Morningstar MPPT 45 showing false high voltage when connected to solar panels

Jaro
Jaro Registered Users Posts: 2 ✭
in Solar Beginners Corner #1
Hello,

It looks like my Morningstar MPPT 45, after almost 100,00 hours continued work, finally said enough. It may be related to the latest low temperatures (up to minus 6 C)  and my new lithium battery BMS cutting power to the electric system, still probably the solar panels tried pumping some watts via this poor controller? It was set up to stop charging the battery at 14.4 V and during UK's Winter it never charges it fully anyway (320Ah LiFePO4).
MsView shows correct battery voltage when is disconnected from the solar panels, but immediately after reconnecting, it shows much higher (and fluctuating) voltages both at the battery (13-59V) and solar (60 – 119V) inputs. Physical measurements by voltmeter showed correct voltages (60V at panels ->2x200W in series, and 13.4 at battery->during charging via generator).

Would you recommend anything else that could be done to save this great, but expensive, piece of hardware?

All the best,

Jo


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  • littleharbor2
    littleharbor2 Solar Expert Posts: 2,113 ✭✭✭✭✭
    #2
    Have you disconnected the PV and battery, then start by connecting only the battery? Is the battery voltage showing at the controllers terminals? 
     If controllers first see open circuit voltage from the panels they can be confused as to the system voltage.

    2.1 Kw Suntech 175 mono, Classic 200, Trace SW 4024 ( 15 years old  but brand new out of sealed factory box Jan. 2015), Bogart Tri-metric,  460 Ah. 24 volt LiFePo4 battery bank. Plenty of Baja Sea of Cortez sunshine.

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