Its been a couple of days since I have installed a victron mppt 100/20 to my caravan solar system. I have a 150W flexible solar panel and a 120AH SLD Lead acid battery. Mppt early morning is on bulk state with only 1 to 2w and when it reaches 12,7v and sun rise up high turns to state off all day even when battery drops. I’ve checked with my multimeter and output volts from solar cables are 19,5v and ah 0,9 = 17watts. Mppt app shows less volts and no watts and mppt stays in off state under full sun.
I checked the cable connections, I disconnected everything to reset victron but still I get the same results. No bulk, no battery charging and lower solar volts on app. I am so confused and I dont know if my solar is the problem or the mppt.
Any advise would be much appreciated.
Hello @Lily
Welcome.
The panel voltage has to be 5v above battery to start charge.
This video explains well.
The little part on your one screenshot has the question “why is the charger off?” If you tap that it probably says insufficient pv power.
Yes I have checked that but solar on multimeter outputs 19volts but mppt shows lower volts and no watts output. Right now volts are less than 5v from battery and mppt is on bulk mode but with no watts and battery is not charging.
Am I missing something?
Voltage under load can be different to VOC.
Are you sure polarity is correct? That can be the other reason to see voltage but no amps.
But is your multimeter accurate, have you been able to cross check it against anything else.
Yes polarity is correct on all cables, mppt is new, my battery is new, only my solar panel is 2 years old. Here in Greece we had extreme hot weather the last month. Is it possible my solar panel to have gone bad? I can’t seem to think anything else as to why I have volts but no current from solar.
Heat lowers panel voltage. That is what the temperature co efficient calculation is for. (Opposite is true - colder temperatures the panel voltage is higher).
Basically you need more solar (higher voltage) to get it working.
It turned out my solar panel was faulty and stopped producing energy. I got a new solar panel and everything works fine. Thank you for your answers.
I’ve had a similar problem with my Solar Panels, 2 x 115W. One day working fine the next day zero going into the controller. Checked the obvious cables, fuse etc. I tested the voltage from the panels and it was 20 volts so no problem there as the batteries are 12 volts. There is no problem with the controller as I connected a portable panel to it and that works fine. Surely both panels haven’t failed at exactly the same time, so any ideas anyone please?
If there is a poor connection with high resistance measuring the open circuit voltage will show full voltage. You need to measure voltage under load or short circuit current to check this. There is info such as youtube videos on measuring short circuit current with your multimeter.