Airtight Battery Boxes

[Kent]

I've read posts here where someone has commented about the battery(s) getting warm or hot to the touch.

I am currently searching for waterproof containers to serve as battery boxes for my next build and occasionally come across ones which are air tight as well. This begs the question: how much air circulation does a battery need? Should a person install louvres in the box to promote air flow? And what about members who pack their batteries with foam to shock-proof them?

Comments appreciated
Kent

 

[MadRhino]

Batteries don't need air to work.
If it does need air flow to cool, it's a sign that its C rate (or capacity) is not enough for the controller Amp setting.

 

[qtipslea]

Batteries don't need air to work.
If it does need air flow to cool, it's a sign that its C rate (or capacity) is not enough for the controller Amp setting.

Just to clarify, if a battery C rating is enough for the controller amp setting, then even when being used constantly (stress), it will never heat up enough to need air to cool?

I should tell my boss that the battery on my forklift doesn't have enough C rating then. A few hours on that and boy I got a nice seat warmer.

 

[MadRhino]

Yep, your fork lift must have lead batteries, and pull alot more Amps that they like. Tell your boss to buy Lipo and a big controller, then you can enter a fork lift race.

 

[John in CR]

I like to use duct tape to make my battery packs extremely water resistant. As few continuous pieces as practical is the key. Duct tape is also a decent conductor of heat as far as good insulators go. In addition you minimize the air inside to virtually eliminate condensation. Then whatever your outer shell is can permit some air flow, so it doesn't turn into a solar oven in the sun, and more importantly it allows for drip holes at the lowest point in case water does get in. LFP managed to get my bike broadsided by a rogue Pacific ocean wave, and everything protected by duct tape stayed dry, and duct tape was the pack's only covering. Only the unprotected hall connector got a bit of salt water in it and put the bike out of commission for a few minutes. Sure it's not pretty as an outer cover, but duct tape is indispensable for battery packs AFAIC.

 

[dogman dan]

What type of batteries? Bear in mind you take RC lipo packs, and if one vents and it's contained good enough, it becomes what lipo packs resemble. Just a small hole to let the wiring out should be enough to prevent an overpressure getting really dangerous. A hole can be made, then taped over. Then it will blow the tape and vent if it must. I've done this with my ammo cans, that really seal up tight.

I have advised that people allow some air to circulate around a bms. The ping V1 bms in particular was notoriously warm in use. So smothering the bms in foam would burn em out.

Nicads get quite hot in use, normaly. Lead gets at least toasty warm. A ping warms up, but not much more than body temp.
Lipo can get quite toasty if run at 50% of the stated c rate, but not as hot as nicad in most cases. Insulating the battery box or just cusioning it with foam should be harmless. If the foam makes the batteries too hot, then it's the discharge rate that is the problem. Nicad and Nimh I would not insulate unless in the frozen parts of the world.