MT50 Chaos

matthewmaday
matthewmaday Registered Users Posts: 1 ✭
in Solar Beginners Corner #1
I’m having difficulty deciphering the readings I am getting from the MT50. Specifically, and surprisingly, the battery icon. Does the icon really accurately reflect how much charge is left in the battery? It fluctuates a lot and seems questionable. I took a picture today (it is cloudy) and it appears to be almost depleted. It sometimes is almost depleted during during after a day of full sun and not depleted after a full night of usage. i have almost 2kwh of battery with a load of a few cellphones and two 6 watt lights. Logically, this makes no sense. I could be missing something. I just need confirmation to troubleshoot.

Thanks for all of your help
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  • wellbuilt
    wellbuilt Solar Expert Posts: 763 ✭✭✭✭
    #2
    Mine never really work % of charge was not Accurate
    Out back  flex power one  with out back 3648 inverter fm80 charge controler  flex net  mate 16 gc215 battery’s 4425 Watts solar .
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  • mcgivor
    mcgivor Solar Expert Posts: 3,854 ✭✭✭✭✭✭
    edited March 2020 #3
    Welcome to the forum @matthewmaday

    The display is merely an indication during charging, not a true representation of battery state of charge, hence it may display a full battery in direct sunlight but drops a few bars when some clouds pass by. The better method to calculate capacity is by using a shunt based battery monitoring system which calculates what is taken out of the battery versus what is returned.

    The MT 50 uses voltage which is, in itself,  is very misleading, ~14.4V will indicate a full battery icon, as soon as the sun cannot provide any more energy the voltage will drop to its fully charged rest voltage, somewhere in the 12.7V regon thus indicating perhaps 3/4 on the display, this is normal for a less sophisticated type display. 

    This is merely an explanation of what you are perhaps seeing, your actual circumstances will depend on details such as array size location, loads an so forth.
    1500W, 6× Schutten 250W Poly panels , Schneider MPPT 60 150 CC, Schneider SW 2524 inverter, 400Ah LFP 24V nominal battery with Battery Bodyguard BMS 
    Second system 1890W  3 × 300W No name brand poly, 3×330 Sunsolar Poly panels, Morningstar TS 60 PWM controller, no name 2000W inverter 400Ah LFP 24V nominal battery with Daly BMS, used for water pumping and day time air conditioning.  
    5Kw Yanmar clone single cylinder air cooled diesel generator for rare emergency charging and welding.
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