Quote:
Originally Posted by BrianG
Depending on the ESC, it might have some type of voltage monitoring, but that would most likely be in firmware or some dedicated IC. Even then, this watchdog thing will only prevent the ESC from functioning, but the full battery voltage will still be at the drain and source terminals of the FETs.
Using higher voltage FETs would keep them further away from the actual voltage being used (best not to run anything at their max values). But if the current, slew rate, and rds-on are not equal (or better) as the lower-voltage FETs, you're not gaining anything. I would rather have FETs that are rated around 10-15% higher voltage than what you plan to use, but use ones that have higher current, lower rds-on, and faster slew rate for thermal reasons.
As far as construction, the method Castle uses to stack the power boards is pretty good. The brains are on top where they (hopefully) won't get as hot from the FET boards, and stacking is simple even with the heatsinks. With the MGM, the brains board might be heated beyond what I would like. Oh, and the heatsinks on the HV are nice since they contact BOTH sides of the PCB so ALL the FETs are cooled. The only layer that isn't cooled is the top one, but Castle puts an Al heatspreader on there. I might contact them to see if I can get an extra heatsink piece for that. The more I look at this ESC, the more I like it! If only they would make it work with pistol grip radios a little better.
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I found the problem about voltage with the Traxxas VXL controller which could be a nice 4S controller, but the thing won't do nothing if you plug 4S to it. I also like the HV110 design. The MMM could've looked like it.