Without power assist I would be out of the saddle bobbing about and out of breath

[vhfman]

Another ride, this is a 600ft accent in 1.25miles with some quite steep bits, the average is a 12% gradient but some bits are steeper than that. The picture is a screenshot of the GPS route with the elevation and speed profiles. The speed dropped to about 10mph on a steep bit but that was partly because I had to slow down due to the bad road surface and blind corners. Even on the downhill section, which has a sign indicating 12%, the speed was reduced due to the state of the road. My trip computer showed an average speed of 14.7mph.

The BPM hub is performing well. On these short rides which include quite a lot of uphill sections the average power consumption is 14Wh/mile, peaking up to 26Wh/m; that’s with me pedalling enough to get a slight increase in breathing and heart rate but staying seated, I am 100Kg and the bike with battery weighs 23Kg. If I could ride up the steep bits without assist I would be as it says in the thread title, out of the saddle bobbing about, and gasping for breath!

[video=youtube;iicGuq-rADs]http://www.youtube.com/watch?v=iicGuq-rADs[/video]

Chris

 

[Scottyf]

Good stuff. The bpm does perform very well at hill climbs for a hub motor!
What battery and controller amp are you running ?

Good figures anyway And glad your enjoying the build

 

[vhfman]

Hi Scottyf, the battery is homemade 12s4p A123 38V 9Ah. The wattmeter is showing peaks of 28A but I don't know how long the peak power is being sustained as I can't see the wattmeter display while I am on the move. I have not detected any substantial heat build up in the hub, or the controller after a long climb. And yes I am impressed with the hill climbing ability of the BPM hub, which was the main reason I opted for this motor.

I am enjoying the bike; but I am also working on a MTB frame with a Mac Rear Geared Hub motor from cell-man. Which I think will be even better to ride, especially as it has suspension. I hope I have that one going next week.

Now I just hope my knee is going to be OK as I have some real pain in it when I am pedaling at the moment.

Chris

 

[Scottyf]

Sorry to hear about the knee. It would be good to get a comparison against the mac and bpm. A123 cells are monsters for discharge which would allow you to run even higher amperage. But I'd imagine it's already pretty nippy up the hills regardless.

Sounds like your getting alot of fun out of it anyway which is the main thing. Keep us updated on your progress