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Revision as of 14:32, 25 June 2017 by Rew (talk | contribs) (Software)

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BESC -- BitWizard ESC


The BitWizard ESC is based on Benjamin Vedder's VESC. The BESC has as advantages that the FETS are better positioned so that they can be cooled. A disadvantage is that it is slightly larger so it takes a bit more space.

getting started


Power electronics is finicky stuff. Create a short somewhere and things blow up spectacularly immediately (or not (*)).

The BESC shuts down permanently when:

  • you connect the two sub-boards shifted one pin. Don't ask how I know.
  • the connector between both boards comes

loose. if your enclosure does not force the boards together, consider a tiewrap to keep them together.

  • In cardboard box, riding at 15A continuous for 20 minutes causes the board to overheat. Or at least enter thermal slowdown.

(*) it blows up trust me, just maybe not spectacularly.

connecting the motor and the battery

The power board needs connections to the motor and to the battery.

There are three obvious places for the motor wires. Right? Those are near a TAB for a FET. You MAY connect to that tab as well. There are 6-and-a-half feet of the other fet nearby. The leftmost is the gate. Do not short there. The middle, shorter one is the V+. Do not short there. That leaves five legs of the transistor that you're allowed to solder to. This last option is the easiest. Before powering it up: PLEASE check that you don't have any shorts. Check for shorts from the motor wires to both supply pins and to the gates of the highside FETs.

If you have the power-board right-side-up, you'll have the battery connections nearest yourself, the pin header on the right. The left battery connection is the battery +, the right one is the ground. Double check: The battery + is connected to all three tabs of the high side fets. Those are the tabs nearest the PCB edge. The battery - is connected to all three shunt resistors. (according to your multimeter: both sides ;-) ).

Keep the capacitors as close as possible to the board. Consider soldering them between the ground side of the shunt resistors and the tabs of the high-side fets.

The back of the power board is meant for cooling. At 20A max current, and riding 18 minutes at 15A I heated my board into thermal slowdown yesterday night. I should get a bit better cooling for my own bike.

If you're going to cool that side of the PCB, make sure your wires do not protrude through the PCB, or short against the heatsink.

Software and updating

I'm on branch "cr" of rewolff/bldc-bw.git on github. Doublecheck that conf_general.h has "BW2" as the hardware selected.

I have never used Benjamins bootloader. Connect the board to the PC. Next power up the board. Now press-and-hold the boot button, press-and-release the reset button, and release the boot button. Now the CPU is in USB bootloader mode.

I use

       dfu-util -a 0 -D build/BLDC_4_ChibiOS.dfu

to upload new firmware. use

 make  build/BLDC_4_ChibiOS.dfu

to build the required file.

To control the BESC use Benjamins BLDC-tool software.