Bodge Charger 2 was developed from a combination of the original Bodge Charger (circa 2020) and lessons learned from ACDC (a very successful low ground clearance racer best suited to tarmac / concrete / flat and smooth short grass circuits, but some of the tracks we race on throughout the year can be held on rougher ground such as bumpy fields or meadows with medium to long grass. So Bodge Charger 2 takes into account all the lessons learned from these two Hacky Racers and incorporates them into the new Bodge Charger 2. These first set of pictures show the original Bodge Charger Hacky Racer as it was in 2020/21 at the very first Scrumpy cup and then at fully charged Live at Silverstone.
I also wanted to see what could be improved on regarding power, traction, stability, differential and batteries and have addressed each of these topics in the design. So I've now included full suspension (independent on the front, single swing arm on the rear), twin 2kw motors one on each rear wheel (split rear axle), electronic Diff, and a 48v 12s EV battery module from an eGolf.
Construction
Motors
Bodge Charger 2 has two MY1020 motors, one fitted to each half axle as seen in the photos. These motors are one of the most common type used for Hackys, they are 2kw 48v motors primarily designed for scooters etc and work well when matched with a cheap AliExpress 1500w 48v e-bike controller. The motors have been modified to provide more cooling airflow through the core of the motors by drilling out some of the vent holes to 6mm.
In Bodge Charger 2 the 2 motors are used independently to provide an electronic diff capability. In normal operation only one motor is driving at any one time, the other is left idling; which motor is providing drive is determined by a combination of steering angle and lateral G force. In a LH corner the RH motor will be providing drive and vice versa for a RH corner, drive always being provided to the outside wheel (typically having the most traction) which is the opposite of what a standard diff on a car does.
Motor Drivers/Controllers
Hacky Controller
Brakes
Batteries
The battery module is a single 12s pack originally from an eGolf EV. As you can see from the photos I've removed the original BMS board and split the pack into two 6s configurations. The battery as it comes is made up of 12 standard 4.1v Li-Ion cells housed in a sturdy metal container with a BMS PCB fitted on top. But seeing as I already have a powerful Dual 6S balance charger, then it made sense to split the pack into 2x 6S modules and get rid of the redundant BMS PCB and just charge the pack in balance mode as I normally do with my old 6S LiPo packs. So I wired up the pack as 2x 6S modules and connected balance leads to all the cells so that it would connect to my charger. To use the pack in its 48v 12S mode then all I needed to do was to connect the two 6S sub-packs in series again for racing with an XT90 adapter I made up.
After my first round of testing at Footfest 24 I discovered that the Li-Ion EV module voltage sagged drastically during race conditions and after only a few minutes racing the voltage under load dropped low enough to brownout (power down) my ESP32 controller. After that I replaced the battery pack with the standard 2x 6S Multistar LiPo's I had as spares and all my voltage sag issues went away. Bodge Charger seemed to have more punch and power after swapping the batteries over to the old LiPo's, so the only conclusion I can draw from this is that the Li-Ion EV pack is no good for racing. Well, that's what testing is for!!
