How to measure how much solar we need?

path1 wrote:

I'm starting to read some of the links people have posted and starting to believe solar is like tire posts. What works for some doesn't mean it will work for you.

Maybe my question should of been, how much solar do you have and do you like it?

No. Links by Pianotuna to system sizing/estimates and general solar info are not lifestyle-specific. Your initial question was right, but there is no answer when there is no input data.

You asked about winter in your area. 1000W flat solar in Seattle in December will collect on the average 28 AH a day. I don't know how much the system will collect on (very typical) rainy day there when it rains all day long. Possibly 5 or 6 AH, just enough to compensate parasitic currents like LP/Co detectors and battery self-discharge. Nothing else, no loads at all. On a good day in December it will make probably 60-70, but in this area in December there can be one good day per 7 bad days, and it's not a good idea letting batteries slide towards 50% for 6 days (even if your bank is so huge that you can stretch it for 6 days).

In other words, with energy needs that you described - btw, they look like modest to me - I agree with BFL, which is something that I don't do very often :). There is almost zero sense in getting solar for coastal WA winter. Your will be able to live without generator on dry days only, AND if you max up the solar watts. On cloudy and half-wet days you could live off 1000W solar only you minimize your energy consumption as much as possible, because you will only get ~30 AH and this is only enough for lights, some heat, and very little TV time. No microwave, no hair drier, no any 110V devices.

In summer it's better, I would say you could live off 1000W there. For going South in winter, you won't have problems living on 700-800W.

How much watts people have and like it? 500W allows me living generator-free in winter in Mexico or in summer in areas like yours, though my energy needs are less than yours. Smkettner is making it on 700W in Ca, also generator-free, and I think he likes it. There is only one item that you can't have on solar under the best weather conditions - air conditioner. Pianotuna is planning to have this too, but here is "cheating" ;), charging battery while driving his motorhome and not running A/C in the night.

My numbers for Wa winter are based on flat panel. Tracking or tilting big 700W or 100W array is a royal pain. People do this with portable setup, but this is a different creature and pain of a different kind.