DC Disconnect Switch for Battery Bank with 2/0 wire.

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KJ7YM
KJ7YM Solar Expert Posts: 30 ✭✭
in Off Grid Solar & Battery Systems #1
I am seeking advice for a reasonably priced 24 volt DC disconnect switch for my battery farm/inverter.
Like so many things as soon as something gets an exotic label, like Aquaponic, or Solar, or HVAC, etc., etc, some of the simplest devices suddenly cost hundreds of dollars.

I wish to put a simple disconnect switch on my battery bank that can handle 2/0 wire.I am beginning to think I will need to build my own, because even as an Air Conditioning guy in a gioeld that is just full of customer abuse and unethical over charging, I find the Solar Industry to be surprisingly proud of every re-branded or Chinese made item that caries a tag saying solar.

I am hoping that someone else may have already gone down this road before me and found a generic manufacturer or at least a semi-reasonable solution to this dirt simple switch. I am a master industrial engine mechanic, generator repair tech, HVAC tech, and went to college for a industrial electrical degree. So I guess if I have to I can cobble something together on my own. But what I am asking is do I really have to. I obviously m willing to pay, even sometimes somewhat unreasonable amounts to have someone else do the work for me. But there is just something about this bone simple switch that is going too far in my opinion. Thanks for letting me rant guys. Maybe I am just being overly sensitive today. But really? Really? :-)

Larry
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Comments

  • KJ7YM
    KJ7YM Solar Expert Posts: 30 ✭✭
    #2
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    I did find this which looks somewhat promising: store.mwands.com/wire-terminals-connectors/dc-disconnect-switch-for-battery-banks-and-power-sources/
    Am I allowed to post links to vendors? If not please let me know and I will delete it. I am just trying to show the product as an example. I do not even know who this store is.

    Larry
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #3
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    Relevant links to hardware from other vendors is fine. No problem at all.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • KJ7YM
    KJ7YM Solar Expert Posts: 30 ✭✭
    #4
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    Ah! Better yet this looks promising If I am going to have to modify something to work. It is rated at 7200 watts, is a double pole which gives me a much more warm and fuzzy feeling when it comes to isolating a Batter Bank in an emergency. I wish I could see inside of this thing to get a better view of what is up. I will have to check and see if my inverter needs to pull more that 300 amps at surge :-)


    http://www.zoro.com/i/G1231133/?utm_...2CkaAlSD8P8HAQ
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  • Anawa
    Anawa Solar Expert Posts: 225 ✭✭✭
    #5
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    Here is a product you may want to consider. There are various designs that could fit your configuration, but not sure about your pocket book. Yeh, this "Green Thing" is all about the Green(bucks).

    Blue Sea: https://www.bluesea.com/products/6006/m-Series_Mini_On-Off_Battery_Switch_with__Knob_-_Red

    Paul
    Paul 
    in Georgia

    System 1: PV- 410w Evergreen, Mppt- Blue Sky Solar Boost, Batt - 225ah Deka AGM, 12v led house lighting,
    System 2: PV- 215w Kyocera, PWM - Morningstar PS30, Batt- 225ah Deka GC's, 12v led house lighting, Dankoff 12v water pump,
    System 3: PV- 1.5kw Kyocera, Grundfos 11 SQF well pump, 3000 gal above ground water storage, dom water & irrigation,
    System 4: PV- 6.1kw Kyocera, Mppt- Outback FM80-2ea, Inverter- Outback FX3648-2ea, Batt- 804ah GB traction, Grundfos BMQE booster pump 240v, Mitsibushi mini-splits 240v, 18k and 15k
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #6
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    Why not a Midnight box and a pair of DC breakers. Midnight carrys switch duty rated breakers.

    i've heard of issues with contact tension and high resistance on Marine disconnects running high amps for high hours.
    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 ,

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  • cupcake
    cupcake Solar Expert Posts: 254 ✭✭✭
    #7
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    This is what you want:

    31AbxERl7oL.jpg


    Midnight Solar MNDC250...

    One box for ALL of your DC shutoffs.

    The big 250amp breaker is included and shuts off your battery-bank/inverter
    Then there is a 5 spot DIN-rail to mount shutoff breakers for your panels and charge controller, and then another spot for your GFID breakers


    That's all you need...


    -cake


    ~1.5Kw PV in parallel
    Morningstar MPPT-60 controllers (2) in parallel
    3 Trojan tr-1275's in parallel 450ah total
    Samlex 2,000 watt 12-volt inverter hardwired


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  • solarix
    solarix Solar Expert Posts: 713 ✭✭
    #8
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    Ditto on the big 250A breaker, but seriously - that's only if you need permitting and inspections. This is just 24Vdc, technically below the 50V code threshold and therefore exempt. For many years, before solar got civilized, everyone just wired the batts directly so no question about voltage drop in the disconnect. Need to disconnect the battery? just unbolt the wire at the inverter end.
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  • cupcake
    cupcake Solar Expert Posts: 254 ✭✭✭
    #9
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    What is this "50v code threshold" that you speak of? Enlighten me. Here in the Republic I've not yet heard of such a thing. Altough it is well known that the Republic has the strictest codes in the nation...

    -- cake in a cup
    ~1.5Kw PV in parallel
    Morningstar MPPT-60 controllers (2) in parallel
    3 Trojan tr-1275's in parallel 450ah total
    Samlex 2,000 watt 12-volt inverter hardwired


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  • 2twisty
    2twisty Solar Expert Posts: 199 ✭✭✭
    #10
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    A friend of mine had a used 3-phase AC breaker where the center pole's cable clamp was damaged. Its rated for 300A, and 4/0 wire. So I have both my positive and negative going through this breaker. It's huge overkill, and I've got fuses of lower value to protect the wiring, so I can use the breaker as a disconnect switch.
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  • unseenone
    unseenone Solar Expert Posts: 61 ✭
    #11
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    If you also want to physically disconnect, you could also do Anderson plugs in addition to a switch or breaker. I wanted that, so I could easily completely disconnect that battery.
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  • KJ7YM
    KJ7YM Solar Expert Posts: 30 ✭✭
    #12
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    I just read one of my earlier comments about 3 or 4 down from the top, and noticed it was full of typo's. I must have been sleepy when I typed that.

    Also I would like to thank all those that commented you guys are wonderful!

    Corrected comment:

    Ah! Better yet this looks promising If I am going to have to modify something to work. It is rated at 7200 watts, is a double pole which gives me a much more warm and fuzzy feeling when it comes to isolating a Battery Bank in an emergency. I wish I could see inside of this thing to get a better view of what is up. I will have to check and see if my inverter needs to pull more that 30 amps at surge :-)


    http://www.zoro.com/i/G1231133/?utm_...2CkaAlSD8P8HAQ
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  • KJ7YM
    KJ7YM Solar Expert Posts: 30 ✭✭
    #13
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    I just read one of my earlier comments about 3 or 4 down from the top, and noticed it was full of typo's. I must have been sleepy when I typed that.

    Also I would like to thank all those that commented you guys are wonderful!

    Corrected comment:

    Ah! Better yet this looks promising If I am going to have to modify something to work. It is rated at 7200 watts, is a double pole which gives me a much more warm and fuzzy feeling when it comes to isolating a Battery Bank in an emergency. I wish I could see inside of this thing to get a better view of what is up. I will have to check and see if my inverter needs to pull more that 30 amps at surge :-)


    http://www.zoro.com/i/G1231133/?utm_...2CkaAlSD8P8HAQ
    · Share on Twitter

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