Fitting a Cooling Fan on the Motor - Skeeter

[MouthbreatherRC]

I got into a bit of a pickle this wet Saturday afternoon, after deciding to fit that cheap fan I bought on Temu.

After taking the receiver out of its box, with the car switched off, I plugged it into channel three. I was so pleased when I switched the car on and the fan started to work.

This moment of triumph was soon forgotten when the realisation that nothing else would work became apparent. No signal LED on the receiver, no throttle and/or steering.

After trying a number of unsuccessful engineer resets (switch on/switch off). In despair I unplugged the new fan and attempted to bind the transmitter to the receiver. I got this to eventually work, by trying a number of different on/off, push the bind button combinations until the little LED started flashing to show pairing mode. In typical foolhardy fashion, I plugged the fan back in only to have to repeat the whole frustrating process again. Fan now set aside!

My question is, is there a reason that the fan caused this receiver fault to occur. It seems it must of been the culprit?

Also, would I be better off buying a splitter cable and plugging it into the ESC, where a fan is already connected. I have added some picture below for clarity.

It must be possible to add a fan, as Corally have helpfully created a ’blank’ position for one by the motor.

Thanks in advance for any help/advice.

 

[Klappars]

Could you confirm the orientation you plugged the fan connector in?

It should be with the gold contacts facing towards the top of the receiver and using the far right 2 pins.

 

[MouthbreatherRC]

Could you confirm the orientation you plugged the fan connector in?

It should be with the gold contacts facing towards the top of the receiver and using the far right 2 pins.

Hi, and thank you for the reply.

I can’t remember off-hand, but I will try again. By top of the receiver, do you mean where they red LED is positioned and the writing on it is orientated to read properly?

Would plugging it in incorrectly upset the reciever?\

Thanks again

 

[Klappars]

Hi, and thank you for the reply.

I can’t remember off-hand, but I will try again. By top of the receiver, do you mean where they red LED is positioned and the writing on it is orientated to read properly?

Would plugging it in incorrectly upset the reciever?\

Thanks again

Yes, with the red LED at the top. Plugging the fan in the wrong polarity shouldn't break anything, it's just the fan wouldn't work.

In this case, it could be that the fan is faulty and has electrically shorted out, which when plugged into the receiver would cause a current over-load and the ESC would shut down due to this to protect itself.

 

[MouthbreatherRC]

Yes, with the red LED at the top. Plugging the fan in the wrong polarity shouldn't break anything, it's just the fan wouldn't work.

In this case, it could be that the fan is faulty and has electrically shorted out, which when plugged into the receiver would cause a current over-load and the ESC would shut down due to this to protect itself.

Thank you for the quick reply.

it was a cheap fan, and I think I will dump it and keep the heatsink it was attached to and buy something with a bit more quality.

I have seen some on the Corally website, but I will need to work out what I need. I don’t want to ‘brick’ the receiver. Sorry for another question, but would you know what voltage it should draw?

 

[Klappars]

Thank you for the quick reply.

it was a cheap fan, and I think I will dump it and keep the heatsink it was attached to and buy something with a bit more quality.

I have seen some on the Corally website, but I will need to work out what I need. I don’t want to ‘brick’ the receiver. Sorry for another question, but would you know what voltage it should draw?

Probably a good plan. I would suggest a Centro fan or similar, depends what you can buy in your area.

The voltage for most standard fans is around 5-6v where what high speed fans are 7.4-8.4v.


That’s just the voltage they will accept, the current draw is also relevant which in the case of high speed fans is usually around 0.5-0.8amps

The current draw is really only relevant in relation the the BEC output of the ESC, which is what’s powering the receiver, servo and fans.

 

[MouthbreatherRC]

Probably a good plan. I would suggest a Centro fan or similar, depends what you can buy in your area.

The voltage for most standard fans is around 5-6v where what high speed fans are 7.4-8.4v.


That’s just the voltage they will accept, the current draw is also relevant which in the case of high speed fans is usually around 0.5-0.8amps

The current draw is really only relevant in relation the the BEC output of the ESC, which is what’s powering the receiver, servo and fans.

Thanks for the helpful response.

The Centro product is available in the UK from Modelsport who also sell this Corally branded one.

They are both 30mm and will fit in purpose made space behind the motor.

Googled BEC Output and see that is related to regulating voltage. Lot to learn with this hobby.

Thanks again for your help

 

[ThaChester]

Thanks for the helpful response.

The Centro product is available in the UK from Modelsport who also sell this Corally branded one.

They are both 30mm and will fit in purpose made space behind the motor.

Googled BEC Output and see that is related to regulating voltage. Lot to learn with this hobby.

Thanks again for your help

BEC provides power to anything that needs power but isn't connected to the batteries (i.e receiver, servo's, lights). Each ESC has a max amperage that it can provide. Say it's 6 amps. Anything that is running off the BEC circuit will draw a certain amount of amps. So say you have 3 fans that draw 0.8 amps, a servo that can draw up to 2.3 amps, lights that draw 0.5 amps. You have to total all your possible amp draw and keep it under what your ESC is capable of by either lowering the items using the BEC circuit by say directly connecting the lights to your battery or using an seperate power battery.

Also in the picture of your ESC showing the fan plug it does appear to be you had it correctly plugged in. If you look in the picture I attached you can see they label which wires go where. Black to ground(-), red to positive(+).

 

[Klappars]

Thanks for the helpful response.

The Centro product is available in the UK from Modelsport who also sell this Corally branded one.

They are both 30mm and will fit in purpose made space behind the motor.

Googled BEC Output and see that is related to regulating voltage. Lot to learn with this hobby.

Thanks again for your help

I can recommend Modelsport, assuming you are in the UK?

Here is the setup I have on my Asuga, it’s a Yeah Racing dual fan heatsink with 2mm PC thermal pads to improve heat conductivity and a Centro 30mm fan.

The BEC (battery elimator circuit) is a separate power line from the ESC which powers the receiver and anything connected to the receiver via the CH2 input.

 

[MouthbreatherRC]

BEC provides power to anything that needs power but isn't connected to the batteries (i.e receiver, servo's, lights). Each ESC has a max amperage that it can provide. Say it's 6 amps. Anything that is running off the BEC circuit will draw a certain amount of amps. So say you have 3 fans that draw 0.8 amps, a servo that can draw up to 2.3 amps, lights that draw 0.5 amps. You have to total all your possible amp draw and keep it under what your ESC is capable of by either lowering the items using the BEC circuit by say directly connecting the lights to your battery or using an seperate power battery.

Also in the picture of your ESC showing the fan plug it does appear to be you had it correctly plugged in. If you look in the picture I attached you can see they label which wires go where. Black to ground(-), red to positive(+).

View attachment 4745

Hi,

Thank you for your reply and help.

Your explanation of the BEC is very useful, and helps me to understand this further. Years ago I had a Schumacher Nitro 10 and I remember it having a small carrier with 4 x AA’s in it, which I guess ran the servo and receiver.

Things seem to have really advanced in the intervening 20+ years!

Thanks also for the image insert. I hadn’t actually plugged the fan into the ESC, but into the receiver. The ESC on the Sketer comes with. fan attached. I had thought of plugging the extra (motor) fan into this ‘outlet’ to see if it works, but I think it’s supposed to be on Channel 3 of the receiver?

I can recommend Modelsport, assuming you are in the UK?

Here is the setup I have on my Asuga, it’s a Yeah Racing dual fan heatsink with 2mm PC thermal pads to improve heat conductivity and a Centro 30mm fan.

The BEC (battery elimator circuit) is a separate power line from the ESC which powers the receiver and anything connected to the receiver via the CH2 input.
View attachment 4746

Thanks for the extra info.

That is a nice set-up and the parts on Modelsport are very reasonably priced.

I want to get a fan on the motor, as I want to try some bigger wheels on the Sketer to see if it helps reduce the nose-diving (I have read bigger wheels might cause overheating). I took it to a skatepark today and bent the rear shock tower as a result of this issue, although I think to much skatepark bashing will equate to big money in parts anyway

 

[Horatio]

Surpass hobby finned twin fan mount and carbon fibre fan plates, fitted with countersunk washers.

The fan wires are plugged into a spare channel of the Rx with a Y lead. No need to plug them into ESC then.

 

[ThaChester]

Hi,

Thank you for your reply and help.

Your explanation of the BEC is very useful, and helps me to understand this further. Years ago I had a Schumacher Nitro 10 and I remember it having a small carrier with 4 x AA’s in it, which I guess ran the servo and receiver.

Things seem to have really advanced in the intervening 20+ years!

Thanks also for the image insert. I hadn’t actually plugged the fan into the ESC, but into the receiver. The ESC on the Sketer comes with. fan attached. I had thought of plugging the extra (motor) fan into this ‘outlet’ to see if it works, but I think it’s supposed to be on Channel 3 of the receiver?

All nitro's use those small packs to power servo's and receivers. With electric trucks since you have a battery already it makes sense not to have 2. So the ESC has the BEC. It elimnates the smaller battery. Plugging the fans into the ESC or the receiver do the same thing. The ESC has the port for your ESC fan just to cut down on wiring. You can plug the fans into any unused channel on the receiver. There's 3 pins per channel. 1 for positive power, 1 for ground(negative), 1 for handling the communication for the servo. You'll notice your fans most likely only have 2 wires. 1 is positve, 1 is ground. There's no need for a communication circuit for the fans. So plugging in the fan the wrong way won't harm anything it just wont work. When plugging in anything to the receiver look at the other channels that are already connected note the orientation of the red, black, white wires and plug your fan in the same orientation. You'll just be lining up the red and black wires as the fan won't have the third wire.

I want to get a fan on the motor, as I want to try some bigger wheels on the Sketer to see if it helps reduce the nose-diving (I have read bigger wheels might cause overheating). I took it to a skatepark today and bent the rear shock tower as a result of this issue, although I think to much skatepark bashing will equate to big money in parts anyway

2 things can effect temps with tires. one is weight and the big one is the diameter of the tire. Changing the size of the tire is doing the same thing as changing your pinion gear size. Going to a bigger tire is the same as going to a higher tooth count pinion. Going smaller in diameter is equivalnt to going down in pinion tooth count. So going to a larger tire will cause you to loose accelleration, gain top speed, lessening pulling power thus making the motor work harder. To counter act this you would use a lower tooth count pinion gear.

The best thing to do is monitor your temps. Then make changes based off that.

What is the issue with the nose-diving, I couldn't see where you mentioned that before? Do you mean nose diving while doing jumps and not being able to rotate the vehicle with the throttle or brake?

 

[Horatio]

For all the reasons posted above, I'd think twice about changing the diameter of tyres significantly, unless you are able to adjust your gearing accordingly. Changing the diameter of your tyres alters the rollout of your truck (mm/rev) which is directly associated with the gearing.

Nose diving on jumps can be due to numerous reasons, the main one being that the face of the ramp being to short for the size of the vehicle (as discussed previously on a different thread).

Assuming the ramp is big enough, it could also be because of:

• Rear spring rate too low (soft) causing the rear to bottom out on the ramp.
• Insufficient preload (causing the truck to run too low at the rear) and bottom out on the ramp.
• Too high a preload at the rear (causing the truck to sit higher at the rear) creating a tendancy to transfer weight to the front

Increasing the diameter of the tyres won't help with the balance of the car, although bigger tyres will give you more authority with controlling the attitude of the car in flight using the throttle. This is why some people prefer the fact that unbelted tyres turn into pizza cutters during big air.

 

[MouthbreatherRC]

All nitro's use those small packs to power servo's and receivers. With electric trucks since you have a battery already it makes sense not to have 2. So the ESC has the BEC. It elimnates the smaller battery. Plugging the fans into the ESC or the receiver do the same thing. The ESC has the port for your ESC fan just to cut down on wiring. You can plug the fans into any unused channel on the receiver. There's 3 pins per channel. 1 for positive power, 1 for ground(negative), 1 for handling the communication for the servo. You'll notice your fans most likely only have 2 wires. 1 is positve, 1 is ground. There's no need for a communication circuit for the fans. So plugging in the fan the wrong way won't harm anything it just wont work. When plugging in anything to the receiver look at the other channels that are already connected note the orientation of the red, black, white wires and plug your fan in the same orientation. You'll just be lining up the red and black wires as the fan won't have the third wire.


2 things can effect temps with tires. one is weight and the big one is the diameter of the tire. Changing the size of the tire is doing the same thing as changing your pinion gear size. Going to a bigger tire is the same as going to a higher tooth count pinion. Going smaller in diameter is equivalnt to going down in pinion tooth count. So going to a larger tire will cause you to loose accelleration, gain top speed, lessening pulling power thus making the motor work harder. To counter act this you would use a lower tooth count pinion gear.

The best thing to do is monitor your temps. Then make changes based off that.

What is the issue with the nose-diving, I couldn't see where you mentioned that before? Do you mean nose diving while doing jumps and not being able to rotate the vehicle with the throttle or brake?

Thanks for posting.

Those twin fans look very neat, and I guess provide masses of airflow over the motor. I have just bought a Y lead, but I don’t think I will need it for the installation I have planned.

All nitro's use those small packs to power servo's and receivers. With electric trucks since you have a battery already it makes sense not to have 2. So the ESC has the BEC. It elimnates the smaller battery. Plugging the fans into the ESC or the receiver do the same thing. The ESC has the port for your ESC fan just to cut down on wiring. You can plug the fans into any unused channel on the receiver. There's 3 pins per channel. 1 for positive power, 1 for ground(negative), 1 for handling the communication for the servo. You'll notice your fans most likely only have 2 wires. 1 is positve, 1 is ground. There's no need for a communication circuit for the fans. So plugging in the fan the wrong way won't harm anything it just wont work. When plugging in anything to the receiver look at the other channels that are already connected note the orientation of the red, black, white wires and plug your fan in the same orientation. You'll just be lining up the red and black wires as the fan won't have the third wire.


2 things can effect temps with tires. one is weight and the big one is the diameter of the tire. Changing the size of the tire is doing the same thing as changing your pinion gear size. Going to a bigger tire is the same as going to a higher tooth count pinion. Going smaller in diameter is equivalnt to going down in pinion tooth count. So going to a larger tire will cause you to loose accelleration, gain top speed, lessening pulling power thus making the motor work harder. To counter act this you would use a lower tooth count pinion gear.

The best thing to do is monitor your temps. Then make changes based off that.

What is the issue with the nose-diving, I couldn't see where you mentioned that before? Do you mean nose diving while doing jumps and not being able to rotate the vehicle with the throttle or brake?

Thank you, I appreciate all the detail in your reply.

I had been looking at the pinion gears, but thought that I could substitute changing it for what I thought would be the easier fan Installation.

I am still going to order a fan from Modelsport and maybe a pinion gear…. Do you know how many teeth the stock set-up has?

 

[Horatio]

Dual fans fitted on the finned mount now on the 4292 1780Kv motor.

Keeping motors cool simply isn't an option - it's a necessity.

Magnetic flux is lost if motors overheat.

 

[MouthbreatherRC]

For all the reasons posted above, I'd think twice about changing the diameter of tyres significantly, unless you are able to adjust your gearing accordingly. Changing the diameter of your tyres alters the rollout of your truck (mm/rev) which is directly associated with the gearing.

Nose diving on jumps can be due to numerous reasons, the main one being that the face of the ramp being to short for the size of the vehicle (as discussed previously on a different thread).

Assuming the ramp is big enough, it could also be because of:

• Rear spring rate too low (soft) causing the rear to bottom out on the ramp.
• Insufficient preload (causing the truck to run too low at the rear) and bottom out on the ramp.
• Too high a preload at the rear (causing the truck to sit higher at the rear) creating a tendancy to transfer weight to the front

Increasing the diameter of the tyres won't help with the balance of the car, although bigger tyres will give you more authority with controlling the attitude of the car in flight using the throttle. This is why some people prefer the fact that unbelted tyres turn into pizza cutters during big air.

Hi Again,

I hadn’t forgotten or dismissed your helpful advice in the other thread I had started. In fact I successfully put it into practice when I took the car to a beach and built a ramp from sand. Nonetheless my brothers MT10 pretty much landed four wheels down each time, and at the skateboard park the Sketer was dire! Of course it maybe that the myriad of YouTubers that I see jumping their cars only pick out the best bits of footage and get given the cars for free etc.

I won’t be doing anything regarding wheels soon as they seem quite expensive, so maybe just the fan first.

View attachment 4779
Dual fans fitted on the finned mount now on the 4292 1780Kv motor.

Keeping motors cool simply isn't an option - it's a necessity.

Magnetic flux is lost if motors overheat.

I know this first hand from problems with a non starting car and issues with a crankshaft position sensor.