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mcwidowmaker asked

Victron MPPT 150/70 not charging under ESS

From yesterday one of my MPPT charge controllers is not charging. It just suddenly dropped the chage rate, although the MPPT charge controller shows up on the CCGX and there are no error codes.


The system is made up of 2 x MPPT 150 / 70 charge controllers, a Multiplus 48/5000/100 inverter, a Bluenova 24kwh 52v battery bank and a CCGX. It is running ESS.


There are no error codes on the MPPT controller or on the CCGX. When looking at the MPPT controller I can see the battery voltage as well as the panel voltage and that also checks out with the multimeter. After a full day of sun, MPPT 1 records a total yield of 3W and MPPT2 records 9kw or so.


I have reset MPPT one, but it doesn't make any difference. Is there anything else I can check or should I take it in for a service?

mppt charging
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2 Answers
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seb71 answered ·

Disconnect the VE.Direct cable from that MPPT charger (maybe also reset it again after this) and see how it works in "stand-alone" mode.

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mcwidowmaker answered ·

Thanks for the help. This is just about the weardest problem I have ever encountered. Under ESS, the unit powers up and the multimeter reads the correct battery voltage at its inputs. Changing it to standalone mode, the unit refused to power up and show a voltage of 0.2v on the inputs.


Turns out the fuse on the negative line have blown, but the unit stayed on and even restarted fine with the CE direct cable connected. Once I disconnected the VE direct cable, it highlighted the problem.


What I would love to know is how does it read the correct battery voltage on the terminal of the unit with the blown fuse. Does ESS supply it information from the first unit and it generates the power from the solar, obviously with no amps as it has nowhere to go or is there another explanation?


What I have found with the sand type fuses I use is that is does allow some voltage to pass through even if it is blown, which may be enough to get the units started, but why wont it start up in standalone mode? Under ESS with the unit started the voltages on both sides of the fuse as well as on the unit was the same as on the buss bar. Needless to say, I am very confused.


Anyway, replacing the fuse fixed the problem and both units are working as they should.

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