Kraton Can you run factory k8s fans off a separate 2s or 3s battery?

[shelbyslobra]

Just ran my k8s for the first time and liked it, however I want to change the pinion to a 23t. I’m pretty sure the factory fans won’t push enough air to keep it cool during a good run. So I was wondering if I could run the stock fans of off a 2s or 3s battery. I’ve tried to look up too see if they are 12v capable, and too see if anyone has done it but came up short. Any suggestions? Thanks.

 

[SrC]

A 2S vs 3S separate lipo would be best but is only 7.4v.
8.4v is the max BEC setting for the 160amp ESC. for the stock fan.
A 3S lipo(11.1v) may be pushing that stock fan too hard and fry it.
Default BEC is 6.0v. If you up the ESC BEC setting to 8.4v, your stock fan would run best. Just Power it off of 8.4v BEC.
Maybe others will have their ideas on this. More familiar with the 160amp Firma.

 

[shelbyslobra]

A 2S vs 3S separate lipo would be best but is only 7.4v.
8.4v is the max BEC setting for the 160amp ESC. for the stock fan.
A 3S lipo(11.1v) may be pushing that stock fan too hard and fry it.
Default BEC is 6.0v. If you up the ESC BEC setting to 8.4v, your stock fan would run best. Just Power it off of 8.4v BEC.
Maybe others will have their ideas on this. More familiar with the 160amp Firma.

I thought about that too. But With changing the esc bec to 8.4 I’m just worried about burning up the servo. Do you think it will be fine?

 

[SrC]

If using the stock servo, the servo manual specs show:
Torque 6v is 537.72 @ 7.2v is 555.50. (S905)
They don't say 8.4v BEC is applicable to this Servo. Considered a lame servo at that. FWIW. It has minimal torque and very slow for many.
Many guys are upgrading to the Primal Raminator servo as an upgrade. ( a true 1/5 scale servo). Just need the Arrma optional RX box that accepts legit 1/5 scale longer servos.
But not to get off the subject, your stock servo cant handle the 8.4v BEC according to its published specs.
Just strange that the 160 Firma offers 8.4v BEC but the servo can only use the default 6.0v ESC BEC setting. There is no 7.2v BEC setting.
Have guys done this? IDK.
To answer your question, probably a 2s Lipo power source for your Motor fan may be your best option. How significant it makes your motor run cooler is not clear. Using a better 12v 40x28+mm upgrade fan on the motor with a separate 3S lipo is one work around for sure. Better cooling if that is what you want.

Edit: have you checked your ESC settings to confirm what BEC volts are actually available? I got this info from the Spektrum 'Retail' Firma 160 amp ESC manual.

 

[K-BASH]

I run small 2s hump-pack on speedrun truck.

 

[Sloclone100]

56

I run small 2s hump-pack on speedrun truck.

View attachment 127224

That idea seems best to me. You could even use (I do), a 6 volt 2000mAh nMh battery, provided you can charge it. If not, a small LiPo like shown above will leave you worry free. I have two servos and three fans. And R/C fans are 5 volt. At least I have never seen one made for 12 volts, except computer stuff, which is way too big anyway.

Good luck to the OP. -Dave