Electric Bikes - Going electric with a Big Dummy
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11-21-09, 10:23 PM
I do just fine hauling 200 lbs or so of stuff up the 3% grade from the small town a mile and a half from my house but am thinking of starting to use the Dig Dummy for longer trips that involve some significant hills (biggest 6% grade 1,000' climb). I'm figuring an electric assist could get me to haul stuff with the Big Dummy on longer trips. The trip to my local Big Box is around 25 miles round trip with total climbing of about 1,200' I'm not trying to do this on the cheap, I'm more interested in the best performance possible. In addition, all things being equal, it would be nice to have batteries that could be recycled at the end of their useful life instead of trashed. I just put in a PV system on the house, so I get to do this without affecting my carbon foot print so economy in terms of electricity use makes no difference to me (or the environment, I've got around 10kwh/day excess capacity in my system). I used to be a professional bicycle mechanic so I am reasonably handy at working on bicycles. So what do you recommend given these parameters?
11-21-09, 11:09 PM
Well, I've seen hub motors used on cargo bikes as well as non-hub motors like the stoke-monkey or the cyclone kits. Personally, I find that the non-hub motor on the kit I installed has excellent torque. (I currently live in the far northern US Rockies and need help on the hills for my knees.) That said, some of the larger, more expensive hub motors have good torque too. Maybe xtrajack or some of the other members with motorized cargo bikes will weigh in.
11-22-09, 06:11 PM
I would look into stoke monkey and ecospeed. The inline motors give more torque for less weight and more efficiency at slower speeds. Keep us informed, please. I am thinking of motorizing my Xtracycle.
11-23-09, 09:44 AM
I have a BionX PL-350 on my Xtracycle. Each weekend I haul 100lbs of groceries, and usually only use assist level 2 out of a possible 4 (at three, the bike really takes off and makes hills effortless, I haven't yet tried 4 under load). I do use level 4 (300% assist) on a local mountain that's a steady 10% grade climb up 1500' (6 miles total distance). Level 4 allows me to climb at 14MPH and uses 1/2 the battery. However, using the regen brake on the way back down gives me a quarter charge back for a net battery loss of 1/4 charge over 12 miles climbing 1500'.
The two things I love about the BionX system for hauling loads are the torque sensor and the regen braking. The torque sensor is great because you use your feet to control the throttle...the harder you pedal the more assist you get, so it's more or less hands free riding. The regen braking is really nice because it's more then sufficient to slow even a 100lb load, and really saves the brake pads.
I've also heard great things about the Stoke Monkey, but haven't tried it myself. If you get it, I'd love to know how it works out.
11-23-09, 01:24 PM
I installed the eZee front hub motor on my Xtracycle. (I was inspired by the Firefly Big Dummy build, that Morgan at Cycle 9 did:
I thought that the front hub motor would allow two drive wheels in the snow. I haven't had an opportunity to try that concept out yet.
It seems to have plenty of torque to help with the hills, Also does well getting across intersections.
I didn't want the supposed extra drag of the regen braking, although as heavy as the bike is a little drag shouldn't be an issue.
I went with the LIFEPO4 batteries. I was lead to believe that the LIFEPO4 has a better cycle life than just about every other battery.
I also believe that it would perform fairly well in the cold. Again I haven't had the opportunity to confirm that.
I really am very happy with my choices, especially the company I bought my kit from. Their customer service is outstanding. They have been very pleasant to deal with.
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