Battery Bank Fuse

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  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    #32
    Re: Battery Bank Fuse

    I knew there had to be some logical explanation for the discrepancy, even if it is not the most satisfying one.
    Cariboocoot wrote: »
    So to my way of thinking this runs a bit backwards: you're stuck with a 175 Amp breaker, so make sure you use the big wire even though smaller would handle the inverter's demands. As I said before, the circuit protection has to be the weakest link in the chain. Although it still appears that the inverter would be.

    I agree. The Midnite ePanels are great - but IMO another short coming in their circuit protection is that there is no fuse or breaker between battery and the positive busbar inside the ePanel which means when working inside you need to disconnect at the battery terminal or be very, very careful. For both these reasons, I plan on putting one of those Blue Sea battery terminal fuse holders at my battery bank.
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  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    #33
    Re: Battery Bank Fuse

    that's why i opted for a breaker in my battery box to protect the wires going up into the epanel from a short and not just the wires in the epanel. i am using a 175a breaker whereas the inverter has a 125a breaker. this is what we've preached time and time again to have a fuse/breaker at the batteries because of the huge currents that could arrise from shorts. will it protect the wires? maybe and maybe not as we do oversize our wires, but it could stop damage to your batteries.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #34
    Re: Battery Bank Fuse
    mtdoc wrote: »
    but IMO another short coming in their circuit protection is that there is no fuse or breaker between battery and the positive busbar inside the ePanel which means when working inside you need to disconnect at the battery terminal or be very, very careful.

    My very first post on this forum was asking advice about how to put in a battery disconnect for my ePanel:
    vtMaps wrote:
    I need to work in my crowded E-panel in order to perform the upgrades, and I don't want to work around the extensive positive battery bus when it is hot. The only way to deactivate the bus is to disconnect the battery cables...

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #35
    Re: Battery Bank Fuse

    A couple of disconnect options that might be suitable for certain installs:
    Bussmann marine-rated circuit breakers: http://www.solar-electric.com/mr60ampdccib.html
    Blue Sea battery switch: http://www.solar-electric.com/blseabaswon3.html
    NOTE: even though it says "48 VDC" on these I wouldn't use either on a 48 Volt system because actual Voltage could be as high as 62. This is one of the down-sides of 48 Volt systems. This is another area where available equipment does not have a wide selection range.

    Caveat: it's been a long, hard day so this post may not make any sense.
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  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    #36
    Re: Battery Bank Fuse
    Cariboocoot wrote: »
    NOTE: even though it says "48 VDC" on these I wouldn't use either on a 48 Volt system because actual Voltage could be as high as 62. This is one of the down-sides of 48 Volt systems. This is another area where available equipment does not have a wide selection range.

    Since I have a 48 Volt system this has been exactly my problem. I've gone with a Blue Sea terminal fuse as shown earlier in this thread. They're rated to 58V ... so close enough I hope. No easy way to use a breaker or switch short of buying one of the larger Midnite breakers and mounting it in it's own box.
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  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    #37
    Re: Battery Bank Fuse
    vtmaps wrote: »
    My very first post on this forum was asking advice about how to put in a battery disconnect for my ePanel:

    --vtMaps

    vtMaps - did you end up putting in a disconnect? If so what type?

    I was just looking at my ePanel and was thinking about sending the battery output at the 175 amp breaker post to a Midnite panel mount breaker before it goes to the buss bar. At least with that I could de-energize the very exposed buss bar even if there would still be 2 hot terminals in the ePanel (breaker posts).

    I'd be limited to 100 amps on the panel mount breaker but this circuit would only have my charging sources on it, not the inverter.
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  • vtmaps
    vtmaps Solar Expert Posts: 3,741 ✭✭✭✭
    #38
    Re: Battery Bank Fuse
    mtdoc wrote: »
    vtMaps - did you end up putting in a disconnect?

    No, not yet.

    On the two occasions where I've opened up my ePanel I have just disconnected a battery cable. My research at the time indicated that the Blue Sea battery switch would NOT meet code in this application. When I do get around to putting in a disconnect I will have to break into the conduit (between the battery box and the ePanel) and insert a box & breaker. I didn't plan for that originally and did not leave myself much room to do that. It occurred to me at the time that maybe I could attach the disconnect box to the front of the (plywood) battery box, but I was never able to figure out if that met code. I don't have any inspectors to deal with, but I have tried to do everything by code.

    It hadn't occurred to me to put the disconnect in the ePanel itself, but I don't think there is room in my ePanel. I have a couple of 10 amp DC breakers (for my DC fridge and freezer) and a 15 amp AC breaker with an outlet in the ePanel, so I don't think there's room to put a battery bus disconnect in the my ePanel.

    --vtMaps
    4 X 235watt Samsung, Midnite ePanel, Outback VFX3524 FM60 & mate, 4 Interstate L16, trimetric, Honda eu2000i
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