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A/C for my battery compartment
I have an issue.  

I had a LiFePo4 battery system I built myself.    Realizing then that keeping the batteries cool would be a challenge…I built they system so that each of the 16 battery cell packs were placed so that there was 1” between them.

Last summer I had to replace my battery.    The new battery is built complete inside a single box.  It’s pretty tight in there.

After many issues and long lead times for parts and replacements, I finally had a full function battery with a BMS and Balancer.    

This winter, I have discovered that as I turn the heat on in the morning (all electric propane) the temperature of the battery starts to climb quickly.    Typically, the batteries start the morning at about 3-5 degrees (Celsius), and heat up by 8-10 degrees (Celsius) within about 45 minutes.    

This is fine for the winter.  In fact, great since LiFePo4 should never be charged below zero (Celsius)…so, I get them warmed up before the sun rises.    But..what about this summer?   LiFePo4 should not be discharged above 40 (Celsius..of course).   So when the temps are up to 105f, running the A/C unit would simply cause the BMS to shut the whole system down to protect the battery.

Any ideas so a small A/C that will fit into a space of 6”x4”x3”?    I need something that draws very little power, and can keep that compartment cool(er).  

I rarely run A/C since the swamp cooler does a great job most of the time.   But, in the monsoons the A/C is the only choice because the humidity gets to be pretty high.

Anyone have ideas?
1989 Honeywell motorhome
Ford E350 chassis.  460 engine
Interesting question !
That would be the smallest AC I've ever seen,,,and I haven't seen one yet.
So , maybe a fan ?
Is gaining some altitude a possibility ?
Ahhhhhh ! Of course !
It's own 12v fridge ...
stay tuned 

 Weirdo Overlord : FMS Fleet Ops , Awards , Badges ,  aka Tamerlane the Impaler Mod.
Hey Roamingcat,
I’m not sure if it was you I met at the pirate camp. I can never remember names rolling cat catrolling, two dogs and a cat, two Cats and Doug, the new and improved 2 cats with a Doug and Pauline. But if it was you, that’s too bad you didn’t mention it I mean AC unit that size is by definition impossible, way too small. They make a 12 V breeze, breeze two, give me more money breeze improved but …it’s not practical in any way, shape or form in a system.
I used a little bit of space with an insulated negative space Going to the outside and insulated inside space with the battery compartment comprised of off all three of those kind of designs. And I have an exhaust dump tube that was popular in the 60s with the boys that wanted to have a loud sounding engine and I can electronically engage the dump tube and open up a whole 3 inch stainless steel pipe hole to the underside of the vehicle and affectively ram air into the battery component. The issue with that is it can only be used when it’s dry and you’re driving over dry Road. Lol. Although I can open it up and allow it to pull naturally air from the underside of the van, which should be colder, up into the insulated part of the van and drawn out by fans. Fans, computer fans, are your friend at least two blowing at different angles very different locations And you know you’re not building airtight so nature will find a way to suck air from somewhere but try to plan it out just like try to plan out your battery management system.

You know everyone focuses on charging and speed charging and how fast it’ll charge you and what the C numbers are. Me? It’s the protections over and under voltage protection on a lithium system is essential. Running them at 80% capacity following the 8020 rule is essential and it’s not as easy as just writing it down and putting it in. I’m just spent now 3/4 months dialing in the system so I know what it’ll do under which conditions and when can I be, you know; “who cares turn on the air-conditioning full blast I got lots of sun,” and “I got to be careful.” A lot of this comes from trying and doing so it’s essential to have protection on the batteries and ensure you have protection, test the batteries to make sure they have what they say they do and then the worst you can do is go into protection mode.

Remote temperature meters are cheap and accurate enough. For what it’s worth, and your mileage might very. I got stuck coming across Northern California when the temps near the Robalas vinery was 39 42 C and I don’t have vehicle driven air. Hadn’t notice this fact till then. The Green A/C machine 12 volt on the roof was used to cool the vehicle, after I had driven for five miles at 85mph with the windows open. It didn’t protect or go into protection mode. I didn’t use the dump tube, hit the 21degrees button and It kinda worked.

Mount your awning on the same sides as your battery bank. This keeps the sun off the battery side.

Sent from my iPhone using Tapatalk
[-] The following 1 user says Thank You to Scott7022 for this post:
  • rvpopeye (02-01-2023)

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