Maximum grade to run above 500 watts?

[ga_radwagon]

I know the manual mentions don't go up hills/high torque at above 500 watts to preserve the motor, but I'm wondering if anyone has an idea of what they mean by "hills".
If you're already cruising at 15 mph and then hit a 10% grade, can you keep rolling at 750 watts or should you take it down to 500 max?
I could understand not running at 750 watts on 15% grade starting from 0 mph, but does anyone have a good idea of what is good for long-term motor life?

 

[mrgold35]

I have two Radrovers with the newer controller programming. The old controller would put my max PAS at level 2 for most inclines to keep the watts under 500. The newer controller allows me to use PAS 3 with no problems with any incline and up toPAS 4 with peak watts at 540-550. I like the newer programming because I can increase my mph and less time fighting the hill. I also factor in my weight (260 lbs+gear), bike weight (+75 lbs), elevation (4900-5400 ft on work commute), and headwind (10-15 mph with 20-25 mph gusts). I do apply the throttle on short really steep inclines up to the 750 watts; but, that is only for a 15-30 seconds on average. I really don't use PAS 5 that often with the new programming.

I figure the Hub motor doesn't feel much difference between an incline, headwind, or extra weight. I just try and keep the sustained watts at 550 or less in all riding conditions. I try to keep peak sustained watts 600-750 for short runs for a few minutes max.

 

[windmill]

I use PAS 5 on a couple of 20% hills that are only a couple of blocks long, but I'm also pedaling with a fair amount of effort to keep my speed up. I also do a mile long 15% to 18% hill in PAS 4.
The 2 key factors are not sustaining the load too long, and sharing the effort. If you'r not sure, feel the motor, warm is ok, hot is not.