Cooling fan hookup?

[BrianG]

Originally Posted by cabking

I run a couple of 12v pc fans straight from the main cells.
at 22v they do spin some :030: never last too long though :027:

Put those two fans in series instead. Assuming they are rated the same current/voltage, each will get 11v and will last longer.

Using a resistor is not really bad as long as it is used to control one fan and that fan draws .2A (200mA) or less. To find the resistor value, just subtract the fan voltage from the supply voltage, and then divide that by the fan current. To find the power rating for the resistor, simply square the current, multiply by the resistor value, then double the final value for safety. Usually a two or 5 watt resistor is fine.

If CH3 is being used, hooking them to the output of the BEC. or the output of the on/off switch would be the best choice IMO.

Originally Posted by BrianG

Put those two fans in series instead. Assuming they are rated the same current/voltage, each will get 11v and will last longer.

Now were's the fun in that?
thay last about 2 months..thats good enough for me :003:

[sluggie24]

I hooked it up to the BEC output wire and it seems to be ok.....although the speed control isn't hooked to the motor yet. Since this is the first time I powered up the system I noticed that the steering servo seems to pulse/twitch when no steering input is being given, even when the wheels are off the ground. I disconnected the fan and the twitch did not change. The shift servo does not do it. I have an Airtronics MX-3XS controller and reciever and an Airtronics ERG-VB high torque steering servo. Does anyone have any idea what this might be caused by? The BEC is all the way in the back of the truck as far away as possible. I tried moving it around with no affect. Radio interference maybe? I was inside by the entertainment center.

Is the antenna wire touching, or very close to any metal parts? If so you should try relocating it. Sometimes this can cause the twitching you described (I experienced this with my rustler). Usually, if you can just run it straight up through the body and not snake it around other components, it won't recieve any interference. Oh, is that a DIGITAL SERVO? I have a Futaba S9451 and it does twitch every so often, but, not enough to affect my control.