Medusa Afterburner V2 BL motors - Page 32 - RC-Monster Forums

FG101C · 08:22 PM

I'm trying to figure out the gearing for my D8 buggy. I'm using the 60mm 2000kv motor. On 4s I had it geared 15/48, the buggy uses truggy gearing in the diffs (43/10). It was good like that, 20 minutes run time but a little hot. Temps like that were right at 170-174. Could use a little more speed.

Today I wanted to try 5s. So I geared it 13/48, got a little hotter around 180. Next I tried a 16 tooth pinion, ran it about five minutes and checked it, temp ok. Ran another five minutes and it was right at 190. Ok so 16 is over geared, but is the 13 under geared? Or should I try 12, or go back to 15? Ordered the heatsink, but is that really going to make a difference? What would a 45 tooth spur do with 13 or 12 pinion or even the 15?

Batteries used are Polyquest 4s 6000mah and Hyperion 5s 4350 25c. ESC MMM v3. Batteries and ESC are running warm at best, it's just the motor getting hot.

I'm thinking I'm probably best off using the heatsink and the 4s 15/48 setup. Just wanted a little more top end.

Any suggestions are greatly appreciated.

suicideneil · 01.02.2009, 12:35 PM

If the motor is running hot its genrally a sign of undergearing as the motor is revving too much, but sometimes it can be caused by excessive over-gearing causing too much current draw due to the large load. I dunno what to say really, if you can gear it down even further and see what that does for the temps maybe. All this is assuming there isnt any outside issue like binding in the drivetrain or what not- take a look at your esc settings and lower the timging and start power if possible...

FG101C · 01.02.2009, 03:20 PM

Think in the morning I'll head up to the track. Try 12/48, 13/45, 15/45, 12/45. According to the calculator 12/45 would give me the little more top end I'm looking for.

JesseV · 09:10 PM

Was today on a track with my CEN Matrix bl with medusa 70mm 2300kv. 4s Zippy and 13/stock spur gearing. The motor is pretty great, got alot more torque than some china motor. Also I got nice 20min run and didnt even cut-off yet but was going slower so i stopped.

I had friend's datalogger on it, but dont have the diagrams yet, ill post them later. Anyways peak amps were below 100A and average current just below 10A which is very nice IMO. Peak power was 11xx W.

After the 20min run on track the motor was warm but not hot, even my battery was hotter.

sikeston34m · 01.04.2009, 11:56 AM

Quote:

Originally Posted by JesseV

Was today on a track with my CEN Matrix bl with medusa 70mm 2300kv. 4s Zippy and 13/stock spur gearing. The motor is pretty great, got alot more torque than some china motor. Also I got nice 20min run and didnt even cut-off yet but was going slower so i stopped.

I had friend's datalogger on it, but dont have the diagrams yet, ill post them later. Anyways peak amps were below 100A and average current just below 10A which is very nice IMO. Peak power was 11xx W.

After the 20min run on track the motor was warm but not hot, even my battery was hotter.

Great Graphs!

Was this using 4S 20C 5000mah Zippys?

JesseV · 01.04.2009, 12:30 PM

Quote:

Originally Posted by sikeston34m

Great Graphs!

Was this using 4S 20C 5000mah Zippys?

Thanks, yes. :) Imma buy 2 more Zippys since they seem to do just fine.

George16 · 01.02.2009, 09:14 PM

What's the timing set at on your ESC?

suicideneil · 01.02.2009, 09:18 PM

I would say define hot, but given the great numbers I doubt its anything to worry about much. If you havent got one already, pick up a cheap IR temp gun to see how your set up does after a run- no higher than 180*F for the motor, and ~120-130*F for the lipos.

JesseV · 01.02.2009, 09:24 PM

Quote:

Originally Posted by George16

What's the timing set at on your ESC?

I'll check tomorrow, but it was low. Also some punch control if i remember right.

Quote:

Originally Posted by suicideneil

I would say define hot, but given the great numbers I doubt its anything to worry about much. If you havent got one already, pick up a cheap IR temp gun to see how your set up does after a run- no higher than 180*F for the motor, and ~120-130*F for the lipos.

Yeah I have IR temp gun that I of course left home when I went to the track. :\ I'd say no hotter than 35-40C, which would be 95-104F, talking about motor.

I have the tekno rc motor mount with a fan on it. Outside theres no need for then fan since there's -11C (12F).

But on the track its good to have.

JesseV · 01.03.2009, 01:49 PM

Configs on MMM:

Data:

suicideneil · 01.03.2009, 02:34 PM

Sweet figures there- lipos hold their voltage very well under load.

Only thing I might suggest changing on the MMM is the throttle setting- put it to forwards-brake-reverse/lockout. I didnt like it when the truck would slow down then suddenly go into reverse automatically...

FG101C · 01.04.2009, 03:22 AM

I can't seem to get the 60mm 2000kv to run cool on 5s (pushing 190+), but on 4s, geared 15/50 the buggy rocks. Still a bit warmer than I like, 170 ish, but my timing is at Low (5), will set it to Lowest (0) and try again. 100% punch control, lowest start power setting, some curve in the throttle.

suicideneil · 01.04.2009, 02:26 PM

Quote:

Originally Posted by FG101C

I can't seem to get the 60mm 2000kv to run cool on 5s (pushing 190+), but on 4s, geared 15/50 the buggy rocks. Still a bit warmer than I like, 170 ish, but my timing is at Low (5), will set it to Lowest (0) and try again. 100% punch control, lowest start power setting, some curve in the throttle.

More than likely just too much voltage for that kv rating- 4 pole motors prefer (in principle, or my head atleast...) to be revved lower & geared taller to make your speed and power really. I think you'd be better of using 4s lipo and gear higher, or choose a lower kv motor (~1800kv region) for use with 5s to reduce current draw.

FG101C · 01.04.2009, 03:31 PM

Quote:

Originally Posted by suicideneil

More than likely just too much voltage for that kv rating- 4 pole motors prefer (in principle, or my head atleast...) to be revved lower & geared taller to make your speed and power really. I think you'd be better of using 4s lipo and gear higher, or choose a lower kv motor (~1800kv region) for use with 5s to reduce current draw.

Yes, I agree. I thought I learned alot about kv and voltage. But after even more digging I learned even more.

So for my Hyper ST build on 5s I will select my kv carefully. Really wish the medusa's came in 1700kv.

sikeston34m · 07:59 PM

Quote:

Originally Posted by FG101C

I can't seem to get the 60mm 2000kv to run cool on 5s (pushing 190+), but on 4s, geared 15/50 the buggy rocks. Still a bit warmer than I like, 170 ish, but my timing is at Low (5), will set it to Lowest (0) and try again. 100% punch control, lowest start power setting, some curve in the throttle.

Every good motor that's pushing some power is going to give off some heat.

For example:

Let's take 1000 watt motor that's 90% efficient. This means that all the time it's at the 1000 watt level (WOT) it's going to "bleed off" 100 watts of heat.

Running a smooth can motor with no heat sinking doesn't leave that heat much place to go. So, it builds up.

I've been having great success with the 36-60-2000kv in an E Revo gearing 18/52.

I'm using the Novak Heat Sink with it on 4S. I really believe I could run this all day long with no heat issues at all.

50 degrees outside and I can barely detect any heat at all coming from the motor.

If you have room, give it a try.

I do intend to try this on 5S AND on 6S. This will be the real test!