Grounding battery and inverter

DolanRNDolanRN Registered Users Posts: 1
edited January 2019 in Solar Beginners Corner #1
Hey y'all, I have a school bus conversion that is setup for solar with 4x 120watt panels going to a charge controller then to a pair of 12v @ 125 Ah batteries in parallel all connected to a 1500watt pure sine wave inverter. I've had this system since July and, honestly, never considered grounding until a few weeks ago (I know, not good). I have since disconnected the system to keep the batteries inside for the Winter and in thinking about redoing my setup, figured I should do it properly. The inverter instructions suggest grounding to chassis but I was wondering if I can connect the inverter ground and battery ground (which is connected to one of the negative terminals, correct?) to a grounding bus bar and then attach that to the chassis with a 6awg wire. Sorry if that's confusing. If you need clarification please let me know! 


  • BB.BB. Super Moderators, Administrators Posts: 30,052 admin
    Yes, grounding the negative battery bus, somewhere to chassis (has to be frame/solid metal ground, not just a piece of sheet metal).

    Also note that sometimes the sheet metal of the vehicle is poorly bonded to the frame of the vehicle (rubber anti-vibration mounts, rust, etc.). So, sometimes you may have to bond the body to the chassis anyway.

    You did not ask, but your 1,500 Watt AC inverter is on the "large side" for a 250 AH battery bank @ 12 volts... Roughly a maximum (250 W per 100 AH @ 12 volts * 250 AH battery bank=) ~625 Watt maximum is a "more balanced" fit (the 1,500 Watt inverter can draw >168 Amps)... That is a lot from a 250 AH battery bank (and 2x that for heavy motor starting surges).

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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