Calculating AH usage Based on SOC

You don't get a super precise number, but it seems to me it's sufficient for many uses. Certainly it should be sufficient for such jobs as figuring various battery bank capacities, figuring solar installation sizing, and determining how often to run a generator to recharge.

Yes, your method would work. It would not be real accurate, unless you can accurately measure SOC. That is a problem, as the meter needs to be accurate, and the batteries need to be at rest for several hours. It would be quite hard to do this while the trailer is being used.
I suppose you could also pop the covers on the batteries and do a hydrometer measurement.
For the reasons stated above, most people use a shunt and battery meter of some type.

your 230 ah is based on a constant 11.5 a load for 20 hrs.
Used intermittently and at lower load yields a higher capacity.
SoC based on voltage is not that accurate either.

Your simple calc works for me to determine your ave usage in that type weather.
round it up by some factor!

pianotuna wrote:
Gjac,

Look up peukert law.

If you want long battery life 50% is as deep as you want to go, so it is time to recharge.

The gas valve on the fridge may use more than 16 amp-hours per day. Mine uses about 29 amp-hours per day.

Don, wouldn't my simple calculation include the peukert effect? Am I missing something basic with this simple calculation?

Gjac,

Look up peukert law.

If you want long battery life 50% is as deep as you want to go, so it is time to recharge.

The gas valve on the fridge may use more than 16 amp-hours per day. Mine uses about 29 amp-hours per day.