Narve led cordless lamp tech help

I have been given a Narva led cordless lamp with a faulty battery & i removed the battery (4.8 volt) & connected the power wires direct to 12 volts & it works ok (only had it on for about 30 seconds)

Inside there is a circuit board with a silver box on it that says it is a convertor to 8 volts from memory but i have no idea what everything else does

Before i make up a proper lead i was wondering if any electronic techs on the forum can make a educated guess if it will be ok running on 12v or if i will fry something inside (if so i wont bother making up a permenent lead)

Any help or thoughts would be appreciated

Regards Don