Ambient operating temperatures for hub motors

[smidgy222]

I'm in Texas where it can easily be 95+ degrees for months at a time. Researching an E Bike purchase but wary of heat issues. Information is provided about the battery, both hot and cold but don't see any information about the motor itself. Contacted the manufacturer of the bike I got my eye on, haven't heard back yet. So is this a thing to be concerned about or not?

 

[Bruce Arnold]

There was a thread about this in the Juiced Bikes sub-forum a year or so ago. I don't recall the details; it might be worth doing a search to find it. I recall reliable information that the motors are designed for pretty much any temperature we'd be likely to find under normal use. I remember that I decided not to worry about it, and I live in North Carolina, where it gets pretty darn hot also. (Couple of 100 degree days already this year.)

 

[Mr. Coffee]

Well, unfortunately it kind of depends on both the motor and how and where you ride.

You are more likely to run into trouble if you climb very long, very steep hills in very hot weather. What "very" means for all three of those is where it gets sticky.

In general if you are on gentler terrain running at high power levels you will be going fast enough (~17+ mph) that the airflow over the motor will provide substantial cooling even in very hot weather. Where you get into trouble is on those steep uphills where you might still be putting out full power but only plodding along at 6mph.

 

[rich c]

I believe the motor is the component least effected by high ambient temps. The controller gets the hottest, but I think the real heat issue will be the battery pack. Not supposed to have it exposed to direct sunlight for long periods. Also, not supposed to charge it if the pack is over 113 Deg. F. Easily over that temp after a hard ride in higher ambient temps and if left sitting in direct sunlight.

 

[smidgy222]

I'm beginning to see why there are few e bikes in shops around here and I don't see them being ridden.

 

[JRA]

There is a product called Statorade that can be injected into a DD motor that helps reduce heat and you can also have a temp sensor with a cutoff you can set to have the motor shut down.

I use both in my DD hubs and while I have run up against the cut off, set at 90c, it was easy to back off and continue on my way and by keeping an eye on my temp in advance it rarely occurs so I can regulate the motor output.

Any electric motor will be prone to overheating if the conditions are right such as high power demand in high ambient temps. Geared hub and mid drives are not totally immune and should be monitored accordingly. That is why a temp gauge can be useful.

 

[smidgy222]

Heard back from manufacturer, the motor will cut off to prevent damage. Like Rich C advised they agreed the battery was the concern, "The main part that would be most affected by the heat is the battery, which you would want to keep in a dry, room temperature environment.", which I find somewhat hilarious as no one rides in a dry room temperature environment.

 

[rich c]

Heard back from manufacturer, the motor will cut off to prevent damage. Like Rich C advised they agreed the battery was the concern, "The main part that would be most affected by the heat is the battery, which you would want to keep in a dry, room temperature environment.", which I find somewhat hilarious as no one rides in a dry room temperature environment.

They are suggesting that to give you a cushion when starting out. Same goes here in Illinois in the winter. A cold soak in the garage is brutal on batteries, the same goes for a hot soak in Texas.