<Update - 4 years now. Still using it most every day. I now have the battery on the frame.>
I have been using this for 3 years now and have about 5,800 miles on it. About 580 charges. This is about the expected life of the battery, so I am not TOO disappointed that the battery went up in smoke last week (I am grateful the battery bag did not catch fire). I am still trying to find a 3rd party battery that will for sure work (without doing a trial by error thing). Technically you need to be licensed to ship a lithium battery via USPS/UPS/FedEx, so they are not legally returnable.
I have the lithium-battery in the bag version because I felt it would be easier to carry into the office to charge and be better protected from the elements and bumps and less advertizing that I had a nearly $2,000 system on my bicycle, come steal me.
The bag they use is a very nice customized Arkel rear rack bag. I keeping the controller inside the bag, protected and hiding the fact that I have a motor. I cannot change the settings this way while biking, but it has never been an issue for me.
I chose Bionx over other manufacturers because of the ability to use it without a throttle (in fact, I have not used my throttle even once yet). Setting 1 provides a 25% boost (of your existing effort), 2=50%, 3=100%, 4=200%. You pedal, it helps. You stop peddling, it stops helping. Just like normal riding, but you now have bionic legs. On April 1st, I set it to 4 going to work and 4 going back and gradually get it down to setting 2 so I can still decent exercise without pushing my knees into pain territory.
It is one of the narrower options which allows for as well as 9 speed freewheels and has mounts for disk brakes should I upgrade to such a bike in the future.
It also attaches to the rear wheel. Most front-wheel hub motors will destroy suspension front forks.
I wanted a wheel that would fit on my existing trusty 20 year old bike rather than a new bike that I may not like riding (especially those with tiny wheels on the Chicago's potholes for 3,000 miles per year carrying a 250lb load).
I went from an average speed of 13 mph to 19 mph over 10 miles. Essentially I ride 5 gears higher than before.
Speaking of Chicago's potholes and riding over them with 250 lbs of weight over the rear tire at 18mph... This is way too much stress for the Bionx rim and after three replacement rims (each of them split on me and stopped me immediately and once nearly threw me off the bike and each time distroyed my kevlar tire), I finally paid the LBS to install a high grade rim (rhyno lite). So far the rim has stayed together, however until I replaced all the cheap spokes that came with the BionX wheel, I was breaking spokes left and right and always carry 178mm spokes with me (for a 26" wheel).
I did need to hunt for an 11 tooth freewheel (not cassette) and a 46T Chainring to be able to maintain 20mph without peddling so much, but most Bionx vendors will have one (tho my LBS did not).
In the beginning I bought the charger with me in the bag, but after having TWO of them fail on me (I guess they are not made to take the bumps of city streets), I broke down and ordered a 2nd one so that I could keep one at work and one at home.
I do know know about the battery in the white box, however the battery in the bag does not have a good connection from the battery to the thermometer attached to the battery and it has separated twice now. The first time, the bike shop sent it to Bionx for repair (which took forever with customs as they are in Canada). The 2nd time, I just soldered it myself and it has been fine every since.
I have been commuting via bicycle all my life, but as I get up there in years and moved farther away, it just became too much for me (especially my knees) to ride daily. With this motor, I am back to daily riding (Yeah!). For the first time in many years, my knees are pain free once again.
I chose the Lithium option because it performs better in the cold (in theory), since I ride from April 1 to at least the first snowfall that sticks.
Unlike a scooter or motorcycle option, I can legally park this on the bike rack on the sidewalk right next to my building and carry it into my basement.
It does add substantially to the weight of your bike.
I never spent the time connecting the "brake to trigger regeneration" as it would be just one more thing to fiddle with. My battery never runs low enough to require the little regeneration it provides. If you had to go down hills a lot however, I can definitely see the benefit of connecting it, no braking required. However, there are not many hills in Chicago.
I do wish that Bionx officially supported 3rd party batteries. Their asking price of $1,000 for this battery seems to be highway robbery. However there are sites out there that explain that as long as you buy your first battery from Bionx, you can use their battery controller chip (PCB) and hook it up to a third party battery. This was another reason for wanting the bag battery as it seemed so much easier to re-wire and fit a 3rd party battery.
Be sure you double check that you received all the correct parts. The box we opened at the bike store included the 24 volt battery in the box. Everything else (including the charger) was for the 36 volt kit.
The system occasionally freezes up while biking. Basically it just stops helping you while you are pedaling, but works fine after you unplug the controller and plug it back in again. Probably about once every 500 miles or so.
The quality of the rim, spokes and charger is needlessly low for the money it costs, and I have no idea why they cannot better secure the electrical contact to the battery, but the engineering inside the hub is probably the best out there and they are using a higher end battery. The motor itself has worked flawlessly as near as I can tell.
My 37(42)Volt 9.6 amp hour battery would get me back and forth (20 miles) in one charge no problem in the beginning, even on setting #4. However, 5,000 miles later, the gauge showed it as completely drained after 20 miles the last time I forgot to charge it and that was at setting #2.
After three Bionx rim failures, I installed it into a 26" rhyno lite rim.
Here are the 178mm spokes I am using:DT Swiss Champion spoke, sil 14g - box/100 178mm
After the Bionx spokes kept breaking one by one, week after week, I finally gave in and just changed them all to these Champion spokes and I have not had a broken spoke since.)