View Full Version : is my math right ?
July 29th, 2008, 16:38 PDT
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.
July 29th, 2008, 17:01 PDT
Pretty much correct... You can get pretty accurate numbers by plugging in your data to this link (http://rredc.nrel.gov/solar/codes_algs/PVWATTS/version1/).
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...
July 29th, 2008, 18:28 PDT
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.
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