I have been wanting to finish this project for some time and now I have.
I got some new tools for the job that I was lacking. A better soldering iron with a long tip, a solder sucker, and some connectors.
First I cut a hole for a car power adapter.
I then attached the power adapter with a washer on the front so it will not put out easily.
I then took my spare charger and used the solder sucker to take out the LEDs.
Next I put extension wires in it's place so I can route them where I want them.
Everything seem to be working ok.
I drilled 3 small holes above the power outlet and installed the charger's LEDs.
Green for charged
Red for Charging, and the yellow is for if there is a dead battery.
After cleaning up some of the internal wiring and making an adapter for the alligator clips that clip onto the batteries I gave it a test run. The adapter can also be changed to connect to other types of 6v and 12v batteries.
Later I will also put in a charger for my smaller batteries with a special connector, but right now this is what I really needed for long events so I always have fresh batteries waiting for the drive system of R2-CM. The gonk is also strong enough to carry 6 extra spare 12v 7amp hour batteries inside of him.