Motors and heat. How hot is too hot?

[Shane]

So there doesn’t seem to be a general ‘motors’ thread so posting this here. I’m tossing up between a Giant Trance E+ 1 (Yamaha) and the Trek Powerfly LT9 (Bosch). I’ve ridden both (love em) and am testing both side by side next weekend, looking to make a decision and purchase the week after.

I live in Australia and we are about to move into summer here, with temperatures that get up to 45 Celsius.

Now on days that hot I doubt I’d be riding anyway but it’s gotten me thinking, how hot is too hot for an Ebike? Is there a built in cutoff to prevent damage? And would either the Yamaha or Bosch motor have an advantage in this area?

Cheers

 

[R120]

The motors do have cutoffs to prevent overheating. On the first generation of EMTB's this was more common, but seems to be a rarer occurrence now (we haven't seen a thread on here about it for example)

 

[MattyB]

I’ve not seen any data on heat generation/dissipation of ebike motors, so I don’t think anyone here can provide much more than a guess based on the performance of their own bike in their own climate. All we can really say is that heat generated through use is the dominant factor over ambient temperature - it you are running it consistently at high output it will get hotter than if cruising. That means heavier people who ride in hillier places will generate more heat in their motor than lighter riders in flatter places.

 

[Wiltshire Warrior]

you need to consider the batteries too - Bosch only talk about 0-20 Deg C !