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Old 03-16-2006, 03:30 PM
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Power Caps & Schottky's ???

Hi all.

I'm a nOOb when it comes to R/C.
I bought a Power Cap for my TT-01 and I just figured out how to connect the damn thing.
The ESC I use is a Novak XRS, from a Team Losi car.
When I bought the ESC there was some sticker things saying DO NOT USE SCHOTTKY Diodes with this ESC.
Are schottky diodes the same as a Power Cap??
Anyone with the same ESC??

Any help is much appreciated.

Cheers
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Old 03-16-2006, 03:48 PM
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Originally Posted by JohanZ
Hi all.

I'm a nOOb when it comes to R/C.
I bought a Power Cap for my TT-01 and I just figured out how to connect the damn thing.
The ESC I use is a Novak XRS, from a Team Losi car.
When I bought the ESC there was some sticker things saying DO NOT USE SCHOTTKY Diodes with this ESC.
Are schottky diodes the same as a Power Cap??
Anyone with the same ESC??

Any help is much appreciated.

Cheers
Schottky diodes are not the same thing as a power cap. I'm not an electrical engineer by any means, but the basic idea with the Schotkky is that it's used to prevent big spikes of reverse current from coming back down the pipe from the motor to the speed control, particularly when you back off the power.

The reason that you can't use this with an ESC like the XRS is because it will create a short circuit if the ESC tries to apply reverse voltage to back the car up. Most racing ESC's are forward-only, so this isn't a problem and that's why they recommend the Schottky - it reduces heat, voltage spikes, etc.

The power cap is used to buffer and smooth the input power flow coming from the battery to the ESC. Smoother voltage and less peaks/dips on the input side also helps to keep the ESC cool and safe. There should be no problem using a power cap with pretty much any ESC although many are ok without them.
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Old 03-16-2006, 03:48 PM
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Schottky diodes can only be used with forward-only esc's, that's why your esc says not to use them. Power caps are electrolytic capacitors, which are different from diodes.
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Old 03-16-2006, 04:28 PM
  #4  
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ok, thanks for the input.
So installning a Power Cap would only do me good?
Iv'e read horror stories about the XRS ESC, and that bothers me a bit.
I should have read up on the XRS b4 I bought it I guess, but now its too late.
I have this little CPU Heatsink and Fan from an old PC, that I'm planning to put ontop of the ESC to help it cool down.
In another thread I asked about motors to go with the XRS, and since i'm only going to use my R/C's to bash around parking lots I decided to go for a 19T motor.
Enough torque for my buggy, and enough speed for the touring car.
The motor is a ASSOCIATED REEDY 513 SPEC 19T STOCK MOTOR.
Anyone with good experience with the XRS and this motor???

Cheers
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Old 03-16-2006, 07:28 PM
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I've used an XRS with some 19T motors before. Seemed to be ok. Obviously, if it does get really hot, give it a little time to cool down between battery packs and so forth. Other than that, I think you'll be fine with it. It's certainly nice and compact and easy to fit on a chassis. Hopefully it works well for you.
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