High temp problems - Hot Bodies D8

[jnev]

Not sure what is going on here with my Hot Bodies D8 buggy. I am running a very conservative set up I think - Mamba Monster, Neu 1512/3D/D (1700KV), Neu 4300mah 25c 5s lipo geared 18/48. Remember the D8 has truggy differential ratios. It is geared for between 36 and 37mph...

The high temp problems have happened before on previous runs with this buggy, but I will use my last run (yesterday) as an example. It was simply a big grass field with a small dirt hill on the side of it. After about 25 minutes of running, the motor is at 190, ESC at 160 and the battery at 125*F (which I am most worried about). Now I could understand if only one component was getting hot, but everything is hot. I also checked the drivetrain for binding, and everything is very smooth. Even with the motor installed, I can push the car by hand and it rolls freely.

I haven't gotten a chance to check the settings on the ESC, but I can't imagine them causing such huge difference in temperature. I am also thinking it may be the ESC sitting so close to the battery that is causing the battery to heat up so much, but I wouldn't expect the ESC to heat up that much in the first place... or at least it never did in my past cars.

Any ideas are appreciated. Thanks in advance!

Edit: I checked the ESC setting and they are all very conservative. Start power on low, timing on 5, punch control on 0% (ran fine like this on my other cars), and LVC at 3.1 volts per cell.

Oh, and here is my current setup (minus a couple upgrades):

[Snipin_Willy]

Things I would check:
Remove the diffs and check for leaking and/or bad bearings.
I see you are running pig tails between your motor and ESC. I soldered my motor wires to remove the extra plugs and lessen my chance of a bad connector, not sure if it helped in my truggy setup yet, but will find out this weekend when I'm at the track (the high is suppose to be 85*F!!!)

[Metallover]

There's gotta be binding somewhere. Or possibly your motor is partially demagnatized...

[MetalMan]

What I would do with ESC settings: 30% punch control and 3.2-3.3v/cell LVC, both of which should help out with heat.

As Snipin_Willy pointed out a poor solder connection (not necessarily your fault) can cause issues, especially heat related issues.

Other than that, does air flow well through the body?

[jnev]

Thanks for those settings MM, I'll change them tomorrow and see how it runs. I checked the bearings near each wheel, and in the center diff, but haven't gotten a chance to check the bearings in the front and rear differentials yet, so I'll do that tomorrow as well. I would think that if the solder connections weren't that good, it would cut out power as well, but it can't hurt to check them.

Thanks again for the help. Hopefully I'll report back with good news.

[zeropointbug]

First of all, I am running the same motor, except finned version on 6s lipo in a Revo 3.3, and after a 30 min main the motor temp was 130F, verified by two different temp guns (cuz I didn't really believe it). The Revo is quite a bit heavier, but I also have better airflow, and a finned case...

I don't really know what else you could do?

BTW, is that tape on the motor to hold the Neu end bell cover on?

[rootar]

alot of us run that motor in buggies and revos and the temps are always amazingly low, id change your start power to high, and punch control on 30-50 %, also if you dont have holes it your body its time to open it up... also gearing up 1-2 teeth would help your motor temp. its sounds like its running at too high an rpm too much....


gear it up and raise the start power to high (low is for 2wds, med is for really light cars, and high is for all the 1/8ths and MTs because they need a good bit more power to intially move, so raising the start power makes it less lilely to cog and makes it easier on the esc....

[zeropointbug]

My Revo was geared for 35mph when it temped 130F (80F day), but it was mostly a steady 1/4 throttle, and one long straight.

But I have found that the temps don't change much even gearing it up to 45+mph on the track.

Do you have any 6s lipo packs? If so, try that and gear for same speed, and try a 4s lipo as well... then see what the temps are. IIRC, when I used to run 7s2p A123 pack, I tried using 5s2p pack, and geared up, it just didn't have the power, and it ran hotter as well.

[wallot]

25 min bashing at grass field = high temps

get it on the track and you will se that the temps will go much lower

[jnev]

Originally Posted by zeropointbug

First of all, I am running the same motor, except finned version on 6s lipo in a Revo 3.3, and after a 30 min main the motor temp was 130F, verified by two different temp guns (cuz I didn't really believe it). The Revo is quite a bit heavier, but I also have better airflow, and a finned case...

I don't really know what else you could do?

BTW, is that tape on the motor to hold the Neu end bell cover on?

The new Neu motors don't have an endbell attached by screws, so the dust cover has no way of holding itself on. The electric tape is working surprising well, and doesn't look too terrible I must say.

Originally Posted by rootar

alot of us run that motor in buggies and revos and the temps are always amazingly low, id change your start power to high, and punch control on 30-50 %, also if you dont have holes it your body its time to open it up... also gearing up 1-2 teeth would help your motor temp. its sounds like its running at too high an rpm too much....


gear it up and raise the start power to high (low is for 2wds, med is for really light cars, and high is for all the 1/8ths and MTs because they need a good bit more power to intially move, so raising the start power makes it less lilely to cog and makes it easier on the esc....

I just changed the setting so hopefully they'll help out. I am about to cut some holes in the body and check the solder connections as well. Bearings throughout the car are all smooth. So you're saying there may not be enough load on the motor for it to run efficiently? I am at 18/48 and don't have a 19t pinion - only a 20t. With the 20t I'll be geared for exactly 40mph. You think that will be ok? I bought this motor for the exact reasons I hear from many others... it runs very cool. Hopefully its simply a matter of changing a couple small things.

Originally Posted by zeropointbug

My Revo was geared for 35mph when it temped 130F (80F day), but it was mostly a steady 1/4 throttle, and one long straight.

But I have found that the temps don't change much even gearing it up to 45+mph on the track.

Do you have any 6s lipo packs? If so, try that and gear for same speed, and try a 4s lipo as well... then see what the temps are. IIRC, when I used to run 7s2p A123 pack, I tried using 5s2p pack, and geared up, it just didn't have the power, and it ran hotter as well.

I just sold my last 6s pack actually a week or two ago. Bad timing... I may try selling this motor and trying out a Neu 1512/1.5y which is 1900KV or a Tekin 1900KV motor both of which I'd assume would run cooler.

Originally Posted by wallot

25 min bashing at grass field = high temps

get it on the track and you will se that the temps will go much lower

I definitely can understand that, although the grass was pretty short. Hopefully I can back out to the track soon, and see how it does.



Thanks for the help guys. Cross your fingers and hope for the best.

[othello]

>Even with the motor installed, I can push the car by hand and it rolls freely.

That seems not right. There should be a noticeable drag when a Neu 1512 is connected to the drivetrain. Remove the pinion and turn the shaft by hand. If it turns freely like a feigao/Lehner your rotor might be (partialy) demagnetised or the shaft is not connected properly to the shaft. If so the motor will compensate the loss in torque by taking far more amps (leading to higher temps of your components) when accelerating but you might also experience a higher revving motor -> more top speed. This might also lead to cogging while starting up as amp draw is much higher then usualy.

Around 4000mAh and a runtime of 25 mins calculates to an average amp draw of only 9.6A (with 18.5V -> 177W average). This shouldn't lead to such high temps. You did not mention outside temperatures btw.

Your tires don't seem to be able to provide super high grip (Amps while accelerating shouldn't be very high). I would expect much tire slip leading to high motor rpms to keep your car moving at a decent speed. This also heats up a motor.

Running on a grass field is challenging for electric components. I can empty my batteries faster on this type of surface as drag is higher and more power is needed -> leading to higher temps of all components.

I would expect your motor to be the root of your higher temps.

[rootar]

yea gear it up, in my GF buggy i run a 1512 3d on 5s and she is not the fastest driver but she can keep it on the track and make pretty good laps, and i have it geared for 40mph and with her drving it "easy" its in the 130s motor, 140s, mod1 mm, and 110 on the protek 5s 4000s, and with me driving it full blast the temps just go up 10-15 degrees.....

gear it up and change your settings and if everything else is good then your temps should be right back in the ballpark you want

[E-Revonut]

Originally Posted by wallot

25 min bashing at grass field = high temps

get it on the track and you will se that the temps will go much lower

This is most likely your problem! Grass is alot more drag than most realize. Esspecially with a buggy, you have smaller tires and not a lot of ground clearence, not only do the smaller tires not roll through the grass easy but your plowing grass with the entire chassis and suspension. Try running on dirt or ashpalt and see check your temps

[zeropointbug]

Yeah, grass field, why didn't I realize that would be the cause of it...

If I run in a large grass football field (off season, not cut), WOT,the motor temps at 165F, that's in a Revo, so a buggy will have a much harder time getting through the grass, would take more power for sure.