RC Car - 6 Wheel Hack

This was a 1 day build when I was bored at home.

I wanted a Radio controlled vehicle with 6 wheels, and as cheap as possible. So I bought 2 cars sawed one i half solvent welded the back end to the intact car.

The parts:

• 2 cheap rc cars(mine was Topraiders Tiger(Bionic) )
• Some legos
• 2 li-po cells
• Soldering iron
• Wires
• (some duct tape.......)
• Acetone

I had some li-po cells laying around from an old laptop battery. The car takes 4 AAA(1.5V) batteries in series which equals to 6 volts, and a top speed of 12km/h(7.5 mph).

2 li-po(3.7V) cells in series gives you 7.4 Volts and therefore extra speed out of the motors and the benefit of rechargeability. (I charge mine using some alligator clips and a 5v cheap battery charger)

1. Solder on the 2 li-po cells with some wires, connect one end to the negative terminal of one cell to the positive terminal of the other cell. Then add a red and black cable out ( I added a snap-in-clip-thing for easier removal)
2. Take out the AAA-batteries and find the positive/negative terminal from the old battery pack which leads to the PCB. Solder a new set of wires to the li-po pack.

I took the soldering iron and removed the motor wires from the PCB of one car, then sawed-off that car in the middle so the whole back-suspension system came out as one piece(ワンピース ;). That's because the hinge should still be in use so both back-ends(motors) is held in suspension.

I gladly found out that the cars chassis was made out of ABS plastic so I could solvent weld them with Acetone.

1. I took some legos that seemed suitable as a linkage between the two, guesstimated the fit and fastened the legos to the cars with acetone, aim for as much surface area as possible so the solvent weld can make a strong joint. I used the battery hatch from the sawed up car as re-enforcement at the bottom och the joint.
2. Take the connections, of the motor that is attached to the end of the 6 wheeler, and solder them to the PCB pads shown in the picture.

Make sure that your new vehicle is strong enough for the first test run, if you feel like the joint of the new back-end isn't gonna hold up, add some more legos(ABS pieces) with acetone to strengthen the cars rigidity.