extra solar panel and relay to start/stop electrical loads

blueskiesblueskies Registered Users Posts: 54 ✭✭
in General Solar Power Topics #1
ok, so my cargo trailer roof is completely covered with panels and everything is working well so far.  except my samplex 1500 w. inverter does not like my 700 WATT microwave or induction heating plate.  but that's ok.  it's for sensitive electrical stuff like a computer (a/c type sine wave).  so i'll probably have a cheaper inverter for those items and turn it on only when using the microwave or induction hot plate.  But here is what I am thinking about now - and I appreciate anyone with similar projects:  I still have a small leftover panel that could be put on the back with a leftover charge controller with an extra battery just for stuff like charging phones, etc.  But I am thinking that if it were connected to an old-fashioned 12v relay, it could control when certain loads switch on and off from my main panels.  IE the sun is shining pretty brightly and it is enough to make the old fashioned relay switch on and - bingo - non-essential loads will be switched on from the main systems only when the sun is bright, even if I'm in bed or away.  Any experience or thoughts appreciated.
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  • blueskiesblueskies Registered Users Posts: 54 ✭✭
    #2
    ps - the panel is about max 17v and max 7 amp
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  • blueskiesblueskies Registered Users Posts: 54 ✭✭
    #3
    from amazon i purchased 

    5 Pack - EPAuto 30/40 AMP Relay Harness Spdt 12V, 5-PIN SPDT Bosch Style


    i expect these will come in handy even i receive better advice

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  • mike95490mike95490 Solar Expert Posts: 9,190 ✭✭✭✭✭
    #4
    >  I still have a small leftover panel that could be put on the back with a leftover charge
    >  controller with an extra battery just for stuff like charging phones, etc.

    Just wire it to your main battery bank.  KISS applies.
    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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  • blueskiesblueskies Registered Users Posts: 54 ✭✭
    #5
    I have received good information from a few great experts here.  I believe I have achieved a great deal more than what I could have without free communication.  My time as a learner here may be overdue.  I will not keep it stupid, Simple.  Nor did any great innovator.  Goodbye.
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  • RCinFLARCinFLA Solar Expert Posts: 1,351 ✭✭✭
    #6
    I would be more inclined to think your battery cabling is too small having too much voltage drop at inverter.  You are peaking at close to 150 amps.
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  • mike95490mike95490 Solar Expert Posts: 9,190 ✭✭✭✭✭
    edited October 2020 #7
    KISS = keep it stupid simple.  no comma.    
    instead of making a complex system with sensors and relays and such, get it working simply, then as you gain experience, time and money, begin to elaborate.  Going whole hog wild from the start, seldom works as well as originally thought.  +30 years in the spacecraft industry learned me the benefit of working with someone else's money and time, to take a good product and improve it to the point where it became unworkable.

    Like chaining a wrench at the top of the dam spillway, so anyone can pull the weir boards without having to look for the tool that walked off.    Or car windows that can roll up or down, anytime, from inside, without a key
    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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