My ESC is too hot?

The ESC in my converted hyper 7 is running too hot. Over the winter this set up has worked well, but the outside temps have warmed a little and they are sure to go up a lot more.

I have a BK 12020, Ubec, 7xl, all on a single 4s lipo (Kokam 3200). 12t pinion, 51 tooth spur. The ESC and wires are all getting very hot (I don't remember what the temp was). It even shut down on me and went into full speed reverse. Crazy! The battery is also getting too hot (160*). I think I will reconfigure my setup to use two 4s packs. That should help in the battery department.

The biggest problem is finding a smaller pinion to try. Mike is out 10t pinions.
Am I headed the right direction try to find a smaller pinion? Would it be hard to take a 4 mm pinion and bore it out to 5mm. Is there anywhere else to find pinions? Thanks in advance.

[MetalMan]

Strange... Your gearing doesn't sound off to me. If anything, it seems like it might be undergeared. Your gear ratio is shorter than the gear ratio I use for a 9L, which is a faster motor! Have you checked for binding? To me that seems to be the only explanation.

No binding whatsoever. Everything spins freely. I forgot to mention the motor was not hot. I think it was around 118* after about 8-10 minutes. It was also running very good other than the heat issues. I didn't even consider going taller in the gearing. Hmmm, now I'm even more baffled.

[Dafni]

Hmm, if your motor stays cool, it would indicate it's not undergeared. But I have to admitt it does not make much sense. I run a similar KV motor as you (1950/6 turn) on 15/51 and 14 Ni cells. And I only have a 99amp ESC (with fans, now)
Binding would have been my suggestion too.
Also, if the wires itself get hot, you must have an enormous amp draw (hot batteries would mean the same) And with this kind of gearing you really should be fine.

Here's what I would look for:
-does the motor spin free when you turn the shaft by hand?
-is the driveline really smooth?
-can't think of anything else... maybe try 12 or 14 Ni cells?
-or check all solder connections

Keep us updated!

The motor shaft does spin freely. I can easily spin the spur gear and drive train with a finger tip. One thing I'm realizing is that the temps were fine up to the end of the pack. Then the temps really spike. I usually stop before the LVC shuts things down.

I'm starting to think that maybe this is more of a battery problem. Maybe two 4s would cure the problem. They would at least cure the hot battery problem.

I still have to check the connections too, but I believe they are ok.

[MetalMan]

I know for sure that Lipo batteries heat up most at the end of their discharge, but I'm not sure if NiMh does the same. Somewhere I've even read that Lipo will still continue to heat up after the load is removed from it!

Ok, I worked like a dog and reworked my buggy this last week. I put the motor on the left side so I could fit two battery packs into it. Of course my motor mount was fine for the right side but not for the left side. The base was two short and it couldn't reach past the flywheel hole. So I had to make a new motor mount. I've got it all back together now. It now accepts two battery packs.

The last time I had it out, it would sputter like radio interference when it was further than 25 feet from me which was unusual. I've never have had any problems with it before. I figure it was my lame radio so I got a MX-3 FM radio.

I had it out today and I was still having some bad sputter/interfrence problem. After about 10 min. the temps were good, batteries were 125*F, ESC was at 130* and the motor was in the 130* range as well.

It ran for about 10 minutes then it went into a insane full reverse! I only had control of the steering. I managed to hit my truck tire where it dug a hole while I unplugged it. I'm thinking that there is something wrong with ESC. Anybody experienced anything like this?

[BrianG]

The ESC could be bad (thermaled enough times and weakened components) or it is only doing what the signal coming in is telling it to do. If you are getting interference/spluttering, the receiver is apparently having trouble catching the signal, and it might have simply sent the full reverse signal to the ESC. I'd check the receiver antenna, check the transmitter battery, try using a receiver pack (no BEC) to rule out a noisy BEC, and try another radio if you have one. Or, it could just be a bad ESC...

[squeeforever]

Yea, I'm pretty sure Sylvester had a similar problem but he was running DSM. Try and reprogram your esc.

[mmdooley]

Hey one thing I ran into was the drive train would turn freely but when you turn the front wheels it would bind. Make sure your axles turn freely in the cups not just turn forward freely.

Originally Posted by mmdooley

Hey one thing I ran into was the drive train would turn freely but when you turn the front wheels it would bind. Make sure your axles turn freely in the cups not just turn forward freely.

Good point. Just checked it and I'm ok. I did find one minor problem when I re-did everything The front motor bearing had worn. There was some side to side play in the shaft. It may or may not have been the overheating problem.

Did some bench testing last night. Reprogramed my ESC, Disconnected the bec and plugged in a receiver pack. I don't know about the interference problem But, figured out that when I hit the low voltage point on the LVC it goes into full reverse. I'm using the Li-saver LVC. At the same time I figured out that my 4s had puffed a cell and was at 6 volts. I wonder if the LVC is toast?

[Dafni]

Li Safer going into full reverse? I hope not! Would be quite bad. I hope the stuttering that I get is not just some ESC cutout under voltage drop.
Some other Li Safer users please comment on this.

[coolhandcountry]

If you read a thread I had it happened to me. If you get the stuttering from the lvc lisaver. it is best to stop then. If it goes on much it will go bizerk. Mine flipped over backwards and swelled the tires up. I ran the spektrum so thought it was that. I have not pushed my lisaver since. The lisaver is for planes and if it goes wide open reverse in a car it is all off throttle for the plane.

[Dafni]

Well, sorry for recomending this LiSafer then. I never had a full reverse on mine.
Maybe we should put up a thread and warn all users about this, a BL MT going reverse WOT is not a nice thing.
Again, sorry for the misinformation. It must have been my ESC stuttering because of the voltage drop.

[coolhandcountry]

It does stutter daniel. It starts with a stutter and then I guess the cells go down to far and it tryies to protect them in plane mode. I have no problems with it after I learned when it starts to stutter be very easy on it or go get it.