Batteries are down to 23% and Conext MPPT 60 150 Controller is faulting Out


I had a turnkey solar system with a battery backup installed that is certainly NOT turnkey..  I am a NOVICE and do not understand most abbreviations, so I need plain English help.  I have 8 Trojan LC16 Re-B 6V batteries wired in series.  The system keeps faulting out saying DC Over-voltage shutdown.  The trigger is set for 26V.  Should the configuration for this system be higher?  I am pretty sure the system in configured wrong, but I do not know how to set it correctly.  I called tech support at Schneider, but they won't talk to residential owners on the weekend.  Will someone please help me?  Thanks!


  • Raj174Raj174 Solar Expert Posts: 795 ✭✭✭✭
    Hello Dianne,
    Have you tried reseting the charge controller? You can do so by shutting off the PV in breaker then the charge controller breaker to the battery. Then switch the charge controller breaker back on. If the charge controller comes up ok, then switch the PV in breaker back on. It may be that the PV in voltage is too high.

    4480W PV, MNE175DR-TR, MN Classic 150, Outback Radian GS4048A, Mate3, 51.2V 360AH nominal LiFePO4, Kohler Pro 5.2E genset.
  • BB.BB. Super Moderators, Administrators Posts: 32,596 admin
    Can you tell us a bit more about your system?

    What model/brand of solar charge controller... Are you charging with another source (backup genset, AC mains, AC to DC battery charger, wind turbine, etc.)?

    Also, do you have a volt meter of some sort--Have you measured the bank voltage?

    What is the solar array (brand/model of solar panels, how are they are they wired--I.e., 2 in series * 3 parallel strings, etc.)?

    26 volts does not sound like a reasonable over voltage alarm for any typical battery bank (>~16 volts for a 12 volt bank, over >~32 volts for a 24 volt bank, etc.). Is this a battery bank or a solar array over voltage alarm?

    In general, time is on your side until you get your system under controller--EXCEPT for the battery bank. Batteries that are taken near dead, not properly recharged, or over charged can easily be damaged or ruined.

    If this was a turnkey install--Is there an issue with your installer not coming out to debug/repair?


    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Dave AngeliniDave Angelini Solar Expert Posts: 6,129 ✭✭✭✭✭
    This does not sound or the OP did not make it sound critical. It should be dealt with as the guys here have said.
    Call the installer and tell them you need help.
    In general most people with battery back-up need to know what they are talking about as there needs to be a level of expertise with batteries, if not just the safety aspect.

    The default on an mppt-60 from schneider for over voltage shut down on a 24V bank is over 30vdc. This function is handled by the inverter/ charger however. It sounds like you are grid-tied and should shut off the circuit breaker to the battery charger in case you are over charging. That does not make sense as you stated the batteries are at 23%. Just shut everything off that you can find and make the call to you installer. This is for the safety of not just your battery but your home!!

    Be safe out there!
    "we go where power lines don't" Sierra Mountains near Mariposa/Yosemite CA
    E-mail [email protected]

  • EstragonEstragon Registered Users Posts: 4,496 ✭✭✭✭✭
    Maybe I'm missing something, but 8xL16 6v in series = 48v nominal bank. Sounds like the rest of the system is set for 24v nominal?

    I agree that shutting off all the breakers and getting the "turnkey" installer to fix it is a good plan.
    Main daytime system ~4kw panels into 2xMNClassic150 370ah 48v bank 2xOutback 3548 inverter 120v + 240v autotransformer
    Night system ~1kw panels into 1xMNClassic150 700ah 12v bank morningstar 300w inverter
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