ST2 Motor Temperature

devhead

Member
My apologies if this topic has been covered before. I occasionally look at my motor temp after a ride. Lately it has been hitting some new highs. Today it is 167 F. Usually it is under 150 F. Yes I know the weather is warming up but I don't recall the temp getting this high last summer when the bike was new. Is there a known temperature level that should be avoided? I've also seen that my bike reports 32 F when it gets below 70 F. I'm not as worried about this last behavior but it does make me wonder how good the sensor is.

Thoughts, comments, observations ?
 

Neil

Member
I have found that my motor runs warm as well on my ST2 when climbing. I believe hub motors will run warm under heavy load. I have a 4 km climb on my commute home, if I push hard in level 3 I will usually get an over temp warning, I have found that I need to climb in level 2 with speed down and agility and torque around 50% and then I get no warning, obviously I have to work alot harder but that is not a bad thing! The motor will still be warm but that is normal I believe. Other rear hub motors will have similar issues, I think the Stromer is one of the few hub motor e-bikes that will warn you and then dial back the assist automatically to protect the motor. Maybe Ravi can comment on this, he knows more about the Stromer then anyone else....
 

devhead

Member
Thanks for the great description Neil. I had heard the computer would limit the motor if it gets too hot. Do you know what temperature constitutes too hot? I'm looking for a number.
 

Neil

Member
I am not 100% sure but when you are riding you can use the app to check the temp of the motor and battery. It has a line that first turns orange and then red. I think it is around 140Deg.
 

JRA

Well-Known Member
Neil, No I haven't but try contacting Grin directly as they will know if anyone has. They are very good about sharing information.
 

Ravi Kempaiah

Well-Known Member
My apologies if this topic has been covered before. I occasionally look at my motor temp after a ride. Lately it has been hitting some new highs. Today it is 167 F. Usually it is under 150 F. Yes I know the weather is warming up but I don't recall the temp getting this high last summer when the bike was new. Is there a known temperature level that should be avoided? I've also seen that my bike reports 32 F when it gets below 70 F. I'm not as worried about this last behavior but it does make me wonder how good the sensor is.

Thoughts, comments, observations ?

The temp sensor may be out of calibration. After a long climb, it may reach 130F or so but 165F seems a little high.
When you touch the motor, is it really hot?" or is just the reading you see on the app?
 

Neil

Member
Ravi what would you consider a long climb and what time of gradients do you think would be a lot for the bike? I know it is also weight dependent. When I am climbing and I see the assist at max I know that if I keep pushing at that pace and don't back off after 2-3km I will get a warning about the motor getting too hot. Did you ever experience this? Do you climb in level 3?
Neil
 

Ravi Kempaiah

Well-Known Member
Ravi what would you consider a long climb and what time of gradients do you think would be a lot for the bike? I know it is also weight dependent. When I am climbing and I see the assist at max I know that if I keep pushing at that pace and don't back off after 2-3km I will get a warning about the motor getting too hot. Did you ever experience this? Do you climb in level 3?
Neil

Hi Neil,

A long and steep gradient (especially at slow speeds) would be hard on direct drives. Let's say 3+ miles with lot of steep gradients.
I remember my ST2 motor getting really hot on one of the rides that involved 5000ft of climbing in 6 miles but it never touched 130F+
In your case, I still think it is something to do with Temp sensor going out of calibration. How hot do you think it is when you touch it?
 

opimax

Well-Known Member
When I check my battery and motor temps even after sitting over night the motor is always at least 10 degrees warmer than the battery. It is too late to get the exact numbers but I will try to look tomorrow. I don't worry about it but I do think it slightly unusual
 

devhead

Member
The temp sensor may be out of calibration. After a long climb, it may reach 130F or so but 165F seems a little high.
When you touch the motor, is it really hot?" or is just the reading you see on the app?

I've never thought about touching the motor with my hands to check the temp. I'll do that after my next ride. I'd believe that the temp sensor isn't calibrated correctly. Often the motor reads at 32 F. I live in San Diego, it hasn't been 32 F here since 1966. The motor temp almost always reads over 140 F after riding, sometimes 150 and then the recent 167. My rides are typically 30 minutes, 10 miles, only about 500 feet of climbing.
 

JRA

Well-Known Member
Thanks JRA for Grin tech. link on hub motor cooling.

I read a thread on ES today about someone that had taken apart a Stromer motor and I didn't realize that they have an internal controller. Not sure if it is possible to use Statorade in that instance. The Grin boys would know for sure.
 

opimax

Well-Known Member
the last reading on my app shows the battery at 16%, 98.6F and the motor 127.4 this was after/during my last ride , i rode harder than normal that ride mostly on power level 3 and that was the return home battery about 30 miles on it i believe
 

Ravi Kempaiah

Well-Known Member
I'm not familiar with ES forum. Could you elaborate? I would like to follow that thread. Thanks

Don't bother.
@JRA is referring to a very old thread where someone opened up a 2012 ST1 motor.
I will attach the pictures here but the new ST2 motors don't have the controllers built into them and the controller is in the downtube and as a result, they can pump in lot of amps without frying the controller.

This is the ST2 motor

ST2 motor.jpg
 

JRA

Well-Known Member
Don't bother.
@JRA is referring to a very old thread where someone opened up a 2012 ST1 motor.
I will attach the pictures here but the new ST2 motors don't have the controllers built into them and the controller is in the downtube and as a result, they can pump in lot of amps without frying the controller.

This is the ST2 motor

View attachment 16462

I always forget to look at the dates! Thanks for clarifying that Ravi. I still think that if you could seal one up properly and get some in there it would benefit from Statorade though.
 

devhead

Member
Here is this morning's read out after a 10 mile ride in 62 degree weather. The motor barely felt warm to the touch.

upload_2017-5-11_11-31-55.png