Inexpensive DC breaker for small inverter

Steve961
Steve961 Solar Expert Posts: 93 ✭✭✭✭
I am putting together a small system for a remote cabin, and will be using the Morningstar 300 watt inverter, with a 200 AH AGM battery, for lights, laptop, etc. I am wondering if there are any inexpensive DC breakers out there for small inverters such as this. I know I could go with a fuse, but I would like to have the convenience of a breaker to disconnect the inverter from the battery when I leave. Morningstar does recommend a 100 amp fuse, but that seems a bit much for a 300 (600 peak) watt inverter.

I was looking at the following from NAWS:

Square D QOU 60 amp DC circuit breaker

Midnite Solar Baby Box Enclosure for 1-4 Din Rail Breakers

Any other ideas or recommendations?

Thanks.

Steve

Comments

  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter

    The Square D QO series are rated for DC, and they are cheap, and they are reliable and they are available nearly every where.

    If it were me, ( and I have the same inverter), I would use a 50-100 amp automotive type fuse at the battery to protect the wire. I would then run that into a 30 amp breaker to feed the inverter. I have separate 12vdc and 120vac breaker panels, as some of the loads in the house are 12vdc and some are 120. That way a small QO breaker box can carry all the 120 vac branch circuits as well.

    Good luck,

    Tony
  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    Re: Inexpensive DC breaker for small inverter

    For the Morningstar unit, which has a surge rating of 600 watts for 15 minutes I would suggest a 60 amp breaker, MorningStar I believe lists 100 amp in there documentation on the SureSine
  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    Re: Inexpensive DC breaker for small inverter
    icarus wrote: »
    The Square D QO series are rated for DC, and they are cheap, and they are reliable and they are available nearly every where.

    If it were me, ( and I have the same inverter), I would use a 50-100 amp automotive type fuse at the battery to protect the wire. I would then run that into a 30 amp breaker to feed the inverter. I have separate 12vdc and 120vac breaker panels, as some of the loads in the house are 12vdc and some are 120. That way a small QO breaker box can carry all the 120 vac branch circuits as well.

    Good luck,

    Tony

    :confused:

    Tony, I don't think that's what you meant. I thought 120 VAC and 12 VDC in the same box was a no-no?
  • Steve961
    Steve961 Solar Expert Posts: 93 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter

    Tony:

    If I went with an automotive type fuse, could I go with a combination like this:

    DC blade ATM Maxi-fuse

    Inline Maxi fuse holder with crimp terminals


    Also, would it be best to have the fuse right at the battery, or 1-2 feet away in the metal box with the 30 amp breaker.

    Thanks.

    Steve
  • boB
    boB Solar Expert Posts: 1,030 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter
    :confused:

    Tony, I don't think that's what you meant. I thought 120 VAC and 12 VDC in the same box was a no-no?

    Not nessecelary. Look at the inverter boxes like MidNite, OutBack and Xantrex etc.
    They have both in one. Have for many years. Just gotta make sure they don't touch and have high enough rated insulation, etc.

    boB
  • crewzer
    crewzer Registered Users, Solar Expert Posts: 1,832 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter
    Morningstar does recommend a 100 amp fuse, but that seems a bit much for a 300 (600 peak) watt inverter.

    The external 100A fuse is a "catastrophe" fuse. The SureSine 300 has three 40A automotive type fuses inside the unit. Check page 13 of the Installation and Operation Manual.

    HTH,
    Jim / crewzer
  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter

    Not to argue with a know genius (aka BoB) Marc, you are correct, you caught me in another overworked evening! I have TWO Square D boxes, one 12vdc only and one 120 vac only!

    As for your question Steve, the link to the fuse and holder is exactly what I mean. Should be able to source locally, but NWAS is always a good source as well.

    Tony
  • Dapdan
    Dapdan Solar Expert Posts: 330 ✭✭
    Re: Inexpensive DC breaker for small inverter

    Hey Steve,

    I use these breakers/disconnects and have had no problems with it over the past year. It is very robust built to operate in very caustic environments (on a boat) and are ignition proof and accept large end terminals. You can get them from any store that caters for boats and they are usually between $30 - $50. Surface mount them and you are ready to go within minutes. They come in a range of amperages of 25 - 150amps and are rated up to 48v.

    Cheers...
    Damani


    http://bluesea.com/category/3/10/productline/overview/174

    7135-7148_182x182.jpg
  • DeltaFox
    DeltaFox Solar Expert Posts: 27
    Re: Inexpensive DC breaker for small inverter

    I found this circuit breaker that will hold 10,20,30,or 60 Amp fuses DC
    On Ebay Item # 370213540348.

    You might check your auto radio installer. They might have one But it might not be the right size of fuse but you can find it on ebay or the internet.
  • BB.
    BB. Super Moderators, Administrators Posts: 33,431 admin
    Re: Inexpensive DC breaker for small inverter

    This link to the seller's ebay listings for circuit breakers may last longer than the auction number.

    Interesting looking devices--no rating information (don't really know if it is safe for use on a home sized battery bank or not).

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • Steve961
    Steve961 Solar Expert Posts: 93 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter

    These are some great ideas guys, it looks like I have a lot more options than I thought.

    Thanks.

    Steve
  • DeltaFox
    DeltaFox Solar Expert Posts: 27
    Re: Inexpensive DC breaker for small inverter

    BB I have one of these coming and between my batterys and the inverter I have a fuse holder , I'll try to put a picture here of it and It seems to be very good.

    .FuseHolder.jpg Available in 20, 30, 40, 60 AMP - please indicate the one you need in payment.

    4/8 awg input &output

    Size: 98mm (L) x 43mm (W) x 35mm (H)

    High Current Circuit Breaker
    Stops Power Surges from Damaging Your Amps

    Mount on Panel or Firewall

    Unique Push Button Reset can also be used as a Kill Switch

    High Tech water resistant housing


    This is a photobucket where I have the one that I'm useing right now.
    I'm not connecting anything to the house. I have no plans of doing this sence I have made two solar panels now.
  • Windsun
    Windsun Solar Expert Posts: 1,164 ✭✭
    Re: Inexpensive DC breaker for small inverter

    Those look like the standard Euro type automotive 12 volt breakers, but no ratings so I am sure not UL, and no idea if they are good for 24 volts or higher.
  • Steve961
    Steve961 Solar Expert Posts: 93 ✭✭✭✭
    Re: Inexpensive DC breaker for small inverter

    I did a little searching, and found a great little fuse block from Blue Sea that takes MAXI fuses from 30 to 80 Amps. It also accepts wire sizes from 18-4 AWG. I think this is what I will be using.

    Blue Sea MAXI Fuse Block

    2ahwdog.jpg
  • JESSICA
    JESSICA Solar Expert Posts: 289 ✭✭
    Re: Inexpensive DC breaker for small inverter
    Dapdan wrote: »
    Hey Steve,

    I use these breakers/disconnects and have had no problems with it over the past year. It is very robust built to operate in very caustic environments (on a boat) and are ignition proof and accept large end terminals. You can get them from any store that caters for boats and they are usually between $30 - $50. Surface mount them and you are ready to go within minutes. They come in a range of amperages of 25 - 150amps and are rated up to 48v.

    Cheers...
    Damani


    http://bluesea.com/category/3/10/productline/overview/174

    7135-7148_182x182.jpg

    Greetings:

    At this site you can find the blue-seas type dc breakers, and some others, for a lot less money:

    https://www.surpluscenter.com/sort.asp?numrec=20&lastrec=20&sort=1&keyword=EMWB&catname=electric&UID=2009100407310287