So I have a 48V battery with internal BMS. Yesterday my 480W PV (60v) was charging my battery slowly with about 3amps (until the low sun ended charging with about 1.6amps). I disconnected ONLY the PV switch (disconnecting the MPPT therefore) and this morning I turn the PV master switch on and the battery wouldn’t charge, despite there being 4amps / more sun.
I checked the battery, the MPPT PV inlet and the MPPT battery outlet and everything was normal except the MPPT battery outlet which was going totally MAD, jumping up and down in Voltage extremes - so much so it blew my 10a multimeter fuse but didn’t blow the internal 20Amp fuse despite jumping for a second to 30 amps (according to mmeter).
I bought two Victron MPPTs (75/15 and 100/20) because everyone else was, but in actual fact they are too complicated for their own good and by extension just a bad product to buy if you just want it to work rather than spend months on dense tech information and problem solving.
I also used the 75/15 to charge a small 300W battery and it couldn’t even handle that basic task for more than 5 minutes. So I took out the MPPT and let the PV connector do the work without the MPPT and it charged just fine.
If I can’t resolve the problems of these two firmware updated MPPTs; I hope I can sell them and stop regretting I bought a fad rather than an MPPT that just does the job without offering millions of variables and settings.
I just want plug and play. I think 95% of customers do.