TP Power Motor Efficiency and Waste Heat Comparison

[Logan's_Rcs]

Good morning

I recently stumbled across this video:

that describes how to calculate the amount of energy loss (heat) from a brushless motor. I took these values to calculate the loss from TP motors, as I have used a couple in the past, and found some interesting results.

First, I used to run a 4060 1730kv, and it got hot in everything I put it in. Couldn't even keep it geared for around 50mph for bashing without it getting hot. I got another one, and the same thing happened, so it was unlikely a defective motor. I used these calculations in the video, and found that this motor's losses come to a total of 245 lost watts. I then compared this to the 4060 1350kv, using the same voltage, and it appears as though the 1350kv is more efficient because it's losses only come to 171 watts of waste heat.

Now my question is, just how much power is 74 watts? Is that a decent amount of energy to be gained in the 1350kv, or does it not really matter? Would there be a big difference in heat between these two motors?

Thanks for your thoughts!

 

[Sandracer_NL]

Now my question is, just how much power is 74 watts?

 

[LibertyMKiii]

Were both setups geared to hit the same 50 mph?
Usually things end up evening out or darn close to it.

With that said in general lower KV does run cooler in my experience

Probably the better way to look at it is if you are pulling 150a and 20volts (150*20= 3000 watts)
75 watts is 2.5% which is great.

The other at 171 watts is around 5%, which is still not bad.

 

[@9G]

I'm no expert but that 4060 can is a smaller can which from my experience adds to the heat especially if your gonna be bashing. You also have to take into account where you're bashing because off road on grass or even dirt is gonna require more work from the motor as opposed to street bashing in a parking lot/on road surface. If you're of an off road guy then a bigger can like a Castle 1717-1650KV or HobbyWing 4985-1650KV would be way better in terms of heat...and a lot safer. I only use TP motors for on road use. I've used a 4050CM 2300KV (slightly shorter than the 4060) on 6S and 8S on road only and it was magnificent. I've also used the big boy 5650 1440KV and 1450KV on 8S for on road bashing and they're great as well because I can gear them higher to make up the speed and not worry about overheating. I also run fans on everything. If I were to use a TP motor for off road I'd go even lower on the KV (less than 1500 and even around 1000 to 1300 to be safe) with modest gearing and I'd use the bigger can size (54..,56..or even 58..). Those TPs can heat up quick but if you gear them right, take into account vehicle weight, can size, and the surface you're gonna run on they are some of the best motors you can buy for the price. I'd stick that 4060 1750KV in a smaller car (1/10th scale and under) and gear it for the surface. It's probably got tons of torque for such a small can but it needs a lighter car to keep the heat down...and some fans.

 

[Logan's_Rcs]

I'm no expert but that 4060 can is a smaller can which from my experience adds to the heat especially if your gonna be bashing. You also have to take into account where you're bashing because off road on grass or even dirt is gonna require more work from the motor as opposed to street bashing in a parking lot/on road surface. If you're of an off road guy then a bigger can like a Castle 1717-1650KV or HobbyWing 4985-1650KV would be way better in terms of heat...and a lot safer. I only use TP motors for on road use. I've used a 4050CM 2300KV (slightly shorter than the 4060) on 6S and 8S on road only and it was magnificent. I've also used the big boy 5650 1440KV and 1450KV on 8S for on road bashing and they're great as well because I can gear them higher to make up the speed and not worry about overheating. I also run fans on everything. If I were to use a TP motor for off road I'd go even lower on the KV (less than 1500 and even around 1000 to 1300 to be safe) with modest gearing and I'd use the bigger can size (54..,56..or even 58..). Those TPs can heat up quick but if you gear them right, take into account vehicle weight, can size, and the surface you're gonna run on they are some of the best motors you can buy for the price. I'd stick that 4060 1750KV in a smaller car (1/10th scale and under) and gear it for the surface. It's probably got tons of torque for such a small can but it needs a lighter car to keep the heat down...and some fans.

Interesting thoughts, but I don't think that can size has everything to do with heat. While bigger cans do generally run cooler, I've experienced a castle 2200kv running much cooler than my tp 4060... For reference, the 1515 is a 40x74 and the 4060 is a 4092... So I think amp draw/iron and copper losses do play a large part in motor heat, not just can size.

Were both setups geared to hit the same 50 mph?
Usually things end up evening out or darn close to it.

With that said in general lower KV does run cooler in my experience

Probably the better way to look at it is if you are pulling 150a and 20volts (150*20= 3000 watts)
75 watts is 2.5% which is great.

The other at 171 watts is around 5%, which is still not bad.

I never had the 4060 1350kv, so I'm not sure how that would perform. However, it did run warmer than my castle 1515 when geared for the same speed... I guess I'm just wondering if whether or not the copper/iron loss differences could really change the amount of heat that a motor produces.

 

[LibertyMKiii]

I never had the 4060 1350kv, so I'm not sure how that would perform. However, it did run warmer than my castle 1515 when geared for the same speed... I guess I'm just wondering if whether or not the copper/iron loss differences could really change the amount of heat that a motor produces.

That is very abnormal. Maybe something wrong with that motor?
Or a situation with wear items on the car like bearings?

 

[Logan's_Rcs]

That is very abnormal. Maybe something wrong with that motor?
Or a situation with wear items on the car like bearings?

I had two 4060 1730kv motors, both ran warmer than my 1515... nothing changed in the car when I swapped motors, I tested them back to back.

 

[LibertyMKiii]

I had two 4060 1730kv motors, both ran warmer than my 1515... nothing changed in the car when I swapped motors, I tested them back to back.

That is interesting.
What RC car was it? Also which ESC?

When I ran the 1515 in a 6s Arrma it ran hot. Same experience others had too.

 

[Logan's_Rcs]

That is interesting.
What RC car was it? Also which ESC?

When I ran the 1515 in a 6s Arrma it ran hot. Same experience others had too.

I was running the mamba monster x6s esc, and I was actually putting the motors in an arrma big rock 3s. I was trying to get it going really fast with little to no heat... I since have moved on to a Tekno MT410 and have been running an MMX8S 1520 combo geared for 65-66 mph it doesn't get over 125 degrees running for 10 min in tall, wet grass and 70 degree weather with fans on the motor. The reason why I'm asking about these TP motors is because they are cheaper than castle, and I am looking at building a Hobao Hyper SSTE, and would like to get insane amounts of power with cool temps.

 

[Moirae]

I remember logan always saying his tp ran hot and I remember always thinking it was weird AF or his definition of hot was very different than mine. Granted I don't have that many tp 4060's, but the few I have are good. We have the 4060 1750kv in 2 outcast rigs and they're great. Geared 23/50 it can get a lil toasty on a hot day but nothing too crazy. I've had a 4060 cm reach 250f and still work perfectly fine to this day. I'm a much bigger fan of the 4070 though and I always go bigger where I can. 4070 temps definitely better than 4060.

Make sure that timing is on 0

 

[Logan's_Rcs]

I remember logan always saying his tp ran hot and I remember always thinking it was weird AF or his definition of hot was very different than mine. Granted I don't have that many tp 4060's, but the few I have are good. We have the 4060 1750kv in 2 outcast rigs and they're great. Geared 23/50 it can get a lil toasty on a hot day but nothing too crazy. I've had a 4060 cm reach 250f and still work perfectly fine to this day. I'm a much bigger fan of the 4070 though and I always go bigger where I can. 4070 temps definitely better than 4060.

Make sure that timing is on 0

The 4060 I had in the big rock got up to 176 degrees within 5 minutes of driving... I'd consider that to be decently hot.

 

[Moirae]

The 4060 I had in the big rock got up to 176 degrees within 5 minutes of driving... I'd consider that to be decently hot.

Me too, I've never in my life had a tp motor get that hot that fast and I have like 28 of them X_X I'm so curious as to why your experience has been so different. That makes me wonder if maybe you weren't geared high enough and spent the whole 5 minutes WOT? I don't know but you're definitely an outlier.

 

[KnowAir]

Me too, I've never in my life had a tp motor get that hot that fast and I have like 28 of them X_X I'm so curious as to why your experience has been so different. That makes me wonder if maybe you weren't geared high enough and spent the whole 5 minutes WOT? I don't know but you're definitely an outlier.

I can't speak of the technical aspects of these things cuz it doesn't interest me TBH. I did however see Aldo's TP powered Kagama go over 300f!! Wow!! That is some testimonial for TP motors!! Whew!!

 

[LibertyMKiii]

Me too, I've never in my life had a tp motor get that hot that fast and I have like 28 of them X_X I'm so curious as to why your experience has been so different. That makes me wonder if maybe you weren't geared high enough and spent the whole 5 minutes WOT? I don't know but you're definitely an outlier.

This is a really good point.
More time at high RPMs will generate heat faster. This likely is the issue knowing how hard it is to fit gearing in those plastic rigs.

As always it is all about picking the right motor for the application and voltage that will be used.

 

[SrC]

Make sure that timing is on 0

+!
Advanced Timing just creates high temps, with little if any marginal gain in performance anyway. Adv. Timing just increases RPM's a bit. While Trading off some Torque with that.. And some motors simply can't handle it.
Especially "D" wound motors.

 

[KnowAir]

This is a really good point.
More time at high RPMs will generate heat faster. This likely is the issue knowing how hard it is to fit gearing in those plastic rigs.

As always it is all about picking the right motor for the application and voltage that will be used.

I've done that.. missed the mark on kv choice. Too much time too deep with the trigger finger will result in overheating for sure.

 

[Logan's_Rcs]

Me too, I've never in my life had a tp motor get that hot that fast and I have like 28 of them X_X I'm so curious as to why your experience has been so different. That makes me wonder if maybe you weren't geared high enough and spent the whole 5 minutes WOT? I don't know but you're definitely an outlier.

The thing is, I actually geared down and the motor got cooler. Something just wasn't happy with either of those motors, and I'm still confused to this day lol.

 

[LibertyMKiii]

I think they want to be in an 6s boat LOL

 

[Logan's_Rcs]

I think they want to be in an 6s boat LOL

Maybe!

Anyways, do you have any recommendations for a motor for the SSTE? I'd love to give TP another shot, I think the raw power is almost unmatched, but then again, I've had heat issues with every single motor. That's why I was looking at the iron/copper losses to see if I could calculate which motor would be most efficient before purchasing one.

 

[LibertyMKiii]

Maybe!

Anyways, do you have any recommendations for a motor for the SSTE? I'd love to give TP another shot, I think the raw power is almost unmatched, but then again, I've had heat issues with every single motor. That's why I was looking at the iron/copper losses to see if I could calculate which motor would be most efficient before purchasing one.

What is the setup for the car?
6s?
What type of tires?
Planned peak speed?