Originally Posted by IsThatYouClaude
Makes sense. I figured the set up would get me some microwaving and maybe a touch of A/C but I missed the battery draw limit. As long as I get over that then I should be good for a weekender. Thanks for the help.
As for "a touch of A/C, here are some "perfect world numbers" to consider.
A 100 amp hour LiFePo4 battery contains between 1.2 and 1.5 Kwh of energy
A 13,500 btu A/C unit consumes about 1.5 Kw while running(not counting starting current).
An Inverter can be about 90% efficient if it's a good one. This means that 1.2 to 1.5 Kwh stored energy is effectively only 1 to 1.3 Kwh.
If all was perfect one might be able to run an A/C unit for 45 minutes per 100 ah battery. Since the max draw will be over 100 amps, two batteries in parallel will be required. First thought might be "Oh Goody, I can run A/C for 90 minutes on two batteries."
Unfortunately that's only perfect world, same current demand all the time.
Reality is that the compressor needs almost twice as much current to start as it does to run. This cuts run time drastically.
On my setup the A/C draws about the same current into the inverter as my microwave. That's a consistent 125 amps. The microwave is consuming 2 amp hours for every minute it runs (as measured by my Victron battery monitor). This is a "real world" number.
You MIGHT get an hour out of two LiFePo4 batteries if fully charged, no other power draws, and if you rub your lucky rabbit's foot.
I just run my microwave when only needed for a few minutes and run A/C on generator. If I need the A/C, I need it for hours, not minutes.