Talion Not sure why I'm overheating

[Thumper33]

Ok ok, so the motor is a 1520-1650 castle. It ran fine when I was running on the street, but now that I've made an offroad track and am up to 65% max throttle it heats up pretty fast. I only get about 10 mins before it hits shutoff @ 170. I have the ESC limit motor temp to 180... Though in the logs it says max was 171... Ehhh whatever. The point is... I don't have a heat sink or fan on it. I only went w the 1520 over the 171 because it was 90 grams lighter. If I'm going to put 90 grams of heatsink and fan on it then I'd rather just buy a 1717 and keep fanless. I know the 1520 isn't popular on here but any guesses how much more time a heatsink alone might buy me? Also, it's only 60 degrees out, and I plan to run it in 90 degree weather. Soooo... Yeah...

Oh, I'm already @ a 15t pinion. Is it worth going down another tooth or two? I don't think top speed is going to be an issue if I do, but the only other pinion I have lying around is a 12t and I'm guessing that's too small. Guess it can't hurt to try.

 

[21STalion]

Sorry you are having difficulty but makes me glad I got the 1717

I bought an elaborate fan setup but turns out I never needed it. Never got the motor "hot", usually just warm. I have two kinds of infrared thermometers and the logs. 160 was about the highest I got with a 23t on 6s.

Next I'm trying 30t/44t on 100mm tires for a speed run.

 

[Thumper33]

Ya, I'm sure the sliding around hairpins w the throttle pinned is adding up heat fast. You think the 1717 can sheds that much more heat? I dropped from a 21 tooth to 15 tooth and it barely made a difference.

 

[LicketySplit]

Ok ok, so the motor is a 1520-1650 castle. It ran fine when I was running on the street, but now that I've made an offroad track and am up to 65% max throttle it heats up pretty fast. I only get about 10 mins before it hits shutoff @ 170. I have the ESC limit motor temp to 180... Though in the logs it says max was 171... Ehhh whatever. The point is... I don't have a heat sink or fan on it. I only went w the 1520 over the 171 because it was 90 grams lighter. If I'm going to put 90 grams of heatsink and fan on it then I'd rather just buy a 1717 and keep fanless. I know the 1520 isn't popular on here but any guesses how much more time a heatsink alone might buy me? Also, it's only 60 degrees out, and I plan to run it in 90 degree weather. Soooo... Yeah...

Oh, I'm already @ a 15t pinion. Is it worth going down another tooth or two? I don't think top speed is going to be an issue if I do, but the only other pinion I have lying around is a 12t and I'm guessing that's too small. Guess it can't hurt to try.

Running off road draws more current since there's more rolling resistance. I'd choose just the 1717 over fans. Main reason is running offroad sucks a lot of crap into the fan. I'll be replacing the stock motor in my Outcast 6s exb with a 1650 soon for this very reason. I'd rather not run a fan on an off road basher.

 

[Gdub34]

Z check your motor timing

 

[Kingleo619]

What spur you running?
You could Get a infraction 46t or 40t spur and gear up to 20-29t will also lower temps

I run 34/34 speedruns only on a 8s 1650 temps start to get warm after 15 minutes but i do run 2 12volt fans also

 

[3x9rtse]

Pull the pinion and make sure it rolls feely to check for locked up / seized bearings causing resistance .

 

[21STalion]

Sorry you are having difficulty but makes me glad I got the 1717

I bought an elaborate fan setup but turns out I never needed it. Never got the motor "hot", usually just warm. I have two kinds of infrared thermometers and the logs. 160 was about the highest I got with a 23t on 6s.

Next I'm trying 30t/44t on 100mm tires for a speed run.

I should mention that I'm usually running at temperatures just barely above freezing. So if your in a hot climate it may not apply

 

[Moirae]

Have you tried gearing up?

 

[Thumper33]

Have you tried gearing up?

I started with a 21, then went down to 15. Those are the only two I have. I've ordered a 13 and 11 and I'll see what that does. I'm also going to try to find a heat sink, but I'm not finding anything that's 41.6mm. Does it not have to be exact? I see some 42mm and some 40mm.

I checked the ESC logs and i'm maxing out at 54,000 rpm and motor max is 60,000. I'm not hitting 54k very often though. mostly was hitting about 40k on peaks. I do have a 23 pinion to throw in there if you want me to run it and see.

What spur you running? You could Get a infraction 46t or 40t spur and gear up to 20-29t will also lower temps

It's a stock spur... whatever that is.

check your motor timing

I just doublechecked my timing. It's set to 10 degrees which castle calls "normal". I'm going to drop it down to "low" (5 degrees) and see how much of a difference that makes.

I just spent some time looking at the logs. It took me 7.3 mins to get the motor to 171.5 degrees which was when it shut off. Looking at the slope of the line it's not like it was leveling out, and I'm just learning to drive this course. Another session or two and I should be able to keep more speed. Also, notice that the times when I'm just sitting idle (I rolled or flipped a couple times), the motor continues to heat up. It's clear to me that I need to get some air to this motor. The graph below is motor temp in red and rpms in brown.

edit:

Just noticed that I got a reply from Castle on their take. Here's their reply: " Drop the pinion down to 12T so it can generate more torque and reduce current draw. If you're limiting the speed to 60% that'll make it run hotter, and if you're not using the speed you're geared for it's better to reduce the gearing or even reduce the battery voltage so you can run it without limiting the throttle."

I understand that dropping the pinion down will make it run cooler, but how is limiting the speed to 60% making it run hotter? I kinda wonder if he misunderstood that I was talking about throttle limit, not speed limit. Oh well, as mentioned above, I'll try running a 12T pinion next time I run and see how that goes.

edited again: As far as what the motor sees, isn't having the throttle stop set at 50% on a 6s battery the same as running wide open on a 3s battery?

 

[SrC]

Get a good motor fan mount and fans. ( 2 x 40mm) Change to a larger or faster ESC fan. Skip the Motor HS altogether. Bring motor timing to zero( lowest it will go), if you can, if ESC so equipped. Drop your punch down. Evaluate temps each time. You might find that sweet spot. Seems you are hot n matter the pinion gear. Look over the Motor's BB's well. Clean and lube them. (Synthetic Oil) Consider replacing the BB's with Ceramics. They tend to run cooler for me.
I am anal about Motor maintenance.
Seems your electrics are not running efficiently enough somewhere.

 

[21STalion]

I started with a 21, then went down to 15. Those are the only two I have. I've ordered a 13 and 11 and I'll see what that does. I'm also going to try to find a heat sink, but I'm not finding anything that's 41.6mm. Does it not have to be exact? I see some 42mm and some 40mm.

I checked the ESC logs and i'm maxing out at 54,000 rpm and motor max is 60,000. I'm not hitting 54k very often though. mostly was hitting about 40k on peaks. I do have a 23 pinion to throw in there if you want me to run it and see.


It's a stock spur... whatever that is.


I just doublechecked my timing. It's set to 10 degrees which castle calls "normal". I'm going to drop it down to "low" (5 degrees) and see how much of a difference that makes.

I just spent some time looking at the logs. It took me 7.3 mins to get the motor to 171.5 degrees which was when it shut off. Looking at the slope of the line it's not like it was leveling out, and I'm just learning to drive this course. Another session or two and I should be able to keep more speed. Also, notice that the times when I'm just sitting idle (I rolled or flipped a couple times), the motor continues to heat up. It's clear to me that I need to get some air to this motor. The graph below is motor temp in red and rpms in brown.

View attachment 210279

edit:

Just noticed that I got a reply from Castle on their take. Here's their reply: " Drop the pinion down to 12T so it can generate more torque and reduce current draw. If you're limiting the speed to 60% that'll make it run hotter, and if you're not using the speed you're geared for it's better to reduce the gearing or even reduce the battery voltage so you can run it without limiting the throttle."

I understand that dropping the pinion down will make it run cooler, but how is limiting the speed to 60% making it run hotter? I kinda wonder if he misunderstood that I was talking about throttle limit, not speed limit. Oh well, as mentioned above, I'll try running a 12T pinion next time I run and see how that goes.

edited again: As far as what the motor sees, isn't having the throttle stop set at 50% on a 6s battery the same as running wide open on a 3s battery?

I'm surprised your having heat issues but it seems to build up slowly no? And it's only above 150f after like 20 minutes of racing?

That's not too bad ...

And no 3s is not the same as 6s. I'm not the expert but the amps generate more heat than the volts so running the same speed with more S will run cooler (since the same work will require less amps)

You should be running 5s (my idiotic suggestion)



Edit: 5s, 17t pinion, 140mm tire is my recommendation truck will be a monster out there

 

[Thumper33]

I'm surprised your having heat issues but it seems to build up slowly no? And it's only above 150f after like 20 minutes of racing?

That log is the 2nd or 3rd of a couple of runs. it goes from ambient to shut down in a little over 7 mins.

Good point about 3s vs 6s. I know electricity well, but didn't think about it from that perspective. Power is measured in watts. If you want to turn a motor, more wattage is faster. Wattage is current x voltage. If you want to push 1000 watts, you can get there by using 10 volts or 100 volts, but with 10 volts you need 100 amps of current. with 100 volts you only need 10 volts of current. Heat is proportional to the amount of current, so running a higher voltage should produce less heat. I suppose I didn't know if this 100% translated in brushless motors since that's not my expertise.

 

[21STalion]

Good point about 3s vs 6s. I know electricity well, but didn't think about it from that perspective. Power is measured in watts. If you want to turn a motor, more wattage is faster. Wattage is current x voltage. If you want to push 1000 watts, you can get there by using 10 volts or 100 volts, but with 10 volts you need 100 amps of current. with 100 volts you only need 10 volts of current. Heat is proportional to the amount of current, so running a higher voltage should produce less heat. I suppose I didn't know if this 100% translated in brushless motors since that's not my expertise.

You got it. It's the same here. One of my best friends is an electrician and we've been discussing it in length. It does apply here just like it does everywhere else. Use the highest voltage you can to keep amps low (and therefore temps apparently)

That said, I wouldn't expect you to overheat in 7 minutes with such a long can. I have 3 motors here. And as an example I'm using a 4268 2150kv buggy motor on my lightweight racing talion currently and even that doesn't have a fan on it. On our small, cold, track it's not over heating.

On my 1717 1650 can, I run at 3s and 4s on the track, I can drive back to back packs it never gets hot. All day - its only warm. Has so much bloody power I'm barely feathering the throttle around the track.

I always run at 100 power and basically have zero (or default) timing, No Cheats, and think I do like 25% punch (castle style programming)?

Wish I could toss your motor in my rigg for some testing.

I'm building a Kyosho Mp10e just this minute - came in the mail today




Here it is with the 4268

 

[Thumper33]

I was mulling the whole voltage thing over in my head and I have something to point out. Lets say we have a 3s and a 6s setup side by side. We are going to set the throttle stop of the 6s to 50%. It's my understanding that if we looked at the voltage waveforms coming from the esc, both would have approximately the same voltage at "full throttle" and no load. Now the question is: what happens when you put a high load on both of them. Does the esc know that there is a higher load and does it compensate increasing voltage to avoid slowing down? Does the motor just draw more current under load? Does one draw more current under load than the other? These are the questions I believe we need answered to really understand the effect of higher voltage batteries relative to heat.

edit: Oh, I forgot to comment on your pic. First off... SWEET Couple of questions... I'm assuming it does just fine in a tumble without the center brace? Also, with as much as you've modified on that rig, I'm surprised to see a completely in tact stock battery cage. FYI, you can save 13.6 grams by removing that slidey top thing. I'm also thinking about cutting away some of the plastic. Sure it's splitting hairs, but don't tell me you haven't spent far more to save less weight.

edit2: what's the tiny red electrical box on top of the steering plate?

 

[21STalion]

edit: Oh, I forgot to comment on your pic. First off... SWEET Couple of questions... I'm assuming it does just fine in a tumble without the center brace? Also, with as much as you've modified on that rig, I'm surprised to see a completely in tact stock battery cage. FYI, you can save 13.6 grams by removing that slidey top thing. I'm also thinking about cutting away some of the plastic. Sure it's splitting hairs, but don't tell me you haven't spent far more to save less weight.

edit2: what's the tiny red electrical box on top of the steering plate?

Does fine in a tumble. I haven't really broken anything since I started getting crazy light weight. Titanium helps too and is less obvious.

Interesting idea about the battery cage. There is a lot I can remove to still decrease even more weight, but it's a bit of a balance.

Still waiting for the rear cvds & v3 motor mount to take off another ounce and a half. I'll be well into the 6lbs range then

Red thing is a MyLaps Transponder for the racetrack to keep track of your laptimes. More necessary weight sacrifices

 

[SrC]

I'm surprised your having heat issues but it seems to build up slowly no? And it's only above 150f after like 20 minutes of racing?

That's not too bad ...

And no 3s is not the same as 6s. I'm not the expert but the amps generate more heat than the volts so running the same speed with more S will run cooler (since the same work will require less amps)

You should be running 5s (my idiotic suggestion)



Edit: 5s, 17t pinion, 140mm tire is my recommendation truck will be a monster out there

Many have said that 5s is actually a great sweet spot.
Yet 5s is not a mainstream common pack.

 

[Thumper33]

Here's something interesting. I just found out that the esc doesn't lower the voltage to make the motor go slower, it slows down the wave form, but you're still getting full voltage. With this in mind, you should run cooler on a lower voltage battery because it will not be able to deliver as much power, and thus less heat.

I just ordered a 4s battery and that won't be here for a week or so, but I have a 3s battery here. I would think I'm going to be able to drive the 3s at full speed, so that'll be my next test. I already have the 12T pinion in there, and I'll run on 3s. I'm going to leave the timing at 10 degrees for now so as to not change EVERYTHING at once. If I can get through that 3s battery without overheating, I'll throw the 6s battery on there with the 12T and get some data on that as well.

 

[Thumper33]

I'm beginning to think I have a drivetrain innefficiency or something (as someone suggested). I just did a quick test run over lunch and it's clear that I'm overspinning the motor now as it's peaking at 66,000 rpm (limit is 60,000). Granted that I was able to only flip the truck once this time instead of 3 before, and I'm getting faster on the laps, but I was able to overheat this time in only 3 mins. This was on 12t pinion and still 65% throttle limit on 6s. knowing that I'm overspinning the motor, I'm going to quickly swap back to the 15 tooth and throw the 3s battery in there. While I have the motor out I can look at how hard it is to spin the spur by hand. I assume it should be super easy, but will have a little resistance.

edit: After my test run, I made it 6 mins on 3s, 15 tooth, 100% throttle. I have to say that it's definitely slower than I would have liked on 3s. 4s might do the trick though. That said, I have got to get more run time.

While I had the motor out changing the pinion, I would say that I would find it hard to believe that there was a driveline inefficiency if turning the spur is any indication. It turns by barely touching it.

A side note, on 3s, I did run higher current.

6s (65% throttle) 12tooth pinion -
current peaks were about 42 amps
wattage peaks were about 1000w
motor speed peaks were about 64,000 rpm of 60,000 max

3s (100% throttle) 15 tooth pinion -
current peaks were about 62 amps
wattage peaks were about 600w
motor speed peaks were about 38,000 rpm of 60,000 max

I'm going to conclude at this point that this motor either needs at least a heat sink to run hard offroad. Kinda bummed. I'm happy to try another combo if you want. Maybe I'll drop the timing to zero on 3s with the 15t pinion and see how that goes. I wish I had that 4s battery. I have one on the way though I'll have to mod the battery tray to fit it. LOL It's the 6000mAh offroad battery from smc. weird shorty shape, but is super light for what you get. Only 422g.

 

[slick2500]

I'm beginning to think I have a drivetrain innefficiency or something (as someone suggested). I just did a quick test run over lunch and it's clear that I'm overspinning the motor now as it's peaking at 66,000 rpm (limit is 60,000). Granted that I was able to only flip the truck once this time instead of 3 before, and I'm getting faster on the laps, but I was able to overheat this time in only 3 mins. This was on 12t pinion and still 65% throttle limit on 6s. knowing that I'm overspinning the motor, I'm going to quickly swap back to the 15 tooth and throw the 3s battery in there. While I have the motor out I can look at how hard it is to spin the spur by hand. I assume it should be super easy, but will have a little resistance.

View attachment 210709

How are you hitting 66,000 rpms? 25.2v X 1650 = 41,580 rpms.
The only way you should be able to spin that motor at 66,000 rpms is if you had a 9.5S lipo. 66,000 divided by 1650= 40v divided by 4.2 = 9.52 cells. Something doesn't seem right there.