Fans slowing.

[Woodentop]

Something I've never noticed before. The fans on my rigs slow significantly as the pack runs down. Towards the end I could blow more air with a fart. It happens on most of my rigs, the ones I've noticed recently anyway. Most are max 6/ 2 40mm fans of the reciever. Too much amp draw?. I've tried the 40 x 28 with a stubby pack and it was a faff, pack moving all the time etc. Same for everyone else's fans??.

 

[gotnitro]

Fans don't pull amps. That is simply a voltage drop = RPM drop.

 

[Woodentop]

Fans don't pull amps. That is simply a voltage drop = RPM drop.

Ah, gotcha. Completely normal then. Nothing I can do to keep a good rpm to the end of the pack??

 

[gotnitro]

Ah, gotcha. Completely normal then. Nothing I can do to keep a good rpm to the end of the pack??

IMO fans don't work anyway, keeping ESC and motor temps in check is all a balancing game and comes from your gearing and driving style in different ambient temperatures. Every single day and every gear tooth all depend on ambient temps, and you're throttle finger.

 

[SirCrashALot]

IMO fans don't work anyway, keeping ESC and motor temps in check is all a balancing game and comes from your gearing and driving style in different ambient temperatures. Every single day and every gear tooth all depend on ambient temps, and you're throttle finger.

I don't agree. Fans do work. They do cool the motor and esc. But they can never keep up delivering sufficient cooling when people go WOT all the time.

 

[gotnitro]

I don't agree. Fans do work. They do cool the motor and esc. But they can never keep up delivering sufficient cooling when people go WOT all the time.

Thats the beautiful part! You don't have to agree.

My personal experience comes from racing them almost at full throttle 80% of the time till the pack is gone. We never used fans on motors.

Peeps start adding all these fans, side batts to run them, all that wiring comes at a price for your hip and the performance of your now heavier car.

You might also find that running a fan is actually giving you false readings as its only probing the outside of the motor can while your internal parts are roasting away.

GL bruh..

 

[jkflow]

How are you powering the fans and what is their voltage rating?
Powered via receiver? There shouldn't be any voltage drop as they are regulated by your ESC output port. If that voltage is sagging you have some issues.

 

[SirCrashALot]

Thats the beautiful part! You don't have to agree.

My personal experience comes from racing them almost at full throttle 80% of the time till the pack is gone. We never used fans on motors.

Peeps start adding all these fans, side batts to run them, all that wiring comes at a price for your hip and the performance of your now heavier car.

You might also find that running a fan is actually giving you false readings as its only probing the outside of the motor can while your internal parts are roasting away.

GL bruh..

That's what i said. At full WOT the motor produces much more heat than any fan can deliver cool air. So fans are useless on pure racing rigs. But during bashing i hardly ever go full WOT and the fans get time to cool the system a bit.

 

[Boggs3010]

That's what i said. At full WOT the motor produces much more heat than any fan can deliver cool air. So fans are useless on pure racing rigs. But during bashing i hardly ever go full WOT and the fans get time to cool the system a bit.

That's why I bring 2 or 3 cars when bashing. Like yesterday my first day of the year!! Brought 2 new cars had some fun let one cool down run for 5/10 minutes and switch.

 

[Woodentop]

Powered via receiver? There shouldn't be any voltage drop as they are regulated by your ESC output port. If that voltage is sagging you have some issues.

So I'm just trying to understand this. Voltage sagging, is that my battery then? (Yoowoo graphene 6 cell pack) what other issues could be causing this? My connections look OK, the pack isn't particularly hot at lvc. The motor and esc aren't too hot either. Although I bash at wot a lot, I gear conservativly. As I say this happens on most of my rigs so battery would be the most logical thing. Obviously the fans are cooling nothing towards the end of the pack.

 

[Johnny b]

As hot as it gets down here in Florida, I'm still using my stock fans and never had motors shut down. I do like your cost effective method of farting on them and may resort to that if needed.

 

[gotnitro]

That's what i said. At full WOT the motor produces much more heat than any fan can deliver cool air. So fans are useless on pure racing rigs. But during bashing i hardly ever go full WOT and the fans get time to cool the system a bit.

Point being that if fans are useless on a race rig (I agree) because I'm at full throttle 80% of the time, how are they warranted on a basher where you are NOT at 80% WOT for the full pack. Total RC eye candy IMO.