Overcautious, maybe. But I don't intend to be the one that is homeless with a fire to blame.
Last night I read a thread about a guy that had a battery charging and the end blew off, shot a two foot flame out and caught some stuff on a table on fire. Then I got to sketching a couple designs. I was going to make it out of steel so I could play with my welder until I remembered that aluminum box tubing that was in the shed.
The tray was cut off the end of the rectangle part and had one side hacked off. I smoothed it all down with a flap wheel on the grinder and hit the whole thing with that flap wheel to get rid of the scratches on it. I thought about paint but then I realized that it would just chip and start looking bad in no time. Painting it isn't out of the question, I'm partial to Krylon flat black and now that I think of it, that stuff does hold up pretty good.
I only intend to use the box when I'm not going to be around for a while, when I am I can just touch the battery every once in a while because I'm sure they start getting warm long before they blow.
I believe cell phones are programmed to stop charging once the battery is charged so that shouldn't be a concern. I did read on here that these
batteries need to be pulled off the charger soon after they are done charging because they keep accepting
juice until they can't take it any more.
Grenade, not likely. It has close to 1/8" of breathing room between both sides and around 1/16" above the top edge of the tray.
I've seen cordless drill batteries turn into paperweights from charging all the time too. My dads old Makita would last for about 10 minutes worth of drilling on a fully charged battery. That's why I have DeWalt with a cord on it now. I don't care for those keyless chucks either because you have to throw on a leather glove and about burn it with the drill just to get it to grip a drill bit tight enough. I learned what not to buy with that drill.