frogblender
10 mW
- Joined
- May 27, 2012
- Messages
- 30
I recently got a new LiFePO4 battery pack, which spends most of it's discharge curve between 52 to 53v, which is substantially more than the 36V SLA pack I used before. The LiFePO4 pack can supply 35A @ 50V into the motor. And 35A @ 50V seems like alot for this motor. At this power, the bike absolutely flies. Acceleration is such that you'd have to worry about spinning out the tire in the wet. Or maybe even the dry. And top speed - well, I don't even know what that is, cuz when I tried, I let go of the throttle in fear as the bike flew through 45,50,55km/hr and was still accelerating.
I can guarantee you my brake wear has gone through the roof.
But now I've become accustomed to 40km/hr, and tend to drive the bike alot harder - higher speeds, and jackrabbit starts. That's where the sustained 35A @ 50V comes in. And 35A @ 50V can easily cause somewhere on the order 500W of heat dissipation within the motor. So that's where my cooling solution comes into play (see http://endless-sphere.com/forums/viewtopic.php?f=2&t=41040 ). But this cooling, powerful as it is, may not be enough; I think I'm on the verge of cooking the 1018 (the smell after I pulled into the garage today was my first clue).
So the question: how much power are you driving into your MY1018Z ???
In my case: Motor is the MY1018Z 450W/24v version.
1) 52v LiFePO4 pack: delivers max of 35A @ 50V sustained (1750Watts) into the motor, motor is well-cooled. 35A controller. Result: Eventually I will probably cook the MY1018.
2) 36v SLA pack: I didn't have instrumentation (Cycle Analyst... a great product, btw) with the SLA's, so I don't know the wattage; same 35A controller. No motor cooling. Result: TWO cooked MY1018's over a ~three year span. Both cookings were the result of the same damn steep hill, lightly mudded, while loaded down with trailerful of kids.
I can guarantee you my brake wear has gone through the roof.
But now I've become accustomed to 40km/hr, and tend to drive the bike alot harder - higher speeds, and jackrabbit starts. That's where the sustained 35A @ 50V comes in. And 35A @ 50V can easily cause somewhere on the order 500W of heat dissipation within the motor. So that's where my cooling solution comes into play (see http://endless-sphere.com/forums/viewtopic.php?f=2&t=41040 ). But this cooling, powerful as it is, may not be enough; I think I'm on the verge of cooking the 1018 (the smell after I pulled into the garage today was my first clue).
So the question: how much power are you driving into your MY1018Z ???
In my case: Motor is the MY1018Z 450W/24v version.
1) 52v LiFePO4 pack: delivers max of 35A @ 50V sustained (1750Watts) into the motor, motor is well-cooled. 35A controller. Result: Eventually I will probably cook the MY1018.
2) 36v SLA pack: I didn't have instrumentation (Cycle Analyst... a great product, btw) with the SLA's, so I don't know the wattage; same 35A controller. No motor cooling. Result: TWO cooked MY1018's over a ~three year span. Both cookings were the result of the same damn steep hill, lightly mudded, while loaded down with trailerful of kids.
