flow of electricity and all you see on the MPPT input terminals is battery voltage. Check all your MC4 connectors, all wiring terminations and any fuses, switches or breakers. What is very common is people using cheap circuit breakers of the type shown on the PV to MPPT and these are well known for poor connections. If you have this type of breaker use one from high quality manufacturers such as Blue Sea and make sure it is from them not a clone.

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