A fridge needs ventilation or the coolant compressor will heat up. If the bear box is WELL ventilated (most are definitely not), then putting a fridge into one will not work well at all.
As it re-compresses the coolant the heat that produces travels through basically a radiator that a fan blows to help cool it before sending it back into the fridge for decompression again where it cools even more. If the enclosed space doesn’t allow cooling prior to reentry, than its working against itself just like if an LC radiator had a completely covered grill.
If your bear box is a cage style, then ok. If an enclosed space...don’t do it. Good way to fry a fridge, or at best, run your battery down from a constant on state (or frequently on).