Help please....

DO NOT BUY ANY HARDWARE JUST YET.

Do some simple paper designs (and costing) of the various options and the loads you want to run (as Westbranch said above).

It is very easy to purchase incompatible gear that you cannot use and just need to get rid of later--Or you make a "Frankenstien's Monster" design because you already have the stuff.

Read up on batteries--They are the heart of your system. And will, over time, be the thing that costs you the most (replace battery banks every 3-8 years of so with typical lead acid batteries) and spend a lot of time making sure they are happy.

For your loads, the fewest loads, the most efficient loads, will be your best bet. It almost always cost more to generate power than to conserve power.

Solar electric power costs (most people, roughly) around $1-$2+ per kWH for off grid power (all costs rolled in). Your electric power at your home costs about 1/10 that amount.

An average home that uses ~500 kWH per month and has a $50 to $100 per month power bill--The same thing off grid will cost around $500 to $1,000 per month, and you have to pay 5-10 years of "bills" up front (and more if you accidentally "murder" your first battery bank or two--Not uncommon).

For an off grid power system--If you can get full time off grid for 1kWH per day (just lights, small water pump, run a few electronics) for a summer cabin, or ~3.3 kWH per day (lights, refrigerator, well pump, washing machine, TV+Laptop) for full time off grid--That is something to aim for.

If you live in a region that does not have a lot of sun--Solar Electric power is even more costly (more solar panels, more genset fuel in winter)... Say Parsippany, NJ, fixed array tilted to 49 degrees from vertical:

http://www.solarelectricityhandbook.com/solar-irradiance.html

Parsippany
Average Solar Insolation figures

Measured in kWh/m2/day onto a solar panel set at a 49° from vertical angle:
(For best year-round performance)

Jan	Feb	Mar	Apr	May	Jun
3.23	3.89	4.45	4.68	4.83	4.98
Jul	Aug	Sep	Oct	Nov	Dec
4.99	4.88	4.73	4.31	3.30	2.94

Toss the bottom three months and use February as the "break even" month:

• 7 * 310 Watt panels * 0.52 off grid system eff * 3.89 hours per day ave sun Feb = 4,389.WH per day (4.4 kWH per day)

That is not bad... If you do a 10%/13% rate of charge (10% to 13% rate of charge recommended for full time living with off grid power system):

• 7 * 310 Watts * 0.77 panel+controller deratings * 1/0.10 rate of charge = 696 AH @ 24 volt battery bank
  
• 7 * 310 Watts * 0.77 panel+controller deratings * 1/0.13 rate of charge = 536 AH @ 24 volt battery bank (typo: should be 0.13, not 0.10 in equation)
  

12 volt bank not recommended (too large for "average" off grid components--Heavy cables, larger/extra charge controllers/not great for supplying >1,200-1,800 Watt loads at 12 volt AC inverter, etc.).

Please note--More than likely, if you choose a 24 volt battery bank, you will have to get panels in groups of 2 or 3 (i.e., 2, 4, 6.. or 3, 9, 12... to "match up" with a typical MPPT type solar charge controller).

AC inverter wise--using our rules of thumbs (200 AH per 1kW of AC inverter at 24 volts on flooded cell lead acid batteries), you can support a maximum (reliably) of:

• 696 AH / 200 AH per 1,000 Watt inverter = 3,480 Watt max inverter (minimum "makes sense" inverter ~ 1,740 Watt inverter)
  
• 536 AH / 200 AH per 1,000 Watt inverter = 2,680 Watt max inverter (minimum "makes sense" inverter ~ 1,340 Watt inverter)
  

Note, rules of thumbs designs are to get you close--These are not exact numbers and just guides to what makes sense for a reliable/cost effective installation.

Anyway--Lots to consider--Just some "numbers" to give you some ideas of what you are looking at based on what you have told us and some other guesstimates.

-Bill

PS: Fixed typo in equation (results are correct).