New Power Wheels models have a built-in thermal fuse to keep the car battery from overheating during use. Older models used a removable 25-amp fuse to protect the battery from damage during use or when recharging. You should check the fuse each time you prepare to charge the battery to ensure it is good. You should also replace blown fuses before recharging the battery in order to prevent damage to the battery.
Unplug the battery from the Power Wheels, pull it out of the vehicle and sit it on the ground with the top facing up. You can see the fuse inserted in the top of the battery.
Pull the fuse out of the battery with your fingers or, if you can't grip the fuse, use needle-nose pliers to remove the fuse.
Examine the inside of the fuse. If the metal strip in the middle of the fuse is intact, then the fuse is still good. If the metal strip is broken, then you need to replace the fuse.
Insert a good fuse into the battery with the contacts facing down. When properly installed, the fuse sits below the surface of the battery.
Do not charge the battery without the fuse installed. You could damage the battery if you charge it without a fuse.