Your converter recharges the batteries via the shore power cord, right?
So what is extracted from the batteries is replaced by the converter.
If an adapter is used to allow the shore power cord to be plugged into the Kill-A-Watt meter then the meter can be plugged into a 15-amp wall socket.
Flip off ALL the AC breakers in the rig except for the dedicated AC breaker to the converter.
NOTHING AC should be switched on including wall sockets, refrigerator, water heater, etc. The refrigerator must be working, set to gas.
Two or three days @ 24/hrs day should accumulate "X" number of kWh on the meter.
It is important to live in the rig like you normally do and not go bulimic all of a sudden. Lights, television, fans, porch light. Everything used like it was SUMMER vacation. Some thought should be given to the amount of time that is normal for dining room, kitchen lights and fan, bathroom including fan, and bedroom lights including Fantastic roof fan. Don't Scrimp or your reading will not be worth ten cents.
Shut off all the loads. Shut down the converter after -exactly- 48 hours
Read the kWh accumulated on the Kill-A-Watt meter. Write it down
Calculator time...
Divide total kWh accumulated then divide by 12.5
This will give you approximate amp hours energy used for the 48 hours
Divide the amp hour figure by a factor of 2
This is a nominal average of ampere hours used daily.
Your battery bank must not be less than TWICE the number of amp hours accumulated for 24 hours. Actually 2.5X minimum would be safer
Your solar requirement will be roughly 5-Times or 500% of your daily amp hour accumulation.
This estimate needs more caveats that the RV.Net server can hold. But it is a better-than-nothing guesstimate that beats the tar out of spreadsheet pure guesswork.
If you plan on using an inverter, get it now and add it's hunger from start to finish with the Kill-A-Watt.
Be prepared to add panels and batteries when reality arrives.
