Wiring schematic for battery charger

czyhorse
czyhorse Solar Expert Posts: 42 ✭✭
in PV Installers Forum - NEC, Wiring, Installation #1
Hi all,

I wanted to run this by you all to see if I've got my wiring diagram right for hooking my battery charger up with the rest of my system. Please view the attached schematic and let me know if this is the correct way to hook up my Iota charger. I have the Midnite Solar MNDC box which will house most of my wiring.

schematicf.jpg

Thanks.
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Comments

  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #2
    Re: Wiring schematic for battery charger

    looks ok in general as long as the connection points can accommodate that number of connections.
    i am not familiar with your panel and i am curious as to why there is a cb going to the ground with a resistor as well? i assume it's ganged with the cb next to it, but i always thought it to be a no no to do that on a ground.
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #3
    Re: Wiring schematic for battery charger

    I believe that that 5amp breaker is the "ground fault" detector... It is ganged with the 63 amp breaker as a master panel disconnect. The resistor is probably there to provide static discharge when the ground breaker trips.

    It is so crazy to put a CB in the safety ground path for anything--Somebody does not understand how NEC / NRTL fire/personal safety design really works. They tried to add ground fault detection from 120 VAC branch circuits (5 mA) to prevent electrocution hazards and turned it on its head to provide a 5 amp ground fault trip out of "off the shelf" hardware to prevent fires--a 5 amp breaker sure ain't going to save anyone from electrocution... (AC ground fault detection is easy--DC ground fault is not--at least not off the shelf--but AC GFI was not off-the-shelf either... :roll::confused:).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #4
    Re: Wiring schematic for battery charger

    There will be a battery positive bus bar in the Epanel the Iota can terminate there after going threw an appropriate sized dc breaker. the negative would also terminate on the negative bus bar attached to the shunt.

    The GFI breaker is shown in the diagram and is required by NEC you can thank everyone's favorite friend for that John Wiles. The Midnite Epanel does not ship standard with it it is an option as certain charge controllers have it built in. While I agree it is a bunch of BS and could even be more dangerous it is the code.
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  • czyhorse
    czyhorse Solar Expert Posts: 42 ✭✭
    #5
    Re: Wiring schematic for battery charger

    Thanks for the responses, guys. The main schematic comes directly off the Midnite Solar website. I was planning on leaving the 63A and 5A breakers out of the system. I could see no reason for using them.

    Sounds like you don't see much of a use for them either, Bill...

    schematic2.jpg
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,637 admin
    #6
    Re: Wiring schematic for battery charger

    Hmmm... May be I am wrong here--Two guys with ID's that have "Crazy/Czy" in their names agree with me. :p;)

    -Bill :D
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #7
    Re: Wiring schematic for battery charger

    you know wiles is starting to scare me. first he makes everybody run the ground into the house inviting lightning and then he puts a breaker on it. trying to think of a 5 letter word for stupid?
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  • czyhorse
    czyhorse Solar Expert Posts: 42 ✭✭
    #8
    Re: Wiring schematic for battery charger

    That leads me to another question...My conductor leading from the solar panels to the charge controller in the garage will be running through my attic. I am using EMT conduit throughout the attic as according to NEC. Should my equipment ground from my panels 1) travel through the conduit and attach to my system grounding bus, 2) run outside of the conduit and bypass grounding bus and attach directly to grounding rod, 3) or bypass the attic and run outside and attach directly to grounding rod?

    I guess there is also option 4) do not bother with grounding the panels.

    Since I'm doing my own installation and live out in the middle of nowhere, I don't technically have to build this to NEC code, but I'm trying to follow it as much as makes practical sense.
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  • halfcrazy
    halfcrazy Solar Expert Posts: 720 ✭✭✭
    #9
    Re: Wiring schematic for battery charger

    I vote for 3 as long as it isn't tied to the negative leads anywhere.
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  • dwh
    dwh Solar Expert Posts: 1,341 ✭✭✭
    #10
    Re: Wiring schematic for battery charger
    halfcrazy wrote: »
    I vote for 3 as long as it isn't tied to the negative leads anywhere.

    Agreed.
    (18 character fill-in nonsense jabber.)
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  • czyhorse
    czyhorse Solar Expert Posts: 42 ✭✭
    #11
    Re: Wiring schematic for battery charger

    I have another wiring question...Following the instructions from the Midnite Solar MNDC box, I see that they show two positive conductors attached to one pole of the main inverter breaker. How many connections can you make like this before you should use a positive buss bar?

    I have the battery cable, charge controller cable, and battery charger cable that will need to share a common connection. Is it okay to use lugs and put them all on one pole of the main inverter breaker as shown in the picture below? Please advise.

    24355257.jpg
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #12
    Re: Wiring schematic for battery charger

    i'm thinking no more than 2 like you have it. to be sure, maybe you should contact the company.
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