HELP diagnosing problem.

[Bane]

I took my 8e out today to test with a brand new Nano-Tech 4s 65-130c 5000mAh, gearing is 15/45. Everything was fine for a few minutes and then suddenly it wasn't hitting top speed any more, the motor was very very hot to touch so I'm thinking perhaps that could be the problem and it needs replacing? Temps are as follows:

 

After 3 minutes:

 

Motor - 42.6*c

Battery - 34.4*c

ESC - 32.4*c

 

After another 2 minutes:

 

Motor - 70*c

Battery - 36.6*c

Esc - 38*c

 

I didn't run it for the entire battery pack obviously as something was wrong and the motor was too hot for my liking.

[MAZ]

Has it been fine before today? Could something be binding? All the diffs okay? Missing grubscrew in the centre driveshafts, maybe making the motor work harder and not getting the buggy to full throttle and causing it to get really hot?

[covert]

One thing you dont mention is kv and amp range of esc matey

[Bane]

Has it been fine before today? Could something be binding? All the diffs okay? Missing grubscrew in the centre driveshafts, maybe making the motor work harder and not getting the buggy to full throttle and causing it to get really hot?

 

The previous time I took it out was with a LiPo that was bad so I assumed the LiPo was the reason the motor was acting up that time. I recently built the centre diff, I will take a look at the rear and order some new gears and diff oil to rebuild that anyway. There is no binding from what I can see or any missing grubscrews. It did get very hot before when the gearing was 12/50 so could that possibly have damaged the motor from then?

One thing you dont mention is kv and amp range of esc matey

 ESC is a Xerun 150a and motor is the Turnigy Trackstar 2350kv.

[Noj]

Over gearing perhaps? Having ruled out binding issues of course.

Gear down and try again.

[Bane]

Over gearing perhaps? Having ruled out binding issues of course.

Gear down and try again.

 

People have said stock gearing for the 8e is 15/45 which I have so not sure if that can be an issue here.

[Tug]

The numbers suggest under-geared as the ESC and cells aren't hot. Try different ratios, but check temps every few mins.

[Bane]

The numbers suggest under-geared as the ESC and cells aren't hot. Try different ratios, but check temps every few mins.

 

Do I need a bigger or smaller pinion or spur gear? 

[Tug]

Bigger pinion will up the gearing, just watch temps closely.

[Bane]

Got some more temp readings today using a 17t pinion and the same 45t spur gear.

 

3 Minutes:

 

Motor - 51.4*c

Battery - 26.6*c

ESC - 29.6*c

 

6 minutes:

 

Motor - 63.2*c

Battery - 30.4*c

ESC - 43*c (I noticed the ESC fan stopped hence the increase in temp)

 

10 minutes:

 

Motor - 73*c

Battery - 35*c

ESC - 31*c (fan working)

 

 

What size pinion should I try now?

 

Also can someone tell me what temps I should be aiming for the motor, battery and ESC after a full pack?

 

Another thing I noticed was that near the end when the throttle was fully pressed the ESC's green light would stay solid, after checking the ESC manual it could possibly mean over heat protection but in the manual it states the green light should be flashing for that so kind of puzzled here.

Edited September 10, 2013 by Bane

[NuttyProfessor]

Full throttle is green, red should be reverse and brakes.

[big turbo]

I would gear up some more if you have the pinion's as the temps are balancing out and motor temps are not as high.I would try a 19t and check temps regularly.

160-170F for the motor

140F for the esc

100-110F for lipos

Solid green light is showing full throtle.

Edited September 10, 2013 by big turbo

[Bane]

Thanks for clearing up the green light thing, worried me there for a sec. I'll order a 19t pinion tonight. Silly question I know but what does the ESC protect with the over heat protection mode, is it the ESC itself, battery or motor?

[big turbo]

The esc itself.

[Bane]

So after 7 months I took the Losi back out again but this time with a 19t pinion and the spur is still the 45t stock one. The results once again weren't pleasing.

 

3 Minutes:

 

Motor - 49*c

Battery - 29*c

ESC - 38*c

 

6 minutes:

 

Motor - 74*c

Battery - 36*c

ESC - 54*c

 

Any suggestions? I rounded the temperature to the nearest whole number in case anyone is wondering lol.

[Tug]

Try a 16? Sounds over-geared to me. The higher you're gearing it, the hotter the motor is getting, so you need to go the other way. Bear in mind, some motors will always run hot.

[Noj]

Reminds me of when I converted the Losi 5ive to the MGM, up and down with gearing, as I was getting similar, 'strange' temp readings....

Appreciate it must be really frustrating now...perhaps order a few pinions, in sizes you haven't tried...least you can do quick changes until you have found the best one?

[big turbo]

I agree I does sound like it's over geared now hence why motor temps and esc temps are both higher now and as tug said some motors do just run hotter.

What the esc setting like ie drag brake force, motor timing and punch?

[brit_bulldog]

I think you should look at esc settings. Too much timing advance and turbo etc can cause your motor to get too hot!

[Bane]

I've ordered a 16t pinion and jotted down the ESC settings for you guys:

 

1. Forward/Reverse/Brake

2. Drag Brake 0%

3. Voltage Protection 3.4v/cell

4. DRRS Punch Level 5

5. Brake Force 75%

6. Reverse Force 25%

7. Initial Brake 0%

8. Neutral Range 9%

9. AMTS Timing 4

 

Thanks.

[Tug]

Those settings are fine, so it's either a smaller pinion for your chosen voltage or a different motor. I'd look at fitting a better quality motor, the HW motors are good value, or go the whole hog and get a Castle. Aim for 1800kv to a max of 2200kv.

[NuttyProfessor]

Or get a Leopard motor?

[big turbo]

http://www.msuk-forum.co.uk/topic/192111-sirius-1515-2200kv-motor/?view=getnewpost

[Tug]

As above, good choice!

[Bane]

Just got in from testing with the 16t pinion.

 

After 3 minutes:

 

Motor - 41*c

Battery - 26.2*c

ESC - 35.5*c

 

After 6 minutes:

 

Motor - 52*c

Battery - 27*c

Esc - 38*c

 

After 10 minutes:

 

Motor - 67*c

Battery - 29*c

Esc - 42.5*c

 

After 15 minutes:

 

Motor - 81*c

Battery - 39*c

ESC - 47*c

 

After the 15 minute mark I believe the reason for the battery and motor jumping up in temps that much was due to me not realising the battery was spent and carried on for another 30 seconds to 1 minute.