At the end of 2019 there has been a congress held by CCC in Leipzig. Lots of accidents have happened, the throttle and breaking pedals were toren off, the BMS died, a frontal crash with a public bench has bent the steering wheel and much more. But let the pictures speak for themself:

Dead BMS

Probably due to overvoltage and EMV discharge from all of the drifting on the congress the BMS died. And it died in a strange way, the mosfets were connected just enough so that the voltage meter could measure 24V on the 50V battery? The replacement was a much stronger 300A BMS system

Charging the battery

Charging the bobbycar battery is an interesting task, you should not go over the maximum voltage of the pack but also you shoulnt get close to it as you might not be able to break in emergency situations at the beginning of the ride. The BMS could disconnect the ESC motor controllers in case of an overvoltage which would mean no current can flow into the battery and you have no breaking deceleration.

In the past I have always been using my 60V5A lab bench power supply but with this it takes around 30 minutes to charge from completely empty, which is way too long.

The good thing about these power supplies is that you can wire them up in parallel and increase the total current and power going into the bobbycar.

Sadly one of my first lab bench power supplies went up in smoke during one of such operations and I was able to capture the last time it went up and a mosfet leg exploded!

Let’s see what other ways we might find in the future to charge my beloved bobbycar!