HELP! New to Solar and moving soon!

Standard AC induction motor compressor 120 VAC refrigerators have very high starting current (over 1,000 VA is not uncommon). And if self defrosting, may draw 200-500 Watts for a period of time.

In general, a 1,200 to 1,500 Watt AC inverter is recommended for running a standard energy star refrigerator... That works out to a minimum (for flooded cell deep cycle batteries) of ~480 AH @ 12 volt or 240 AH @ 48 volt (basically, 4x 6 volt @ 220 AH golf cart batteries minimum). Note that 6 volt golf cart batteries are generally a very good starting battery (cheap, pretty rugged, flooded cell can use a hydrometer to monitor charging)--And there is a good chance you will murder your first bank or two--So golf cart batteries are a good starter set.

If you are drawing 1 kWH per day from the battery bank, 2 days of storage and 50% discharge would be:

• 1,000 WH * 1/0.85 inverter eff * 1/12 volts * 2 days storage * 0.50 max discharge = 392 AH @ 12 volts (or 196 AH @ 24 volts)

So--Your battery size is based on the surge of 4x golf cart batteries.

For full time off grid--It is really good to have 10% minimum rate of charge (5% to 13% typical solar range--5% for weekend/summer use, 10%+ for full time off grid):

• 440 AH * 14.5 volts charging * 1/0.77 panel+controller deratings * 0.10 rate of charge = 829 Watt array minimum (based on battery bank capacity)

And then based on hours of sun per day... You did not say if you will be using a genset for bad weather:
http://www.solarelectricityhandbook.com/solar-irradiance.html

Atlanta Georgia
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 56° angle from vertical:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
3.55	3.96	4.86	5.24	5.36	5.00
Jul	Aug	Sep	Oct	Nov	Dec
5.18	5.01	4.82	4.92	3.96	3.52

So, (guessing) Atlanta--Little genset use with 3.52 hours of sun (December average):

• 1,000 Watt*hours per day * 1/0.52 off grid system eff * 1/3.52 hours of sun per day (Dec) = 546 Watt array "break even" December
  

So--somewhere between 546 Watt to 829 Watt array (or larger)...

Note--If you can get a DC refrigerator (not propane or tri-power ammonia type)--Your surge current drops way down and you can use a 1/2 size battery bank (2 golf cart batteries) and a smaller solar array (and save the AC inverter).

Small house--No computer, cell phone, clothes washer, pressure and/or well pump, etc.? 120 VAC refrigerator typically are what drive folks from small (500-1,000 WH per day) to medium size solar power systems (nominal 3.3 kWH per day for a very efficient off grid home is a good aim point).

Power usage is a highly personal set of choices. And for a cost effective off grid solar power system, choosing very power efficient appliances (and minimizing energy usage) is usually key.

-Bill