I am currently working on a project when I need to step down 12V to 6V. This 6V will serve 3 motors. The motors pull 4 amps, 1.5 amps, and 1 amp when they are each at full power.

I am having trouble finding a regulator to step the voltage to 6V while still being able to handle high currents.

What options do I have? The simpler the better!

 

In addition, the battery is not attached to an alternator. The battery will slowly lose voltage.

 

A linear regulator will dissipate huge amounts of power, which means huge heat sinks. (6V*6.5A= 39Watts)
You need to buy 12V motors, or use a switch-mode buck regulated DC to DC voltage converter.

 

Mike is right, you should try a DC-DC converter instead of regulator. It can be designed for low voltage and current ripple, so it proide to you 6V regulated output.

 

or use (2) 6 volt batteries...

 

or use (2) 6 volt batteries...

Provided you charge them one after the other, or using two 6V chargers. Putting batteries in series, and drawing unequal load current from them, and then trying to charge them in series will damage a battery in short order...