High voltage input warning

jneale519jneale519 Registered Users Posts: 2
I have an off grid solar system in a school bus conversion. I keep getting a high voltage warning and my solar will stop charging my batteries. I have 4, 315 watt solar panels in series coming into a 100 amp mppt solar charge controller, 6 180ah agm batteries wired in parallel and a 3000 watt pure sine inverter. I run a small refrigerator off the 110 a few outlets and everything else is 12v. 

Comments

  • mike95490mike95490 Solar Expert Posts: 9,101 ✭✭✭✭✭
    Just guessing and tossing out things to consider

    Is the voltage warning on the PV side or the Battery side ? 

    Have the days been unusually cool or sunny ?

    i see no need to have 4 panels in series, to charge 12V battery.  The voltage of 4 in series could approach the input limit of your controller, triggering a shutdown.  Wired 2S2P would still allow the MPPT to function efficiently, and with less conversion loss from high DC voltage to 12V.  with 2 in parallel, you would have more amps in the PV loop, but is it enough to matter - depends on the gauge of the existing wire and the distance from panels to charge controller.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • PhotowhitPhotowhit Solar Expert Posts: 5,427 ✭✭✭✭✭
    jneale519 said:
    I keep getting a high voltage warning and my solar will stop charging my batteries. I have 4, 315 watt solar panels in series coming into a 100 amp mppt solar charge controller, 
    So what are the spec's on your charge controller?


    Not a lot of 100 amp charge controllers out there. Could be an off brand, but I'd post a few and their spec's;

    Aims; Max PV open circuit voltage: 155Vdc
    https://www.amazon.com/Aims-Power-SCC100AMPPT-Charge-Controller/dp/B078VL7HGX

    EPever; Max. PV open circuit voltage: 150V
    https://www.amazon.com/EPEVER-Charge-Controller-Flooded-Tracer10415AN/dp/B07JVQY8QB

    Renogy RVR100;
    Magnum;
    Maximum PV input voltage (any condition)
    200 VDC + battery voltage or 240 VDC - whichever is lower

    Here are some 315 watt solar panels with math for basic VOC voltage in a string of 4 panels (the VOC will be higher when very cold)

    Canadian solar VOC=Voltage (VOC)40.1V 410.1V x 4 =  160.4V

    LONGi VOC= 37.9 volts x4= 151.6 volts

    These are modern 120 cell panels

    Previous they would normally be 72 cell panels Like;

    REC 315PE72 VOC=45.5 x 4 = 182 volts

    SW315 Mono - SolarWorld VOC= 45.6 x 4 = 182.4 volts

    Trina-Solar TSM-315 voc=45.6...

    The voltage of strings of 4 are usually too high for standard MPPT charge controller, The Magnum can handle most of these, but the others aren't realistic.

    I'd suggest switching your configuration to 2 pairs of 2 panels. You can do this on the top of your bus with "Y" connectors, Like these;

    MC4 Parallel Connectors Y Style Male-Female Branch Set SLCBL-46

    ...and still use the same wires bringing the power into the bus. Check the ampacity of the wire! and your breaker/fuse size.

    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • jneale519jneale519 Registered Users Posts: 2
    Thanks I have the Epever 100a mppt  and I'm using 2gauge wire from  solar charge controller. 
  • PhotowhitPhotowhit Solar Expert Posts: 5,427 ✭✭✭✭✭
    jneale519 said:
    Thanks I have the Epever 100a mppt  and I'm using 2gauge wire from  solar charge controller. 
    So 4 - 315 watt solar panels don't have a VOC above the 150 volt limit?

    What panels do you have?
    Home system 4000 watt (Evergreen) array standing, with 2 Midnite Classic Lites,  Midnite E-panel, Prosine 1800 and Exeltech 1100, 660 ah 24v ForkLift battery. Off grid for @16 of last 17 years. Assorted other systems, and to many panels in the closet to not do more...lol
  • SafariParkEarthSafariParkEarth Registered Users Posts: 3
    Good info here - you can't go above the max input voltage for your controller/inverter.
    Crystal Cold CC18SS, Blizzard BF-18F, Premier P4800W PV BR Solar Controller, Trojan Batteries, Sunstar ST-16RF, Sunstar ST-21F
  • littleharbor2littleharbor2 Solar Expert Posts: 1,572 ✭✭✭✭
    Good info here - you can't go above the max input voltage for your controller/inverter.
    Unless you have Midnite Classic charge controllers with Hyper VOC feature, You can add your nominal battery voltage to the Max VOC rating. A Classic 200 in a 48 volt system can tolerate 248 volts max VOC. That being said, a properly designed PV system should never need to get anywhere near the max VOC.

    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, 700 ah @24 volt AGM battery bank. Plenty of Baja Sea of Cortez sunshine.

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