boondocking ac

[nemoskull]

they called me a mad man.
they said it couldnt be done.
untill i did it.

kinda sorta. arctic king 5k btu ac, hf 1500w inverter, 3 nissan leaf batteries. 200w solar. 490 watt draw running.
battery is 132 amp at 11.7ish volts, 1500 Wh area. running test now to see actual Wh from inverter.

[RJ Howell]

Ya, I'll follow along.

Your 11.7ish scared me at first, but then realized... I have no clue what that means on your batt's. Very curious of what the spec's are on those..

What are thinking for a run time? I'm thinking 4hrs with nothing else running and not pushing it.. Yet again, that's constant running which we know it doesn't.

Is the 490watts on energy saver?

[nemoskull]

no, the 490 is on full. havent checked the low cool setting, but low fan actually draws more, like 10 watts more or so.
voltage is avrage, start at 12.45v, cutoff at 9v, 80% used at 10.8v when inverter cuts out. ac is mounted in the trailer, with vents for intake and exhaust. total run time is 1.5 hours at 100% duty cycle.
thinking about adding a water sprayer.
730 Wh from the inverter.
did have a window unit that pulled a nice 350w, but that one is gone.
total 200w on the trailer, at 2pm, im pulling in 4.5a. room for a third panel. (edit, 4.5A @ 12v-ish)
salvaged nissan leaf cells, no bms, don't need one. started at 0.04 volt difference, measured a few months later, 0.01 difference. i got 2 batterys from a generation 2 nissan pack and 1 from a generation 1 pack. eight 16 gauge wires per terminal stay slightly warm at 500w. length is about a foot and a half. the terminals on the inverter are warm tho.
im just super jazzed this actually works, i figured it would but i was worried about the ducting.

final install
pics
skeleton showing cut out for intake/exhaust. there is vents on the nose too.

[RJ Howell]

no, the 490 is on full. havent checked the low cool setting, but low fan actually draws more, like 10 watts more or so.
voltage is avrage, start at 12.45v, cutoff at 9v, 80% used at 10.8v when inverter cuts out. ac is mounted in the trailer, with vents for intake and exhaust. total run time is 1.5 hours at 100% duty cycle.
thinking about adding a water sprayer.
730 Wh from the inverter.
did have a window unit that pulled a nice 350w, but that one is gone.
total 200w on the trailer, at 2pm, im pulling in 4.5a. room for a third panel. (edit, 4.5A @ 12v-ish)
salvaged nissan leaf cells, no bms, don't need one. started at 0.04 volt difference, measured a few months later, 0.01 difference. i got 2 batterys from a generation 2 nissan pack and 1 from a generation 1 pack. eight 16 gauge wires per terminal stay slightly warm at 500w. length is about a foot and a half. the terminals on the inverter are warm tho.
im just super jazzed this actually works, i figured it would but i was worried about the ducting.

Still a bit behind ya.. You say 490 watts, then say 730 watts... I'm assuming all in, you're drawing 730 watts. Is that the AC unit alone or something else running?

[KTM_Guy]

What was your ambient temperature while testing?

[Pmullen503]

Sounds like you are running this setup close to capacity. I assume these Nissan modules have a built in balance charger. You should be careful with this system until you are sure it's safe. Lipo fires do happen. Especially when running close to capacity.

If the modules have the factory BMS built in they are probably pretty safe.

[RJ Howell]

Did a little research to catch up here. Let me know if this is correct.

The Nissan batteries you have are 7.6v @ 64ah each. So 2 in series is 15.2 @ 64ah and the final paralleled in to a final of 11.4v at 128ah. 1,460 watts. From what I've seen so far, most sellers only claim 80% capacity left in them. I see these at around 1,170 watts +-

Ya, 1.5 hrs sounds like max'ing them out. Yet a bit scary how I got there...

[nemoskull]

RJ: 490 watts is ac draw. 730w is watt hours from 12.45v to inverter LVC.

KTM: no real testing of cooling done right not, no idea of temp. not super hot. ill do a actual cooling capacity relative to battery capacity later when i have better information. (inside temp, out side temp ect)

PMullen: no BMS. and batteries are not running at near capacity. the cells are rated for 3c discharge, and were tested to 1.5 charge (cus charging a 33a cell at 50a was the best i could do, amp wise) so 2s3p works out to 200a @12v if my math it right. but yeah, these batteries ability of dump out power should not be underestimated.

R: yes, thats the math i got as well, tho the guys on the nissan leaf forum report turtle mode at 3.6v, and cut off at 3v a cell for the car, and 2.5 a cell for absolute lowest voltage before damage. from what i can gather, 3.6v a cell (right at inverter cutout) is 80% capacity. ill know more later when i can get figures on the amps going in. im pretty sure im not getting the full rated capacity from the factory since these are used.

[noseoil]

I'm thinking all of the battery & inverter heat would be better if it was outside the shell (tongue box perhaps?) so it didn't add to the heat load. This is a BIG system for a teardrop size camper. Too bad a smaller capacity AC unit (2000 btu?) isn't available at a reasonable cost for campers...