Electric Bikes - Complete or convert?

I got a chance to ride a new Giant Twist Freedom today. It was schweet!! Then I started to take a closer look at it. No bottle cage mounts. Their bag system for the battery (or batteries, depending on which model) and smart charger prohibits the use of any other type of panniers. So would using any baskets or crates would be out of the question as well.

Then I got thinking about converting my bike (http://www.konaworld.com/bikes/2006/smoke.htm). Probably with a Bionx. This would keep the rear rack free.

Price wise, both options are very close. I've never dealt w/e-bikes before. I would not be opposed to any other conversion kits available, if I decide to go with converting.

Hate to respond to my own post, but I wanted to give a little more info. I'm 6' by 235 lbs. I need to be able to cover around 33 miles daily. Class starts at 0700, then I usually hop a bus to work.

That being said, I don't really understand enough about ebikes to know what I want/need. I have done a little more research and now leaning more towards the Wilderness Energy kit. I originally stated Bionx (they have brand recognition in the market to neophytes like me), but I can get a WE for like 1/3 the price.

Not really keen on the stock SLA's, but I think that I read somewhere in this forum that it would be possible to convert to LiPo's if/when I can afford to do so.

I am not a mechanical/electrical/engineer type, so would appreciate any and all info/advice be kept simple.

Is that 33 miles without recharging or is that a commute where you could charge up? Hilly? San Francisco hilly? Rolling hills? What average speed are you thinking?

Is that 33 miles without recharging or is that a commute where you could charge up? Hilly? San Francisco hilly? Rolling hills? What average speed are you thinking?

-If I used a smart charger, then I would be able to recharge between trips.
-My proposed route has a couple of decent hills, but for the most part has minimal elevation changes. Not quite rolling, but close.
-If I did 15 mph, I would make it to school in about 1 hr and 5-15 minutes. The ride in would have minimal vehicular traffic, but the return would be rush hour.

Well, the BionX has several distinct advantages over the typical direct drive hub motor like the Wilderness Energy or the Crystalyte. It also has the odd disadvantage or two.

Some of the advantages:

+Greatly reduced weight. While you can obtain light lithium batteries for really any electric bicycle, the motor hub of the BionX comes in around 8lbs as opposed to the hefty 15/16lbs of the average common hub motor.

+Greater component compatability. Hub motors currently use freewheels. While 7 is the typical top production number, you can get 8 speeds for many hub motors, although occasionally you need to do some juggling to get it to work well (on my Crystalyte 408, I had to add some spacers) - but BionX is one of the few which will accept a 9 speed freewheel (which does exist),

Additionally, some hub motor manufacturers will claim disk brake compatability (Crystalyte is an example), but the average hub motor is simply too bulky: yes, you can get many of these cheaper hub motors with disk mounts, but you won't be able to fit a caliper between the miniscule working space, making the disk mount useless. BionX will accept a disk brake without issue. I don't know if your Smoke has a disk mount there, so it might be a non-issue.

+Higher machining tolerances. Motors like Wilderness Electric and Crystalyte are made in China for a lower cost. While there isn't anything outright wrong with them and they function very acceptably, the level of tolerance on the BionX is noticeably higher, the axle tends to run truer, the system operates with lower rolling resistance, the overally finish is of a higher quality.

+Regenerative braking. It doesn't really bring back much power at all, but it does help you slow down without wearing out your brake pads at all, and is a nice feature.

The BionX also has some nice touches like the little control console, and the pedelec sensor system. Really, the regenerative braking, control console, and pedelec can all be reproduced on a cheaper system like a WE, but the BionX comes standard with them making them nice little touches.

Downsides?

- Proprietary battery. Repacing the BionX battery is far more expensive than any other brand out there, which is where BionX really doesn't impress me. You need to buy *their* battery, at their price - which is extremely overpriced compared to what you can get a comparative battery for another system at.

- Customization. While you do get a lot packed in to the BionX, you can't really add anything else. The system is nearly locked into the configuration you buy it in completely, aside from a few console commands and such. With WE/XLyte style kits, you have a plethora of different controllers, throttles, battery choices - the kits can really be tailored. This isn't possible with BionX. You're locked out of some *really* good batteries which are out there, like LiFePO4.

Remember that the price of the BionX is fairly high, but that price includes either NiMH or Lithium batteries, and if you purchased an equivalent for a cheaper motor it would bring the prices much closer than you think, and you wouldn't get the weight benefits or any of the extra features. The true cost of BionX is in its higher lifetime operating cost, as their replacement battery prices are quite high.

The small-ish gap when you compare initial costs with lithium for instance, will grow larger and larger over time when you have to spend several hundred dollars more each time you need a new battery pack. Keep the kit long enough to get 2 replacement packs say, and the BionX just became about $800 more expensive than the others once again, on top of the higher purchase cost. Thats worth it for some, but be cautious of this - its one fact about their systems which BionX certainly doesn't advertise.

There are some excellent alternatives out there now. I would suggest looking into BMC. BMC motors has a geared electric bike hub motor out on the market now, which has many of the benefits of the BionX with few downsides. Its very comparable to the light weight of the BionX, but is a far more powerful system with much higher torque output.

Light, customizeable, affordable, compatible with disk brakes, able to accept all sorts of normal non-proprietary battery packs, and as a geared motor it also freewheels, so it rolls much more acceptably with the power off than a direct drive hub ever could. The only real downside to this motor that i've seen so far is in its small amount of noise generation, caused by it having gears internally. Aside from that, the BMC is certainly my top pick.

+Higher machining tolerances. Motors like Wilderness Electric and Crystalyte are made in China for a lower cost. While there isn't anything outright wrong with them and they function very acceptably, the level of tolerance on the BionX is noticeably higher, the axle tends to run truer, the system operates with lower rolling resistance, the overally finish is of a higher quality.

Also note that tight internal tolerances make for a more efficient (and cooler) motor, so you may be able to go farther using a Bionx motor.

Wilderness Electric's motors, unlike the others discussed so far, are of the less efficient brushed type.

I tend to get 1-2 miles per amp hour on my hybrid bike, though I like to ride 20-30 mph on the flats. Hopefully you'll get better mileage at 15mph, but it still could be a stretch to go 33 miles on stock (~10Ah) batteries without recharging.

Last, lower power hub motors are notoriously unhelpful for climbing hills. You will probably prefer a higher torque motor.

No direct experience with the Bionx here, but installing an a la carte kit was fun and worked out better. The only challenging things are finding a way to protect and secure your expensive lithium battery and determining the wiring if you are also getting your own controller. The performance over a ready-made bike or the bionx can be significant. You can get higher capacity batteries (48 Volts +) and higher amperage controllers. The right LifePO4 batteries will give you excellent range, moderate amps, and thousands of charge cycles.

+2 on the BMC hub motor. It's a nice compact motor that allows you to ride your bicycle without motor resistance. I was able to install a BB7 disc brake on it. I think I have the fastest xtracycle in town.

Abney-cat- Thanks for the quick schooling.
Unime-FYI: WE offers a brushless...
Snowranger- I might be able to DIY something w/wife's help. She's an Electronics Tech. She doesn't know anything about motors, but she understands power distribution and PLC's.

I will be googling BMC hub motors.