Board goes into "limp mode". Help!

Both my TB vesc 4.12 and my focboxes overheated before my raptor hubs got warm (the focbox did better), the vesc is usually the bottleneck in most cases.

Both the focboxs and tb vesc 4.12 we’re 70c at the Lowest…

My settings we’re (30 Batt, 60A motor, -10 Batt, -30 Motor)

And 80+ when riding, the fets just can’t handle the current without sufficient cool, I’m betting if I had mounted the vesc outside of my enclosure I wouldn’t have the throttleing issue.

I tried Foc sensored and foc unsensored both had the same efficient, I think this proves that it wasn’t the hubs overheating.

You sure? :thinking: :joy:

I agree with the TB4.12 getting stupid hot in very little time though. My mad hubs (130kv ) would be sitting at around 50c by the time my mosfets hit 90c

I could touch the hubs without ever removing my hands, it felt like lukewarm water.

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What the f :joy:

Not saying you’re wrong, but I thought you ride fast? I’m sure Sean and all the other raptor owners do as well, but why wouldn’t your motors heat up while theirs are dying of heatstroke :thinking:

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Fixed it for you.

Just because in your experience it is the vesc that is overheating first that in no way applies to “most” cases. Your experience relies on one type of motor (raptor hubs), in your type of terrain (?) for your way of riding (?) your settings (30 Batt, 60A motor, -10 Batt, -30 Motor) and your body weight (yesterday’s lunch).

So it would be good to rephrase your statement and not generalize with such a small sample.

FWIW I have had both the motors and vescs overheat on various setups. Depending on the way you ride the vesc or motor can overheat first even on the same board.

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Was doing max speed tests so stop and go, I weigh 115 and managed to overheat

I noticed it if I do normal riding it overheats less.

Also noticed overheating on a raptor 2

My TB 4.12 was also overheating on my dual 6374 setup when I had them.

Can’t remember if I had overheating on my 6355 setup that I had

My dual 6374 SK8’s overheat when my vesc 6 don’t even exceed 45C .

Therefore in most cases it is the motors that are overheating.:roll_eyes:


We’ll vesc 6 has a beefed up heatsink… :rofl:

Also sk8’s are known to overheat.

I am going to be blunt.

You are either thick or trolling. Whatever the case, I am done answering to you.


Alright that last comment was trolling :rofl: but other then that I agree with you that it depends on the case.

It is several things. First it is the simple fact that you are going up a hill with a single drive. Depending on your motor it might be too steep for it to handle. Dual drive will immediately make a difference as your motors will run cooler because it isn’t having to work as hard to power itself up a hill. It could also be the kv on the motor is to high and you do not have enough torques in the motor to power you up the hill.

Fwiw i had an Olllin vesc and at the time a single 5065 in 2.25:1 gearing. The motor got insanely hot (no motor temp sensor) and i never got performance throttle. I burned my hand touching the motor for a sec

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Check your focbox for this classic move:


This film shouldn’t be on your focbox thermal pad. Kind of beats the purpose of the heat transfer pad beneath it.

The amount of times I’ve seen that on prebuilt PC’s lol

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I was surprised when I decided to clean used focbox I purchased and found this. Prebuilt and beginner DIY CPU cooler vibes…

Okay so this is what I’ve gathered from everyones comments:

It could be the motor, it could be the vesc. It’s not possible to tell without realtime data. Going dual will make a difference as the load is shared. I could potentially have the bat/motor max levels too high for a single drive. My gear ratio could be the cause of the problem because this never happened with my old lipo setup that used a 15-36 ratio.

In short - fix the Bluetooth (@Ackmaniac???) and do some testing.

Also, @murloc992, it wouldn’t be that because I’ve moved the speed controller from the standard heat sink to a 3dservisas dual one. The thermal pad is there, although I might replace it to see if that helps keep that area cool.

Cheers everyone. Much appreciated :slight_smile:

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If your motor does not have temperature sensors built in then the hot motor limp mode can not be activated by the vesc. But it can still get hot it just won’t slow you down till it has full melt down. So you can eliminate that depending on which motor you have. Not many have temp sensors.

When I have an issue with my dual setup that puts me on a single motor, there is hill on my way home and the vesc will always go into low power about half way up the hill.

You could try a high gear ratio (lower top speed) this should put less load through the system, or limit amps in the vesc.

I use the eskating 6374 motor which is sensored.

I’m going to order the VESC Project Bluetooth module now.