Warm Midnight Solar DC breakers

NorthGuy
NorthGuy Solar Expert Posts: 1,913 ✭✭
in Off Grid Solar & Battery Systems #1
I have noticed that my MidNight Solar 63A DC breakers are getting warm on touch under load (30-50A). I cannot tell which ones because they're mounted as a block, and it all gets warm. Is this a normal occurence with these breakers?
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  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    #2
    Re: Warm Midnight Solar DC breakers

    It's pretty much that way with most Breakers and fuses. They are restricting the current flow and react to it by either opening or melting and breaking the circuit. I was just feeling a 250 amp fuse that had 160 amps flowing through it, I was like, dang that's hot, I'd hate to feel 250 amps.
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  • Vic
    Vic Solar Expert Posts: 3,208 ✭✭✭✭
    #3
    Re: Warm Midnight Solar DC breakers

    N G,

    It would not hurt to re-torque the screws of each terminal of each breaker.

    There is some normal voltage drop, even in Magnetic-Hydraulic CBs -- the coil is some of it, plus the normal drops at each connection etc.

    Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH X2@48V, 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #4
    Re: Warm Midnight Solar DC breakers

    I would definitely re-torque! I always go back and do this about one hour later, I've been known to re-torque a week later it's the conservative electrician in me. Everytime I add battery water I also do this. I have had blade fused disconnects that we're new and slightly oxidized and got WARMER than I liked I scotch brighted the blade applied anti ox and the problem went away. Warm under those Amps is ok/normal , HOT is not! Be safe..........
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  • waynefromnscanada
    waynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    #5
    Re: Warm Midnight Solar DC breakers
    Blackcherry04 wrote: »
    It's pretty much that way with most Breakers and fuses. They are restricting the current flow and react to it by either opening or melting and breaking the circuit. I was just feeling a 250 amp fuse that had 160 amps flowing through it, I was like, dang that's hot, I'd hate to feel 250 amps.

    My finding over the decades as well, but was surprised at how warn, almost hot the bolted 100 amp fuse got on the output of my MX-60 when handling 50 or 60 amps, and yes, connections were clean and tight. Have since replaced it with a double 40 amp Square D QO breaker and under full load it just only gets the chill off it. Happy with it. Rated 48 VDC but is only handling up to 15.5 volts max.
    One place I worked had a whole panel of 15 and 20 amp breakers, all continuously pushed to near their max, and that whole panel would get warm, not just the breakers.
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  • H2SO4_guy
    H2SO4_guy Solar Expert Posts: 213 ✭✭✭
    #6
    Re: Warm Midnight Solar DC breakers

    My Midnite breakers run warm to hot. It may help with a block of them to act like a heat sink, but it may also keep the heat in and not allow air to circulate around them. They do seem to keep working however.

    skip
    12K asst panels charging through Midnite Classic 150's, powering Exeltechs and Outback VFX-3648 inverter at 12 and 48 volts.  2080 AH @ 48 VDC of Panasonic Stationary batteries (2 strings of 1040 AH each) purchased for slightly over scrap, installed August 2013.  Outback PSX-240X for 220 volt duties.  No genny usage since 2014. 
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  • silvertop
    silvertop Solar Expert Posts: 155 ✭✭✭✭✭
    #7
    Re: Warm Midnight Solar DC breakers

    I do like Midnight Solars products I'm picking up a outdoor din rail fuse combiner box for the new ground mount array, and a big baby disconnect box for my power wall. I am still going XW MPPT-150 because I cat5-e interconnect my controllers (just ordered today). I do wish Midnight controllers could be tied this way without additional hardware........There products are solid A+++
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  • zoneblue
    zoneblue Solar Expert Posts: 1,220 ✭✭✭✭
    #8
    Re: Warm Midnight Solar DC breakers

    Re classic, you can connect multiple controllers using the new followme functionality.
    1.8kWp CSUN, 10kWh AGM, Midnite Classic 150, Outback VFX3024E,
    http://zoneblue.org/cms/page.php?view=off-grid-solar


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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #9
    Re: Warm Midnight Solar DC breakers

    Thank you everyone for the input.

    Looks like I don't need to worry about that. Although I will need to tighten the screws just to make sure. Thank you Vic.
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  • DanS26
    DanS26 Solar Expert Posts: 269 ✭✭✭
    #10
    Re: Warm Midnight Solar DC breakers

    I've had good luck with silver conductive grease.

    http://www.amazon.com/Chemtronics-CW7100-SILVER-CONDUCTIVE-SYRINGE/dp/B00447S32W/ref=sr_1_2?s=industrial&ie=UTF8&qid=1378936958&sr=1-2&keywords=silver+conductive+grease
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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  • NorthGuy
    NorthGuy Solar Expert Posts: 1,913 ✭✭
    #11
    Re: Warm Midnight Solar DC breakers
    DanS26 wrote: »
    I've had good luck with silver conductive grease.

    Have you used with wire-to-breaker connections?
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  • DanS26
    DanS26 Solar Expert Posts: 269 ✭✭✭
    #12
    Re: Warm Midnight Solar DC breakers
    NorthGuy wrote: »
    Have you used with wire-to-breaker connections?

    I've used it only on the blade connections, but mfg recommends for all connections.
    23.16kW Kyocera panels; 2 Fronius 7.5kW inverters; Nyle hot water; Steffes ETS; Great Lakes RO; Generac 10kW w/ATS, TED Pro System monitoring
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