I've been eyeing a fire resistant cabinet like the one you show above. I'm going to have to re arrange my garage storage to make room for it though. In the mean time, I'm using a pair of these $28, 20mm ammo cans to store & charge batteries.
USGI 20mm AMMO CAN EXCELLENT CONDITION used. The 20mm ammo can is one of the most popular ammo cans available because of its high capacity to put virtually anything in it. Excellent condition ammo can that has no holes or problems.
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Instead of using holes with grommets for wiring, I use these XLR panel connectors mounted to the side of the cans.
Amazon.com: GDQLCNXB XLR Female Jack 3 Pin Panel Mount Jacks, XLR Female Socket Audio Speaker Microphone Connector 4Pcs,Silver Metal Housing : Musical Instruments
www.amazon.com
I store the cans on a concrete floor in a semi heated garage where the temps vary between 55 and 80 degrees. I also have a smoke/fire detector nearby and never charge unattended. When full with 4 batteries, the cans are too heavy to lift easily and I wouldn't try it anyway with one burning inside. I keep a rake handy which I can use to grab the handle of the can and drag it across the concrete floor and out of the garage should it become necessary.
Just how effective these ammo cans are at containing a battery fire is unknown. This isn't a perfect setup but I figure it will reduce my chances of serious damage should a catastrophic incident occur.