servo glitch with fan and 7.2v servo
 

hi
just tried fitting a fan into my xx4. i run a ko2123 7.2v servo and quantum 2 esc with spektrum. when i plug the fan into the rx'er the servo glitches constantly unplug it and everything's fine. never had any glitching before i fitted the fan.
just wondered if anyone else has had a problem with 7.2v servo's and fan's

Yes I did have probs when I first tried this, in my opinion 7.2V the fan, it moves about twice as much air I reckon, miles more effective. Massive performance gain over minimal loss in fan life and no radio probs.

it is a 7.2 volt fan

he means wire it to your battery ie 7.2 volts instead of plug it in ur reciever

just tried that and it works fine, just didnt want to wire it that way, wanted it so when car is turned off the fan is off instead of having to unplug cells all the time.

cheers anyway at least i can use it now :)

you beat me to it! you knew!

Chris, it has it's advantages, once you've raced, leave your car plugged in and it will be completely cool by the time you've finished marshalling.

or possibly shag your 4200's if they go dead flat and reverse polarity :D

cheers for the help guy's

Chris, I once measured the fan and it takes like 0.02A or something, literally fcuk all, if your car isn't flat when you turn it off, the fan isn't going to kill them!

just means my car will now sound like sleigh's jet turbine xx4:D

if u were desperate you could solder 1 end to a battery connection and the other to a motor connection, this way u still get full power all the time and constant 7.2 volts and it will turn off when u turn the esc off, also another option is connecting it across the motor, but then the speed of the fan will change depending on the speed of the motor (throttle position)

I was going to suggest that mr simpson:)

Don't most receivers only put out about 5v anyway?

just tried that andrew, power to fan is constant

SHouldn't that depend on which way round, switching is done on negative I believe

Yeah, if you just go straight across the motor wires that should be ok

correct me if im wrong but do you mean connect the pos wire from the fan to the pos battery and neg fan wire to negative motor ?

In My Opinion...............

If you wire directly across the motor it will rev with the motor, however I think it's a bad idea. This is because 1 the spin up time of these fans is not great so will never perform very well, 2 being fed at high frequency from the speedo can't be good for it and 3 and reverse voltage spikes from when you break might pop it as well I would have thought.

What I was on about was that as the negative is switched whatever speedo (brushed) you have the positive is always live so motor positive to battery negative is constant live feed.

I'm happy to be wrong though ;)

doing it that way dan give's it a constant power feed even when esc switched off?!?!?!?.
ive tried it in several way's and can't seem to find a way to have it switched off when esc is off.

wire a 2nd switch to the fan system?