trip report: running an Air Conditioner (2006 OEM) from batteries alone.

[rickst29]

I just returned from a Northern California trip with afternoon exterior temps in the high 80s. Having installed an 'Easystart MicroAir 364' previously, the rotor start amps were not a problem.

I was able to run the OEM Coleman 'Mach' AC unit from a pretty good inverter and my set of LFP (Lithium Iron Phosphate) batteries), but my run time in late afternoon was limited to less than 2 hours.

Due to shade from from campsite pine trees, my solar "600+ watts" was providing around 400 watts into the Inverter at the start of the run, but maybe as little as 250 watts when I shut it down.

My batteries (only about 460 amp hours) were full at the start, at nearly 13.50 volts. I ran AC on 'low cool' for about 100 minutes, my battery packs dropped to about 13.00 volts during the AC run. That's about 40% SOC remaining, and the average running voltage was perhaps a bit less than 13.2 volts.

With average delivery voltage around 13.2 volts, each "100 Amp hours" of "12v" LPF capacity used within my operating range 20-98% SOC corresponds to about 1300 watt hours. (Lead acid batteries contain less power per 100Ah, maybe around 1200 watt-hours, due to the slightly lower power delivery voltage.)

So roughly 60% of "460 Amp Hours" was about 276 amp hours consumed (3588 watt hours in 100 minutes). The power from the batteries was roughly 2000 watts continuous, and a lot of that was "spent" the 120-VAC inverter. I saved remaining 20% usable battery capacity (preceding my personal limit of not going below 20% SOC) for night time and early AM uses.

The average consumption of this older AC unit, running "low cool" in 90 degree temps, was probably around 1600-1700 watts.

[Bill]

I'm truly impressed!

Bill

[rich2468]

Thanks for sharing your "real-world" experience and background of all the conditions.

I believe ambient temperature really makes a huge difference in the power draw of our AC unit's. Much more so than later model year efficiencies increases might negate (I have a Mach 8 Cub Plus produced in 2020 for reference).