1.2 kW PV, 832 Ah Battery Bank, 2000 W SW Inverter

With summer under full swing now, we just added to all the components of our off grid system:
- 2 more 208 amp hour 6 v golf cart batteries == 832 Ah @ 12 V
- 4 more 100 W panels == 1.2 kW arranged in 3 groups of 4 panels
- replaced 1500 W modified sine wave inverter with 2000 W pure sine wave inverter
- replaced 62 amp breaker between controller positive output and battery bank with 100 A switch
- replaced 6 AWG positive lead from controller to battery with 4 AWG

PV: 800 to 1.2kW
The system is working well. The AC power is very nice, properly grounded and can run small electronics with out any problems, hissing or issues. The system was 2 runs of 4 panels, combined on the roof in a combiner box and then put into a 16 A breaker before entering the controller. The 4 new panels are a third series and run straight to the board and into a 8 amp breaker before joining a combining bus and entering the controller. The current controller can handle just a little more at peak sun, so due to the current sale on 100 W panels, looks like I may be adding 1 more panel to each series for a total of 1.5 kW and according to MidNite, needing 1.1 classics -- just under the 1.2 recommendation of adding a second controller.

Battery Bank: 624 to 832 Ah
Added two more 6 volt golf cart batteries giving me the equivalent of four 12 V batteries in parallel. This gives us good reserve capacity and the ability to use most of our capacity during the day w/o any problems.

Inverter: 1500 modified to 2000 W pure sine wave
The output from this inverter is very nice. We've had no components complain, or fail as we did with the modified output. We will stay at 12 for now and possible add a second inverter if we need more power - mainly due to the large cost increase of purchasing a 24 V sine wave inverter. Checking the output with a standard plug checker shows that everything is properly grounded and the neutral is correct.

Still to do:
Add a transfer switch in the house so it's easier to have access to this energy.

How are we using it:
Things currently running are deep freezer, fan in green house, 2nd refrigerator/freezer, air cleaner, large DE-humidifier, radio ... with additional items as needed: including the crook pot, small oven, electric grill...

I think the max power was just over 1100 W yesterday - but it's not been clear sky all day so we're seeing about 6.1 kW for the day.

416 AH Off-Grid Battery Bank

I've been wanting to increase the storage of my small system (7x100W Panels) for a while now, but finally did so today. I've doubled the capacity to 416 amp hours.

Battery Bank
The battery bank now consists of four 6V golf cart batteries that I purchased at Costco. They are rated at 208 amp hours each. The bank is composed of two parallel banks of two batteries in series : where the two batteries in series doubles the voltage (6 to 12) and the parallel battery banks doubles the capacity (208 AH to 416 AH).

Cable Upgrade
Last night I changed out the 10 AWG wire from the controller to the battery bank with a 6 AWG wire. I was surprised to see the voltage drop at 40A with the 10 AWG over 6' of wire was 0.48 V. The 6 AWG wire will be 0.19 V now: a loss of 4% down 1.6%.

Future Upgrade
Now that winter is picking up it's stride, I don't want to loose energy when I can make simple changes. The next will be to change the 4 AWG cable from the battery bank to the inverter and replace it with 2/0. That will lower the voltage drop @ 100 Amps from 0.3 to 0.09: very significant : less than 1/3 of the loss. I should have done this earlier, but in the summer there was sunlight to spare. Not so anymore...

COST: 
208 AH 6V Battery: approximately $83 each   ==> result: storage of 416 AH
6' of 6 AWG cable: approximately $3.50  ==> result: less voltage drop from controller to battery bank

(I will upload the photo when I get data back up...)