is my math right ?

System Posts: 2,511 admin
So i am trying to make sure I am not crazy, or that I understand how this works. if I live in florida and we get 5.5 solar hours per day and I have a 1KWH array ( 5x200 watt Panels) . I would get a daily yield of between 5.5kwh and 4.27 if I factor in .77 % of loss. If I use 4.27 as my daily number then in 30 days I have 127.05kwh of output per month and if power is .13 cents per kw then you have a total savings of $16.52 per month. Is this correct or am I missing something ? :confused:

Thanks for any input.


  • BB.
    BB. Super Moderators, Administrators Posts: 33,404 admin
    Re: is my math right ?


    Pretty much correct... You can get pretty accurate numbers by plugging in your data to this link.

    To figure out your cost per kWhr, try:

    Total Cost of system + maintenance over 20+ years / # of kWhrs per year * 20+ years = $/kWhr

    Using 20 or 25 years is about as far as you would want to go out...

    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    Re: is my math right ?

    That's a good "seat of the pants guess". 5 kwh daily, to offset (I'll take a wild guess of 30KW daily useage) knocking your bill back to 25KW ! $5 a day ! But it will get better if rates go up.
    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

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