I'm new to charging li-ion batteries and have read about house fires etc. I was thinking of building a slate box to house my charger in - with no lid. Has anyone else done something similar or am I being over cautious.
Nope, not that crazy. Though some people just use a pyrex pan, which would probably suffice.
3x layers of 1/2" drywall, drywall in the lid doesnt seal with the drywall in the base, and there is a brass vent stuffed with aluminum screening to arrest any flame as hot gasses would vent. Working on adding a panelmount XLR for feeding power though, and even a usb connection for the datalogging portion of the charger. Hooray "I'm bored... it'd be a good idea if..." projects.
No problem, in reality anything you line with even 1/2" of drywall would be fine. I took a propane torch to a scrap piece of the drywall after I built that. The paper had a hole burned in it, but it self-extinguished (treated to do so, no doubt) and I heated the exposed gypsum until there was a noticeable orange glow from the gypsum itself, which stuck around for a few moments after I removed the torch. The backside was only slightly hotter then I'd like to hold my hand against (120-130F, estimated with calibrated fingertip)
I then realized that my box was severely overbuilt