Newby needs help with choosing batteries

[Jessejames801]

When you say 20% do you mean you only use 20% and want stop using the battery once it drops down to 80% charged ? Or you want to stop using the battery once it drops down to 20% charged ?

[Sunking]

When you say 20% do you mean you only use 20% and want stop using the battery once it drops down to 80% charged ? Or you want to stop using the battery once it drops down to 20% charged ?

Stop at 80% SOC or 20% DOD. If you plan to use 1 Kwh per day takes a 5 Kwh battery.

a 12 volt 55 AH battery has a total capacity of 660 watt hours or .66 Kwh with a daily usage 130 watt hours per day.

[Jessejames801]

I think I'm going to go with a 200 watt kit that comes with a 30amp charge controller with this set up instead of the 55 ah battery what size should I go battery should I go with ?

[SunEagle]

I think I'm going to go with a 200 watt kit that comes with a 30amp charge controller with this set up instead of the 55 ah battery what size should I go battery should I go with ?

The battery size will depend on what type (PWM or MPPT) charge controller you get.

With a PWM then the charging amps will be the total of that 200 watt system can produce. Probably around 11 amps which would match up to a 100Ah battery.

If you are using a MPPT CC that could produce almost 17amps (200w / 12volt = 16.7a) which would allow you to go with a 150Ah battery.

Sunking answered your question. 20% DOD means there is 80% SOC left in the battery. SOC = State of Charge.