Did you check the weight on that monster battery? Can you lift a 130 pound battery?
The advantage of using golf cart 6 volt batteris is you get the capacity of a 8D battery in two easy to lift 67 pound peices.
You will have about equal votlage drop from a 250 amp battery system regardless of it being in a single 12 volt battey, or a pair of 125 AH 12 volt batteries, or a pair of 250 AH 6 volt batteries in series making the 12 volts. There is no real advantage of one over the other.
My first set of golf cart lead acid Trojan T-105 batteries lasted about 13 years, I took them out when I started full timing and gave them to a friend, they still worked. The replacements lasted only 6.5 years, I was not nearly as dilligent in keeping the water level high enough, and that did them in to a early grave. Prior batteries for me where 12 volt deep cycle, and average life on those was about 2-3 years. So I do like the golf cart batteries.
AGM should also perform well. They will not last 13 years, but should exceed the 6 years I got from my not so well maintained lead acid batteries. Remember to keep them charged, and not go below about 35% state of charge. It is much better to recharge every day for an hour than to let them discharge a lot, and abuse them.
Even better is recharging via a 300 - 600 watt solar system. You can get away with a smaller battery system, in part because your daytime needs will be met by the solar system.
Because of your electric refrigerator using up to 600 watts per night, I would suggest a larger system, like all the space on your roof can handle. The panels are fairly cheap these days, only about $1 per rated watt.
SunElec.comYou can ask a whole page of questions just about a solar system, and get lots of advice. I made my own mounts. Would recommend only 100 - 200 watt panels, larger ones do not fit well on the roof, smaller ones make to many holes in the roof. I would recommend wiring 2 like panels in series, providing the battery charge controller can take the voltage, and then wire pairs of panels in parrelle to the controller. That way shading on one panel will not effect the other pair of panels amperage output, and wiring size will be as small as practical.
If you have a controller like the Solar Boost 50, it can take in a nominal 24 volt input (up to about 45 volts input from the panels) and charge a 12 or 24 volt battery bank. It adjusts automatically to the higher input voltage. Some panels have a 30 or 38 volt output(open circuit) so they are not wired in series like a pair of 12 volt nominal panels would be.
The SB 50 can put out 50 amps at 12 volts, or about a 600 - 750 rated watts system. If there is more input, the system will "Clip" the output to a maximum of 50 amps, at say 14 volts (700 watts). That should be more than enough to run the refrigerator without drawing down the battey during the day. And when the refrigerator is off, the battery should charge enough to make it through the next night.
Good luck!
Fred.
PS: I hope that you already know that high toque motors like a refrigerator require pure sine wave power, not the lower cost modified sine wave power. It might start fine with no load on MSW, but once it is cold, and the pressure is different between the cold side and hot side, starting current might increase a lot.
