I’ve been storing 2 of my Bonkas in a sealed cooler indoors for about 4 weeks (at storage voltage). When I opened the cooler, I was overpowered by a very strong smell of acetone (nail polish remover). There is no puffiness, and I don’t see any signs of punctures. Are they dangerous?
Yes. I smelled this same smell right before it blew up on my leg. But I was over VOLTING them on a riding mower LMAO!
LiPos have a sweet epoxy-ish smell, like permanent marker with some acetone mixed in. If you smell it, the battery might be perforated. However you’re supposed to store the batteries in a ventilated container so its hard to tell.
Coolers are not a great storage box because they are flammable and not ventilated.
The batteries are in fireproof Lipo bags, just sitting in the cooler. Originally, the cooler was meant to keep the batteries out of constantly changing temperatures, out of the sun, etc. while being transported. Can a lack of air circulation potentially damage the batteries?
I regularly read that batteries can be kept in fire safes, which aren’t ventilated. How important is ventilation?
Any sealed container is a really bad place to store lipos. They become pressure vessels that will explode very violently if the lipo goes up, especially lipos this big. Very rare for it to occur, but better safe than sorry. Have had a friend or two lose their house / stuff because of it.
I use ammo cans with the seals removed and/or a hole or two drilled into it. This allows the gas to vent but contains the heat decently well. Lipo safe bags will NOT contain lipos of this size if they go up.
I will use a vented container now, but still not sure if that smell is normal (and possibly just collected in a more concentrated way because they were in the sealed cooler), or if I should be concerned about using those batteries.
For the Bonka batteries, what is the storage voltage recommended?
If they’re perforated, it’ll be a sweet smell. If one is punctured, you can usually see a cell with a lower voltage with a cell checker or on your charger with the balance lead plugged in. As long as they’re within 0.1v of each other they’re probably fine.