Vesc Modifications

Extra capacitors

You may want to consider larger 100v main bypass capacitors. Especially if your battery to esc wires are long, tying + and – cables together will decrease inductance. The stock caps are only rated for 63v, so if you are running 12s you may want to consider upgrading for this reason alone. The larger caps filter the low frequency noise and the ceramic caps the high frequency stuff.

A useful analogy is think back to when you turn a tap on and off quickly, your pipework will jolt from the momentum of the water being halted. This excess pressure is like a voltage spike when you mosfets open and close. Now imagine connecting a rubber bladder to you pipe work near your tap. When you close your tap rapidly the excess pressure would fill the bladder. Also when you next open the tap that excess pressure will be released very quickly reducing the water flog lag. This is similar to what a capacitor is doing, smoothing out the pressure / voltage.

TVS diodes

A TVS diode acts as a current shunt, if the voltage rises above its breakout voltage it will begin conducting to ground, the higher the voltage the more it will conduct. The uni directional diodes I use are Vishay 1.5KE62A-E3/54. Is important to match these to the voltage you are using. You dont want them conducting at normal operating voltage or failing to shunt at all because the breakout voltage is too high. Also remember to reverse bias them! You also want the diode as close to pcb as possible, i put mine here.

A useful analogy for these is having a safety valve in the pipe work next to the tap. Its designed to open relieving the excess pressure by dumping it into the sink when you close the tap. It doesn’t store charge like a capacitor, so is unless for smoothing out under voltage.

Cooling

You may chose to add heatsinks to the mosfets, the problem is most of the heat is sunk to the pcb, so the heatsinks wont be very efficient. Instead id recommend blowing air across the pcb. Ive used a high airflow sunon fan to blow air into the esc enclosure, the below photo is a top down view where the lid goes on, the air actually enter and exits from underneath (Deck side) The heatsinks have since been removed as they were pretty ineffective. The highest temp ive seen in logs is a mere 43c! that was on a warm summers day too. This is partly why i also chose to run 12s, to keep things cooler.

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