It's probably a Power Wheels. If it was me, since I can't leave anything stock, I'd rework the bracket so it would hold a motorcycle battery. Better yet, if there's room, I'd fab up a bracket for a small Optima yellow top battery. Sure, the battery would cost more than the car but it would run forever!

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-Evan


Benz Fleet:
1968 UNIMOG 404.114
1998 E300
2008 E63


Non-Benz Fleet:
1992 Aerostar
1993 MR2
2000 F250