Single 6374 motor with VESC - Temp problems

[WeeChumlee]

Hi guys

Rebuilt my single motor build - 8S battery, 6374 170KV motor and 97mm wheels - with a VESC.
Unforttunately it will no longer do hills. With the Alien power ESC it never blinked at any hill, but the brakes were totally white.
Was so impressed with the VESC on my dual build that I thought it would be good for my single as well.
Works great on everything except hills. Although there are small heat sinks on the FETs the temp rises very quickly and then cuts the VESC. pretty dissapointed now. A fan is out of the question due to vibrations leaving the only real solution is to go 12S, not something I really wanted to do. Or maybe get a torque boards 12S ESC. Hmmm, what to do???

 

[whitepony]

hmm, maybe this is an sk 6374 motor issue, since Im running 100% the same problems on my trampa despite aluminum heatsinks!

riding my trampa on one vesc meant on every single hill I would have powercuts from thermal issues. wanted to log the vesc temp and when I did that it died on me, several traces on the PCB were burnt and other stuff too ... the german service guy had a long list of failures from overload on that unit. at 40A battery, 60A motor current! :?

 

[WeeChumlee]

Hi whitepony

I was running 80A motor 60A battery.
Strapped my laptop to the board to see the problem. Unfortunately the only smooth asphalt hill was a slight incline 10% at most. Other asphalt casused USB dropouts due to vibration.
Even on this hill I could see that I was only drawing 40A but the temp went shooting up to over 70°C.
On my dual 50mm I can do a 18℅ hill with 40A per motor and no temp issues.
Hmm, maybe try with a SK3 motor but they are always on back order...

 

[whitepony]

ah, thought you had an sk3 motor. im using sk3 6374 190KV x2 on my trampa. maybe its just a vesc thing then. running bldc or foc?

my settings were 80A motor, 60A battery max in bldc mode! when my vesc blew up I was grabbing about 60A motor and 40A battery current, temperate shot straight from 25°C ambient to 60°C when the vesc died on me. :?

is there anything weird about your setup, for example long motor wires or so (its the only thing where my trampa setup differs from others and noone else seems to have heat issues)?

 

[WeeChumlee]

The motor is a Alien power 6374. Don't know how different it is from a SK3 - not much I would imagine.
I am running on BLDC and my wires may be on the longer side but I can't really see that causing a heat problem, but who knows?
No longer or shorter than my dual setup.

 

[RogerD]

I had similar problems with a friends board and a 6374. Switched from a car esc to a vesc and it lost lots of power. In the end we had to go from a 245 to a 190kv motor, and from 6s to 10s.

The VESC doesn't like big amps - much over 70-80. Traditional ESCS allow a lot more through (my EZRun pro 150 passes 110 amps at 6s through to my SK 6374 245 motor on full throttle.

You have to go up in volts to get the amps down, which means expense, to get the VESC to run cool on big single motors.

 

[WeeChumlee]

Yeah, I also think that I shall probably have to go 12S. Means another 4S heavy battery which I did not want.
( or get totally different configuration but that is expensive and wasteful as the 2 4S batteries are good.)
Or get a better ESC for my config? Another waste though. Hmmm
Damn, really prefer my single 63mm to my dual 50mm.

 

[WeeChumlee]

Well, I have now changed to 12S 8000mah configuration. I removed the anti-spark and replaced with a XT90S (wow, these are great, no spark at all).
The battery wires are now as short as they can really be.
I must say though I can see no improvement at all. It does not pull any better and still gets to hot uphill.
Right now I am totally disappointed in my VESC on this single motor build. It may be a settings issue but I honestly do not know.
With the Flier ESC this thing had loads of power (on 8S) for any hill and did not get hot.
Now even with 12S and VESC it has not got anywhere near that power and overheats.
I would really love to hear from others with a single 63mm motor and the VESC. How do they fare and is there some setting to increase the power?
Sure more power may bring even more heat but maybe that can be combated with larger heat sinks - but without the power it is not that much fun anyway.

I am running on BLDC, latest software. VESC 4.10.
Settings are all default except for motor, obviously, and battery cut-offs.
What can I set to improve power?

 

[rmrf]

Where did you get your VESC?

 

[WeeChumlee]

Hi
Got it from Esk8.de
http://www.hellray.de/vesc/

 

[rmrf]

Hi
Got it from Esk8.de
http://www.hellray.de/vesc/

It is hard to tell if sellers are using exactly same parts as in BOM. For example here http://vedder.se/forums/viewtopic.php?p=991#p991 one used slightly different MOSFETs which are slightly cheaper. And again you don't know, even if seller used exactly the same parts, which source he used to buy them. When you do 1000 batch every coin counts.

 

[WeeChumlee]

Well I suppose I could use one of the VESCs from my dual build to test.
Boy this board has been altered many, many times...