Charge controller stops before batteries are charged and still full sun

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WoodyM
WoodyM Registered Users, Users Awaiting Email Confirmation Posts: 1
My Flex 80 controller has done this a few times now.  During the day it will just stop sending amps to the batteries.  This happens when the batteries are not full and there is still full sun.  On the LCD status screen it will say "Charged" on the controller. After the first two times I replaced the breaker for the CC.  It stopped for a bit but just did it twice in a week.  Coincidentally, the last two times were during a heat wave. 

This is for a off grid system/back-up that is tied to a critical load panel for the house.  We've been using it to offset some electricity usage during the summer, it's been cycling daily then shut off from the house at night.

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  • Photowhit
    Photowhit Solar Expert Posts: 6,003 ✭✭✭✭✭
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    It could be internal heat causing the charge controller to shut down for safety reasons. I know the Midnite Classic is designed to reduce throughput to protect it's self if it get's too hot. Is your power center outside?

    If that's not the problem, perhaps it's the voltage drop when solar panels get hot reducing the voltage to an unusable level. Could you give us some information about your array/setup? Voltage of battery bank and the series/parallel of your panels along with their VMP or cell count.


    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Magnum MS4024, Prosine 1800(now backup) and Exeltech 1100(former backup...lol), 660 ah 24v Forklift battery(now 10 years old). Off grid for 20 years (if I include 8 months on a bicycle).
    - Assorted other systems, pieces and to many panels in the closet to not do more projects.
  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
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    How do you know you are at full charge ? 
      If I’m powering a load my cc bumps up Solar production to meet the load 
     when the load  ends the controller reads charged until I reach float voltage then it reads float .
      If I turn off my inverter at 1100 am I go to charged because there is no load , so more power 
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .