Project Bandit: the kit

Traveled into Vancouver to pick up a conversion kit from Grin Technologies (ebike.ca).

Given this is my first attempt at a conversion I expect to find components I will want to change or upgrade as it is difficult to know what the impact of the trade-offs are going to be. I figure the best approach is to jump in with best guesses and upgrade as I learn more about the set-up. It's a lot like software development that way.

There are a number key of decisions to make when choosing a conversion kit.

Front or rear hub drive?

Basically what it sounds like. Do you want the source of power to be at the front of the bike (pull) or the rear(push); think front wheel drive vs. rear wheel drive in a car.

In terms of simplicity and weight distribution front hub is probably the way to go. The Bandit project is already going to already be rear heavy and a front hub motor would help but I am going with a rear hub. Maybe I'm just old-school but for the first kick at the can I'm trading the weight and simplicity of the front hub for the predictability of rear wheel.

note: I have seen discussions involving dual hub drives on the Endless Sphere forum but that can wait for a future project.

Direct drive or freewheel/gear drive?

Tough decision. Direct drive provides for regenerative braking but comes with some drag. Gear drives are more pedal friendly (freewheel), and lighter but don't allow for regen. From what I could find on the web there are roughly 3 'mainstream' hub motors to consider:

• eZee - gear drive
• Nine Continent - direct drive
• Crystalyte 400 Motors - direct drive

Since weight is already an issue on this project I am going with the eZee motor. I also like the idea of the freewheel.

Battery?

Choosing the battery was the most difficult for a number of reasons. The battery is the most expensive component and has the most effect on the quality of the ride (power/range) so the key is to optimize the price/range/power.

I am not an electronics whiz by any stretch so it was difficult to understand the trade-offs I was making between volts and amp hours. To put it simply:

• Volts are the power rating (acceleration, top speed, hill climbing, etc) - the higher the volt number the more power.
• Amp hours indicate the range of the battery (how big is your gas tank) - the lower the Ah number the shorter the range

For this project there were three choices:

1. 37 V 9 Amp-hour Lithium-Manganese (this one comes with the kit)
2. 48V 8Ah Samsung Pack
3. 37V 14Ah Polymer

I figured I would want the extra power as I'm no featherweight so I went with the 48V Samsung. At 8Ah I do have some concerns about the range and won't be surprised if I begin to wonder if I should have sacrificed some torque for longer range (36V 14Ah).

Final kit:

- Standard eZee 26" rear drive kit

- Upgraded the battery to the 48V Samsung

- Added the Cycle Analyzer

Total cost (including the lousy new HST) $1700 (CDN).

Now for the build...