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Originally Posted by Matt Krass
While at the low current draws involved with R/C motors the FETs are probably dissipating considerably less heat, I see no practical advantage to turning them off, and there's always that fluke power surge. I'm curious Andy, do you gain anything significant from removing the fans?
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First and foremost, the advantage is a reduction in both weight and hight. If I am putting a Victor on a car it's because I intend to make it go fast. It might not seem like much, but one of those fans is hefty. Weight negatively effects every performance aspect of an RC car. So if it isn't mandatory, it goes. Losing the fan also cuts down on the victor's height, which makes it a bit easier to package. The victors are already much larger and heavier then typical hobby speed controllers and demand a larger battery source, so any weight or size reduction makes a big difference.
Using a Victor means trying to make up the weight gained from the extra cells needed to run it. Even with the increased capacity and features of the victor the extra weight makes it a hard pill to swallow. The price, which is to say free, makes up for a lot in my mind but it is still an hard trade off.
After that it's just the shear pointlessness of the fan to start with. On a FIRST robot running a full 2 minute match, the Victors running drive motors might get toasty enough to need the fan. Running one motor moving less then 5 lbs and there is no way that the FETs will produce enough heat to warrant a fan. They just won't. Honest. The popular notion that removing the fan or not having one running for ever moment the victor has power applied annoys the heck out of me because it's so utterly false.
I've run many small RC cars with a victor/drill motor or FP motor setup and have never once found the victors to be anything but stone cold. I have never once seen a Victor fail because the FETs overheated (short circuits not withstanding) Heat is simply not the big killer issue that people make it out to be in regards to the Victors. If you are really worried about it just position the victor so some air passes over it through the body, but don't bite you're nails about it.
The fan really is overkill on an RC car. Ditch it and worry about balence and where to stick the extra battery pack.
-Andy A.