OK how about this solution. Make like a small kennel outside, place battery in there and run cables from charger and feed to bedroom from there. That way you can still use the battery and charge with no risk of spills or worse in your bedroom. If charger wires and feed wires are all good connections there shouldn't be any sparks. Use good fuses at battery end of all cables. Make a fused distribution board in your bedroom with multiple outputs all fused nice and safe.
This I'm sure will appeal to your sense of adventure and general playing:thumbs