Off grid staying cool???

[Snikwahjm]

We have solar powering a fridge and a fan. We are not cool. The temps are in the 90s and the humidity might be 99%... what are you doing to get cool?

[sternwake]

Not Much hope of Evaporative cooling with 99% humidity, looks like you are requiring a more powerful fan to exchange outsie air for inside air, or a more efficient way of doing so to keep the vehicle interior no hotten than outside ambient temps.

While I tried this with much less humidity, I put a cement mixer pan with about 1 inch of water in it, in front of my intake fans, with a sarong hung directly in this intake fan flow, with the tails of sarong in the pan of water.

The water after 2 hours was surprisingly cool and my IR thermometer showed the sarong was over 20 degrees cooler than the cabinet 16 inches away from it, and the interior of my van was noticeably cooler that outside.

[Blacktank]

ac is the only relief for that weather,fan and mister/spray bottle will take you to from i wish i would die to unbearable
when i lived in northern georgia it would get like that and i wouldnt want to leave the shower
https://www.walmart.com/c/kp/water-misting-fans

[justjim]

I run a pair of 5000 BTU air conditioners.

[RoamingKat]

Only when the sun is high..I can run my little AC off solar panels and battery. But...when the sun is low, I have to stop that.

Nothing will run 110 AC longer term, except a generator or plugging in.
Sternwake can give you the math...but, as a quick rule of thumb...110 volts converting to 12v...just shift the decimal over one place.

SO...If it take 15 Amps at 110. It will take 150 amps at 12.
Rough first approximation. But, the number is too high to ever get more than an hour or so without a generator or plugging in

[Blacktank]

Jim measures his solar in kilowatts,you can see him from space and talk to him too,right before he focuses his death ray and turns you to cosmic dust

[Snikwahjm]

Hey even the fan is overpowering the solar today

[RoamingKat]

Still not enough....Jim has 1.4 KW.

Or. 1400 w. At 12 V. That is a max of 116 amps. With perfect alignment, in the high summer. (Amps = watts/volts).

Still not enough to drive a little 120v 5 amp AC. It would take 50 amps at 12v. (Don’t forget to count the parasitic cost of the inverter). IF I remember he has 460 amp hour Lead acid technology...so only 230 amps really available on those batteries....

See....the math still says a generator is necessary to run it off grid.

To do this with solar only...you need to generate 50 amps per hour..every hour.. with the sun shining directly onto perfectly aligned panels all the time.....even that would only be for the 2 hours as the sun reaches its zenith...then you need progressively more panels as the sun approached zenith and descends from Zenith. What about 5pm till dark? Maybe you can still get 30 amps at 12v. BUT..that is only 3 amp 120v. The batteries have to do the rest....for 9 hours overnight....or 450 amps till dawn. Not enough amps available to recharge the battery and drive the AC on day two, and it is down hill from there. Each day the batteries are more drained...till in just a couple of days the batteries are too drained to handle the AC at all.

Can’t get around the math. Have to run a generator.

[Snikwahjm]

Well I figured out how to get cool. I armed the grand kids with spray bottles and one from the fridge for me... AND I might just be the best and wettest grandma on the block.

[Cammalu]

Snik, start driving north till it isn’t hot!!


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