KDXRIDER.NET

Waking up an old discussion here. I'm thinking I want to add a small cooling fan to the back of one of my radiators. I do a lot of 1st/2nd gear crawling where I ride. I don't know much about electricity or if a fan like that even exists. From the forums I think I've picked up that our bikes (mine's an '05 220) are 12volt AC. Is that correct? What about Amps? I guess I'm looking for the specs so I can try an find a fan that is pretty much a plug-and-play. I'm not electrically inclined enough to do much more than that....Thanks dudes

Jason good to see you joined. If it is possible i'm sure someone on here will know.

billys04kdx200 wrote:Jason good to see you joined. If it is possible i'm sure someone on here will know.

Yeah, thanks for turning me on to the site....seems to be a lot of technically experienced riders here...looking forward to learning more about my bike!!

Small fans are DC and typically need close to 15 amps to run @ 12V, at or over 150 watts. But if you want to pursue specifics both KTM and Honda (for the CRF250X) have optional fan kits for their battery-equipped bikes. I'm think'n you'd need to rewind the coils, install a rectifying system and a battery.
Or you could go with a coolant additive.

kawagumby wrote:Small fans are DC and typically need close to 15 amps to run @ 12V, at or over 150 watts. But if you want to pursue specifics both KTM and Honda (for the CRF250X) have optional fan kits for their battery-equipped bikes. I'm think'n you'd need to rewind the coils, install a rectifying system and a battery.
Or you could go with a coolant additive.

Ehhhhh, sounds like more than I want to do. SO what about coolant additives? Does anything work that great?

Any 12v fan will work, AC/DC doesn't matter. Computer fan should work great, and are generally tolerable to major changes in power input.

I don't think so. A typical computer fan (power supply) is 12V DC and draws a paltry 0.10 - 0.25 amps. Even in the unlikely event that they might work in an AC or pulsating DC system, they wouldn't generate enough blow to knock a fly off of a matchstick, but... they won't work.

Computer fan motors are BLDC (brushless DC) motors. "Although BLDC motors are practically identical to permanent magnet AC motors, the controller implementation is what makes them DC. While AC motors feed sinusoidal current simultaneously to each of the legs (with an equal phase distribution), DC controllers only approximate this by feeding full positive and negative current to two of the legs at a time. The major advantage of this is that both the logic controllers and battery power sources operate on DC, such as in computers and electric cars."

If you tear a computer fan motor apart, you'll see the fixed coils wired to a circuit board. The circular magnet(s) attached to the fan blades rotate about that afixed configuration.

Computer fan motors are BLDC (brushless DC) motors. "Although BLDC motors are practically identical to permanent magnet AC motors, the controller implementation is what makes them DC. While AC motors feed sinusoidal current simultaneously to each of the legs (with an equal phase distribution), DC controllers only approximate this by feeding full positive and negative current to two of the legs at a time. The major advantage of this is that both the logic controllers and battery power sources operate on DC, such as in computers and electric cars."

Very cool! ha ha ha ha...

..they wouldn't generate enough blow to knock a fly off of a matchstick..

But...WILL they extinguish ignited flatulence? Summa' 'dem flies gots sticky little legs!


Yeah. Fan on a KDX lighting coil? Forget it.