1. Adequate cooling so I can experiment with motors drawing up to 30 amps.
2. Proper insulation and protection when mounted.
3. Easy interconnect.
- Overall View
- Close up. Front and back
- End shot showing female bullet connectors.
I decided to solder the PWM cable on directly and the length given with the kit seemed about right although I would have liked the cable to be a more flexible type that what was supplied. Perhaps something like what comes with a Naza kit - silicon rubber type insulation.
I also decided to solder the FTDI serial interface pins permanently to the board since I'll likely be experimenting with different configurations and there will certainly be firmware updates.
I soldered the female side of 3mm bullet connectors for the motors directly to the board in a similar fashion as DJI does on their ESC. On inspecting the ESC32 circuit boards the motor output pads appear to have enough area bonded to the PCB substrate such that they'll be plenty strong. Of course plenty of solder was flowed around the connectors. Each individual connector has a short length of heat shrink tubing around it for further insulation as well as the overall heat shrink around the entire ESC.
I fabricated a heat sink of 1.5mm think aluminum which was then glued using Arctic Alumina 5 minute thermal epoxy directly to the tops of the FETs. This is the same adhesive used to attach heat sinks to Kontronik Jive 120 ESCs. With application of heat it can be carefully pried off if need be but otherwise is quite a robust connection - both thermal and mechanical. The underside of the heat sink not glued to the FET is covered with thin double sided tape which has not had the plastic protective material removed from one side. This is to ensure the heat sink doesn't short out or contact any circuitry.
The entire esc was then wrapped in clear heat shrink. This is standard flexible heat shrink material and not the hard thin material often used on batteries. I debated whether to cut out a window so the heat sink on each side could have direct contact with the ope air rather than being insulated by the heat shrink as with most ESCs. I couldn't find thermal insulation data for the heat shrink but it seems clear that the more of the heat sink that can be exposed to the open air the better cooling so I cut out a window of heat shrink on each side of the ESC so as to expose about 3/4 of the heat sink area.
A few photos are attached.
That's my first cut at it. I hope someone can leverage this and improve upon it!
Cheers,
Wingspinner
Ron Curry