RCCrawler Forums

Evandiego · 08-26-2009, 12:34 AM

What brushed motor could I use that's safe on 3s lipo?

I've converted my Wheely King to a crawler and love it! The HPI 27T Saturn motor and esc were slapped into my old Tamiya 4wd TL01 buggy and took it for a rip on 6 cell nicds. Not bad.

So I thought well....how about a 3s lipo that I use on my WK? Awesome! After 5 mins of bashing, the motor was smoking a bit and was pretty hot. Probably not built for more than 8.4 volts. Stock esc was warm.

I've heard that Integy lathes could run on 12V no problem. What motor could I run that'll take 3s lipo?

Any input would be much appreciated.

constantmotion · 08-26-2009, 06:07 AM

Just about any motor can run on 11.1V. The question is whether you ESC can handle it?

Evandiego · 08-26-2009, 07:13 AM

Hmm...I think my esc is taking it well. HPI said it'll run 3s but is not recommended. Let's just say I'm willing to take the chance on burning out the $20 esc...gives me an excuse to by a CC sidewinder!

I was just thinking that certain brushed motors are rated for a max rpm...so whatever that max rpm is, I shouldn't exceed it based on X rpms/volt.

Say the max rpm for a certain motor is 40,000 and spins at 4,000 rpm/volt. The threshold would be 10 volts. By exceeding the max volts what could potentially happen to the motor?

Take a 45T crawler motor and a 27T both with the same max rpm. Pumping 3s into both motors. Since the 45T would have a lower rpm output than the 27T, I would assume the 45T generate less heat and not work the esc as hard....am I on the right track?

I hope I don't get flamed for this.

JohnRobHolmes · 08-26-2009, 07:17 AM

I have run 20t motors on 4s no problem. It boils down to your final geardown, vehicle weight, and quality of motor.

The 45t on 3s could run as hot as the 27t if you geared it for the same vehicle speed.

Evandiego · 08-26-2009, 08:02 AM

JR Holmes! Thanks for the reply...it's an honour coming from a celebrity rock crawler. Lol! I was just reading your "Wire Your Rig Like a Pro" article in RC Rock Crawler magazine. Great write up.

My Tamiya buggy is pretty light. It's a 4wd shaft but took out the shaft and am running it 2wd. I'm running a sealed can HPI 27T motor. Probably not the best for 3s. I guess I'll be shopping for a modified 27T or maybe I'll try a 35T and have it geared as low as possible so as not to draw too much amps.

Thanks for the tips!

JohnRobHolmes · 08-26-2009, 08:04 AM

lol, celebrity!

Basically you can just gear for the heat. If you can gear the 27t low enough it would work too.

Evandiego · 08-26-2009, 09:14 PM

Tried running it tonight. Saw a few sparks from the motor and turned for about 2 seconds and toast. Esc still works fine. Getting input from the radio but motor has had it. Eeek! Gonna go shopping for a new rebuildable one.

08-26-2009, 12:34 AM	#1
Evandiego Pebble Pounder Join Date: Jun 2009 Location: Canada Posts: 196	What brushed motor on 3s? What brushed motor could I use that's safe on 3s lipo? I've converted my Wheely King to a crawler and love it! The HPI 27T Saturn motor and esc were slapped into my old Tamiya 4wd TL01 buggy and took it for a rip on 6 cell nicds. Not bad. So I thought well....how about a 3s lipo that I use on my WK? Awesome! After 5 mins of bashing, the motor was smoking a bit and was pretty hot. Probably not built for more than 8.4 volts. Stock esc was warm. I've heard that Integy lathes could run on 12V no problem. What motor could I run that'll take 3s lipo? Any input would be much appreciated.

08-26-2009, 06:07 AM	#2
constantmotion On the lookout for Rocks Join Date: Mar 2006 Location: Monroe, Louisiana Posts: 3,711	Just about any motor can run on 11.1V. The question is whether you ESC can handle it?

08-26-2009, 07:13 AM	#3
Evandiego Pebble Pounder Join Date: Jun 2009 Location: Canada Posts: 196	Hmm...I think my esc is taking it well. HPI said it'll run 3s but is not recommended. Let's just say I'm willing to take the chance on burning out the $20 esc...gives me an excuse to by a CC sidewinder! I was just thinking that certain brushed motors are rated for a max rpm...so whatever that max rpm is, I shouldn't exceed it based on X rpms/volt. Say the max rpm for a certain motor is 40,000 and spins at 4,000 rpm/volt. The threshold would be 10 volts. By exceeding the max volts what could potentially happen to the motor? Take a 45T crawler motor and a 27T both with the same max rpm. Pumping 3s into both motors. Since the 45T would have a lower rpm output than the 27T, I would assume the 45T generate less heat and not work the esc as hard....am I on the right track? I hope I don't get flamed for this.

08-26-2009, 07:17 AM	#4
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	I have run 20t motors on 4s no problem. It boils down to your final geardown, vehicle weight, and quality of motor. The 45t on 3s could run as hot as the 27t if you geared it for the same vehicle speed.

08-26-2009, 08:02 AM	#5
Evandiego Pebble Pounder Join Date: Jun 2009 Location: Canada Posts: 196	JR Holmes! Thanks for the reply...it's an honour coming from a celebrity rock crawler. Lol! I was just reading your "Wire Your Rig Like a Pro" article in RC Rock Crawler magazine. Great write up. My Tamiya buggy is pretty light. It's a 4wd shaft but took out the shaft and am running it 2wd. I'm running a sealed can HPI 27T motor. Probably not the best for 3s. I guess I'll be shopping for a modified 27T or maybe I'll try a 35T and have it geared as low as possible so as not to draw too much amps. Thanks for the tips!

08-26-2009, 08:04 AM	#6
JohnRobHolmes owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down! Posts: 20,290	lol, celebrity! Basically you can just gear for the heat. If you can gear the 27t low enough it would work too.

08-26-2009, 09:14 PM	#7
Evandiego Pebble Pounder Join Date: Jun 2009 Location: Canada Posts: 196	Tried running it tonight. Saw a few sparks from the motor and turned for about 2 seconds and toast. Esc still works fine. Getting input from the radio but motor has had it. Eeek! Gonna go shopping for a new rebuildable one.

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