Wrong forum for sure. Try a Power Wheels forum for more helpful information.
The connector looks like 4 pin flat trailer connector. You are only using 2 pins so you could put any properly rated connector there. Search "10 gauge 2 pin quick disconnect" on amazon that should plug into many trickle chargers, get a 6v one. When you buy a new battery it will probably come with a similar connector, with a fuse under the plastic cover.
If you have a car charger with a 6v option hook it up to make sure you aren't sinking money into something with many issues. If you need motors and a battery a new one may be cheaper.
The connector looks like 4 pin flat trailer connector. You are only using 2 pins so you could put any properly rated connector there. Search "10 gauge 2 pin quick disconnect" on amazon that should plug into many trickle chargers, get a 6v one. When you buy a new battery it will probably come with a similar connector, with a fuse under the plastic cover.
If you have a car charger with a 6v option hook it up to make sure you aren't sinking money into something with many issues. If you need motors and a battery a new one may be cheaper.