[Ruko]

This is the way I understand it but I am by no means an expert. So someone please correct me if I am wrong.

It is all about the amp hours. A typical 27 series 12 volt deep cycle battery is 90 amps. When you connect them in paralllel the voltage stays the same and you add up the amperage. So 3 of them connected in parallel would be 12 volts and 270 amps.

Most 6 volt batteries are between 180 and 225 amps. When connected in series the amperage stays the same but you add up the voltage. So 2, 6 volts hooked up in series will become 12 volts but the amperage stays the same. So 2, 6 volt batteries with 225 amps would be 12 volts at 225 amps.

That means 3, 27 series, 12 volt batteries at 90 amps each would have more amps than 2, 6 volt batteries at 225 amps each.

This is in perfect conditions which we pretty much never have but at least it will give you an idea. Then you need to find out the amp draw on the appliances you want to run. This will determine how long the batteries will power said appliances.

If you start with 270 amps and have a 2.7 amp draw you will be good for 100 hours. If you have a 27 amp draw you will only last 10 hours. If you have a 50 amp draw your batteries will only last about 5 hours.

Then look at the output of the solar panels you install. If the appliances draw less than the solar output you will be good, at least while the sun is shining. If they draw more than the solar panels can produce you will drain the batteries. Of course solar output is dependent on sunshine. So it will vary from day to day, angle, shade from trees, cloud cover etc. Then if you plan on watching your tv in the evening after the sun goes down you will be relying completely on the batteries.