My First Ebike Ride

I took my first ride on the electric K2 today, Memorial Day. I was able to ride to my work and back at top speed without charging (about 20 miles), and had significant life left in the battery. Overall I am pleased with how the bike turned out. My main gripe is that there is too much weight on the rear, and so the bike does not handle as well as is could if the weight was more evenly distributed.

The above photo of the bike charging in my garage was taken a few days later. The charger is on top of the battery. Note the Kill-a-Watt energy meter the charger is plugged into. I was interested to know how much (or little rather) it was costing me to commute to work now.

Installation: Making it all Fit

While waiting for the new charger I've installed the rest of the electric components on the K2. Most of this work was fairly straightforward and quick. I found velcro ties to be the best wire securing device, as they are easily moved and will not pinch the wire like a zip tie might. As expected, the axle of the motor was slightly too wide for the dropouts on my bike. I mostly just needed to sand down a little beyond the thickness of the paint inside the dropouts to arrive at a smooth but snug fit. The only issue I've found is that when shifted to the tallest gear, the derailleur hits the motor case side. I don't really plan to use this gear much, if at all, so for the time being I will leave it as-is. If I wish to fix it ebikes.ca said they will send me an additional spacer.
I had originally thought that I would place the controller inside a waterproof pannier as I plan to use the bike in all weather conditions, and the controller is not waterproof. On further thought this did not seem like a good idea as the controller needs to dissipate a significant amount of heat. I ended up mounting it to the side of the rear rack with the cables exiting downward (with a drip loop). I also dismantled and applied silicone to the joints of the controller, as recommended by ebikes.ca.

Charger error

Eager to get my ebike charged to be able to try out the next day, I ended up soldering the connections to the charger last night in the wee hours of the morning. I managed to wire the connector on my battery box with the polarity backwards. When I connected the charger to the box, I heard an unpleasant pop sound and immediately knew I had screwed something up. I sent an email to Ping, and he responded later with a reassuring "Don't worry, we will help you solve the problem". Ping helped diagnose the problem as being the charger and said he would send me a new one, no charge, even though I explicitly said I had caused the fault. My experience with Ping as an eBay seller so far has been outstanding.

A Home for a Battery: The Case

Since my LiFePo4 battery is made up of what are known as prismatic cells, essentially foil packets which are bound together with duct tape, sturdy protection is essential. I chose to go with a pre-made plastic case designed to protect sensitive instruments rather than make my own, as this seemed the easiest route to ensure waterproofness. The case is by Pelican and is the 1300 size. This model of case seems to fit the battery perfectly, but note that Ping can make your battery into any shape or size you want if you ask. I used a waterproof cable gland to make the transition through the wall for the power cable. I used the connector provided with the charger to charge separately. A highly recommend getting a crimper designed specifically to crimp the Anderson Powerpole connector, as this provides a perfect, professional crimp every time. Though it cost nearly $50, I think this is worth it for the ease of use alone, not to mention reliable connections.

Ebike: Patience required

One might notice I have not really gotten anything accomplished on my ebike this month. This wasn't due to a lack of interest, but my planned supplier of the major components, ebikes.ca, has been quite busy this year and is consequently out of stock of the motor and controller I want. The shipment has finally arrived and I placed my order today. The good side to this is that it means that the number of people using ebikes is rapidly growing. However, it seems like I've been itching to get my bike together for an eternity.

Here's what I ordered from ebikes.ca:

Crystalyte 5304 rear hub motor, 26" w/ 7speed
72v 35A controller
Direct plug-in Cycle Analyst
Half twist throttle

I settled on the 5304 as it seems to offer the best mix of a good top speed and hill climbing ability of the 5-series motors. However, there are many who say that the 5-series motors in general are too heavy (25lbs) and are energy hogs in comparison to the 4-series. With my bike, my plan is to not have to pedal at all up the significant hills on my commute. This is also why my battery is so large in its energy storage capacity.

Battery Chemistry: LiFePO4

After some research on batteries the advantages of the more advanced chemistries became clear quickly. Each time one upgrades from lead-acid, to NiMH, to Lithium the battery becomes about half the weight for the same energy storage capacity. As some say "lead is dead", at least in the world of e-bikes where weight is of greater importance.

Though it may seem a bit of a risk, I chose to go with a LiFePo4 battery from the eBay seller pingping227. I was less intimidated by its duct tape shroud due to the fact that others on the ebike forum "endless sphere" have reported good luck with them. Time will tell as far as long term longevity of the battery, but to an extent I am happy to try out new technology. With shipping the cost was $550, which included a free 2A charger. Note that I added the Anderson Powerpole connectors to it as seen in the photo, it does not come with these. This brand of connector seems to be the standard in ebiking now.

Here are the manufacturer's specifications for my battery:

Voltage: 48 Volts
Capacity: 20 Amp Hours
Dimension: 150x220x220 mm ( 6 x 8 1/2x 8 1/2 inches )
Weight: 9.00 kg ( 20.00 lbs)
Charging Voltage: 61 Volts
Charging Current: <5>1000 times

A Home for a Battery: The Rack

I spent a considerable amount of time debating where I might put the battery on the bike. A full suspension bicycle does not offer many options. This ZED DS also does not have eyelets anywhere on the rear. I closely considered a seat-post mounted rack, but was scared off by reports of them cracking under heavy loads. One seat post rack which did look promising was one made by Headland, as it boasts a 40lb capacity (most others are 15-25 lbs max). It is a little on the expensive side though.

In the end I settled on a rack made by Old Man Mountain called the White Rock. The LBS where I purchased it installed it for me, which required drilling and tapping above the rear dropouts due to the lack of eyelets. The upper struts fasten to the rear brake bosses.

Though I am happy with this rack, as it is a strong setup (40lbs capacity) on a bike that was never meant to take a rack, it does pose one problem. If I mount the battery too close to the seat, the seat will hit against it as the suspension flexes. This issue makes my original plan of a large Topeak MTX DXP bag look unlikely, as the height and length (9"-13"x12.5") will surely pose interference problems. I will have to find some kind of suitable box for the battery that is short enough to not conflict with the motion of the seat.

The Unadulterated K2 ZED DS

Here is my recently purchased base for my future electric bicycle. It's a K2 ZED DS 21 speed low-end type bicycle. I had in mind a full suspension from the start, as I plan to use this bicycle as a commuting vehicle and would like it to be as comfortable a ride as possible. It cost a bit more than I had planned to pay for the base, but I couldn't bring myself to buy a Mongoose after looking at them in person. This one also came in multiple sizes, so I think it fits me a bit better. I also liked that it looks more like a "normal" bicycle, as I don't care for the aesthetics of the Y type frame.

The frame is aluminum and the rear suspension arm unit is steel. The rear dropouts appear to be nice and sturdy for the electric motor torque, as this will be a rear wheel drive bike.

It does not have disc brakes, which I thought I might need. However, the disc brakes that come on the low-end bikes do not appear to be much of an improvement over v-brakes. I may upgrade the front wheel to a disc in the future if it turns out to be a necessity.