Dual Geared Hubs vs. Nemesis Hill (25% grade)

[Wile E. Coyote]

I'm switching motors around on my bikes again and figured I'd see if dual geared motors could handle my daily 1,000ft hill climb without any pedaling.




I ran the dual motor setup on my usual commute to work. It's a hoot! same 34 mph max speed as running a single motor but scary fast acceleration. The bike also feels better balanced. On the less extreme hill climbs, the motors sounded 'happier' than a single eZee/BMC, no groaning noises. It may be worth keeping this setup to reduce gear wear. On the steepest part of the hill, without any pedaling, I just barely made it to the top without stalling. But the motors did not sound happy about doing it.

So my quest for an e-bike that rides like a normal bike on flats, goes 30+mph, and can climb a 25% grade unassisted continues.

408/4012 - (tried it) too much drag, too much cogging/vibration.
Smaller Wheel Diameter - (tried it) Not stable enough bombing down the hill at 40mph, top speed limited, pedal performance compromised
500 series - (Have not tried) assuming too heavy + pedal performance compromised.
Optibike - (have not tried) - not made of money, top speed limited
Bottom Bracket (have not tried) - Anyone in Seattle got a cyclone setup I can demo?
eZee Kit - (tried it) acceptable performance with different controller/batts, but front wheel skids.
Rear BMC (Current reigning champion ) still needs some pedaling on steep hills.

What should I try next? (other than a car ) Any suggestions greatly appreciated.

*UPDATE*
Changing battery configuration to 10s4p has conquered the Nemesis Hill . I believe the major reason is that the C-Lyte controllers were limiting my output current at 66V (thermal protection of output FETs). At 33V the output FET's are dissipating less heat ant the controller does not limit my drive. Having the a123's 4 parallel also makes for a stiffer supply and less stress on the individual cells.

I'm going to add a "transmission" consisting of a series-parallel switch.

The dual motor setup is TOO MUCH FUN! I'm going to clean up the wiring and make it my daily driver.

So much for exercise :wink: .

 

[ebinary]

Hmm... well I'm finally happy with my Currie USPD Drive, but my requirements are less than yours. I also have a 1000 foot climb over one mile (so a 20% grade). I'm running a BMC 750W@36V Currie direct-replacement (evdeals.com) using 4p Dewalts (so 4p10s). Crystalyte 35A controller.

Climbing the hill without working up a sweat was my goal (not no peddling). I haven't tried zero peddling, but I can do the whole thing quite speedily in my highest gear, breaking a small sweat... or I can do it in any other gear and not break any sweat. I weigh 205lbs.

Personally, I don't want it to perform any better. I want to get some exercise, but I want to have the choice of walking effort vs. running effort.

I'm guessing at 48V, I wouldn't have to do squat, but I don't really want to go there. But of course, I probably will someday.

On the other hand, my Shredder three wheeler with a Lynch motor (similar to Etek) at 36V will fly up that hill, but its drawing between 80A-100A, if I recall. Its got no pedals, so I couldn't help if I wanted to. It does 40mph on the flat.

 

[andys]

Sounds like what you are looking for is more of an electric motorcycle. I have heard good things about the hill climbing ability of the one in the link below. They claim it can do a 30% grade. It uses a 6 phase brushless motor rated conservatively at 3000 watts.

http://www.rmartinbikes.com./evd-electric-motorcycle.html

I would like to test ride one of those bikes as they sound like a lot of fun. Th e biggest headache compared to electric bikes are the very heavy weight, and needing a motorcycle license and registration.

 

[Wile E. Coyote]

I'm thinking about an electric motorcycle for fun, but for my daily commute I need to take some shortcuts that would get me in big trouble on a licensed motor vehicle. The dual motor setup is very close to doing the job. Maybe a eZee front and a Cyclone rear (driving 34T granny gear) would do it?

 

[ebinary]

I'm thinking about an electric motorcycle for fun, but for my daily commute I need to take some shortcuts that would get me in big trouble on a licensed motor vehicle. The dual motor setup is very close to doing the job. Maybe a eZee front and a Cyclone rear (driving 34T granny gear) would do it?

And another parrallel string in your batteries and you'll probably get up. Although Dewalts are supposed to be able to deliver a lot of amps, 4p is noticeably different in hill climbing than 2p on my nemisis, even though the controller is only 35A. Its just a stiffer delivery. And you are driving two controllers!

 

[Wile E. Coyote]

Good Idea!
I was thinking about trying 20s3p. I'll need to pick up some more dewalt packs.

 

[ebinary]

Good Idea!
I was thinking about trying 20s3p. I'll need to pick up some more dewalt packs.

Don't miss this link - lot better than what I've been paying lately...

http://www.toolup.com/dewalt/dc9360.html

 

[Miles]

Sounds like what you are looking for is more of an electric motorcycle. I have heard good things about the hill climbing ability of the one in the link below. They claim it can do a 30% grade. It uses a 6 phase brushless motor rated conservatively at 3000 watts.
http://www.rmartinbikes.com./evd-electric-motorcycle.html

The specifications here simply don't add up, I'm afraid...

 

[dogman dan]

Yikes, that hill looks like it could kill some cars I've had! Obviously the gearmotors rule. Since they freewheel, you could use just the one most of the time. More battery should help even without overvolting. But maybe you could build your own version of a cyclone motor, but with a bigger motor, like 2000 watts or so.

 

[Link]

That dinky little hill? We had one up in the mountains that led to our old house that had to be around 35% I had problems pedaling up it even in first gear.

Dual-motors are nice, though. 8)

 

[ebinary]

Good Idea!
I was thinking about trying 20s3p. I'll need to pick up some more dewalt packs.

FYI - I just hooked my Shredder (three wheeler) up to 4p DeWalts drawing through their BMSs. Shredder is the vehicle that can fly up a 20% grade at 35mph, using 36v 33AH SLA.

With 9.5AH of DeWalts through a BMS, I could not accelerate up a tiny hill without the batteries shutting down. That was the first attempt. I figured I'd probably need six to climb the hill on Shredder, but now I know I need at least 8p to have a shot at it. Or I need to short around the fuse and skip the BMS.

 

[Wile E. Coyote]

And another parrallel string in your batteries and you'll probably get up. Although Dewalts are supposed to be able to deliver a lot of amps, 4p is noticeably different in hill climbing than 2p on my nemisis, even though the controller is only 35A. Its just a stiffer delivery. And you are driving two controllers!

I just tried rewiring all 4 dewalt packs in parallel (10s4p). Made the hill climb at about 10mph without pedaling and ~17mph with walking effort pedaling. That's good enough for me! I'll need to make up a series/parallel switch (break before make!) so the bike will have a speed mode and a hill climb mode.

Thanks for the tip ebinary.

 

[MitchJi]

The dual motor setup is very close to doing the job. Maybe a eZee front and a Cyclone rear (driving 34T granny gear) would do it?

Hi,

Sounds like batteries will get you what you want.

I'm not a big fan of cyclones but a motor using your gears would do it. I recently rode a pi bike. Its only 500w 36v. Whenever it felt slow I shifted into a comfortable gear for pedaling and it would take off:
http://pimobility.com/what/specifications_northamer.html

They state 25% grade and 20 mph. I'm sure that is accurate.

Another solution would be an RC motor and controller. Here is one example:
http://endless-sphere.com/forums/viewtopic.php?f=3&t=5156
http://endless-sphere.com/forums/viewtopic.php?f=6&t=5168

 

[ebinary]

Add another parrallel string in your batteries and you'll probably get up. Although Dewalts are supposed to be able to deliver a lot of amps, 4p is noticeably different in hill climbing than 2p on my nemisis, even though the controller is only 35A. Its just a stiffer delivery. And you are driving two controllers!

I just tried rewiring all 4 dewalt packs in parallel (10s4p). Made the hill climb at about 10mph without pedaling and ~17mph with walking effort pedaling. That's good enough for me! I'll need to make up a series/parallel switch (break before make!) so the bike will have a speed mode and a hill climb mode.

Thanks for the tip ebinary.

Sweet! Its a great feeling to tame the beast, eh?

 

[docnjoj]

Hey ebinary!! I dont want to hijack this thread, but is there info on your Shredder trike. Is it homebuilt?
otherDoc

 

[ebinary]

Hey ebinary!! I dont want to hijack this thread, but is there info on your Shredder trike. Is it homebuilt?
otherDoc

Best post on Shredder is here:

http://www.endless-sphere.com/forums/viewtopic.php?f=12&t=2863

It is homebuilt. I'll post more info when I have it up and running again (SLAs are dead, and I don't have enough lithium yet).

 

[docnjoj]

Thanks for the info on your leaner! I believe that Don Harmon was trying to bring the trike on the stairs to market as the T-Rex. I really wanted one, but it just never happened!
otherDoc