12V Battery Charger

Can I use a 12V charger to charge my 12V portable emergency battery? The plastic casing of the OEM charger is defroming from the heat during the charging. The charger is rated at 13.9V 300amp. I like to replace the OEM charger with one that rated at 12V 300amp that I have. Will the 12V charger able to replace the 13.9V charger? The last thing I want to do is burning down the house.

I'd contact the manufacturer. If the charger is overheating, there might be a problem in the battery.