Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inverter

Dolly Bee
Dolly Bee Solar Expert Posts: 30 ✭
in Solar Beginners Corner #1
Will this work ??
Say 4 solar panels 250 watt each - to Midnight classic 150 lite controller - to 4 Trojan T105 batteries wired series/parallel to Inverter that is for 12 volt ?? then on to ac panel.
No DC on that project now - but will leave ability to add DC disconnect later.
Later when I can afford the $2,000. Inverter, I can re-wire the batteries.
Meantime, if I mess up and blow it up - I won't be as upset.
Ignorance is not bliss - it's a headache causing troublemaker throwing speed bumps in the learning curve.
Dolly Bee
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    Well four 250 Watt panels is a 1000 Watt array. It ought to produce about 64 Amps peak on a 12 Volt system. The MidNite Classic will definitely handle this.

    The four Trojan T105's configured for 12 Volts would be 450 Amp hours. You really don't need 64 Amps for that, although @ 14% peak charge rate it won't hurt them either.

    You'd get more than 2kW hours AC daily from that.
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  • Dolly Bee
    Dolly Bee Solar Expert Posts: 30 ✭
    #3
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    Thank You Cariboocoot - Your help and patience is Greatly Appreciated..!!!

    I'll have to go back, try to find my notes and try to refigure what my needs might be for the business (max running 2 - machines 1/2 HP, plus some smaller tools, a rope cutter and some lights). The original estimate from me was overkill I learned & have not gone back to recalculate it. busy.

    2kW sounds like quite a bit to draw from.
    Lots of sun in mountains in New Mexico during the summer when I'll be using this set-up.

    Just noticed 1 of my electric bills that should only be a deep freeze and some lights averages about 80kW per month (until it gets hot and the air conditioner kicks in to protect leather and rubber).

    Dolly Bee
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #4
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    Kilowatt hours. Got to get the time factor in there. 80 kW hours per month is more than 2 kW hours per day. This could be a problem.

    A/C is always a problem. Big power user even when you use the efficient mini-split type.
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  • Dolly Bee
    Dolly Bee Solar Expert Posts: 30 ✭
    #5
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    Maybe it is Firefox - but my back button & reload doesn't help me one bit. Maybe I'm hitting the wrong buttons.
    I hit back arrow and reload this page.

    Anyway - sorry I did not explain myself correctly.

    No A/C on this project. too cool in mountains. (Understand A/C is HUGE draw)

    (Bill I was talking about was comparison from here. 80 hrs = compressor for deep freezer + several shop lights + light machine usage.
    I was thinking freezer compressor draws more than 2 machines 1/2 hp.
    So - I'm thinking I'll use less hours than that bill.
    What I tried to say was local bill gets higher in the summer when I have to use A/C here to keep cool the leather and rubber.
    still sounds confusing.)
    sorry.
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  • Dolly Bee
    Dolly Bee Solar Expert Posts: 30 ✭
    #6
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    Isn't $225 for 250w Sharp panel a good price ??
    Or $195 for 240w American panel ??
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,642 admin
    #7
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    With Firefox, make sure you have cookies enabled at least for this website (should take over an hour for a post to "timeout" when writing it).

    We may need to calrify how to measure your electrical usage.

    Watts is a "rate" likes Miles per Hour
    Watt*Hours is an "amount" like drove 50 miles per hour for 8 hour = 400 miles total [fix math--Thank you Vtmaps. -Bill]

    And kWatt is simply 1,000 * Watts...

    1,200 Watts = 1.2 kW
    1,200 watts * 10 hours = 12,000 Watt*Hours = 12 kWH

    Most electricity bills are monthly and change in kWH (kilo watt hours).

    So a 100 kWH bill is:

    100 kWH / 30 days = ~3.3 kWH per day = 3,300 Watt*Hours per day

    A refrigerator may take (on average) 130 watts and run ~20 minutes per hour (1/3rd of the time). Its daily energy usage would be:

    130 watts * 24 hours per day * 1/3rd duty cycle = 1,040 WH per day = 1.04 kWH per day

    A small off grid solar system may be ~1,000 WH (1kWH) per day loads... That will runs lights, laptop computer, small water pump, etc.

    A mid size off grid system may be ~3.3 kWH per day. That will run an "energy star" refrigerator with ~1-1.5 kWH per day usage plus other lights, laptop, pump, clothes washing machine, etc. (efficient appliances chosen, and not "wasting power".

    10-30-100 kWH per day ranges from a very efficient home (with natural gas for heating/cooking/etc.) to a standard north American home, to a home with Air Conditioning in a hot climate.

    Using your present electric bill and/or a Kill-a-Watt type meter (for plug-in AC appliances) will help you understand your present power usage and what scale of system would be needed to supply that amount of power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • Dolly Bee
    Dolly Bee Solar Expert Posts: 30 ✭
    #8
    Re: Will this work ? 250w panels, midnight 150, 4 batteries series/parallel to 12v inver

    Thank You Bill

    I'll try to figure out how to check on that cookie thing tonight and how to turn it on for this website.

    Thanks for your information.

    I'll try to get back to more accurately figuring my needs tonight.

    Maybe I better get those 6 panels after all - to allow for future growth.

    Maybe I can just take 4 panels with me this time. This will only power the business shop.

    The RV has a solar panel to keep those batteries charged and a "side" inverter to run a few things extra without having to run the generator.
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