Sunday, February 5, 2012

My Electric Bike

I ride an electric bike, and I ride it everywhere - to class and work every day, regardless of weather, and it performs beautifully. It plows right through two-foot snow drifts under its own power, even with my feet dragging through the snow, and with a combined bike-plus-rider weight of 225 lbs, that's no mean feat. While the price tag (approx. $1,200 out of pocket or received as gifts for everything shown in this post; about $900.00 for the lithium electric setup and no thudbusting/airzound frills) might appear to be quite prohibitive, this bike is actually SAVING me money. Here's how:

The bike is a cheap, generic bike I've had for years, so my base cost wasn't too high (nothing). Since converting it and putting my car into storage six months ago, as of this post I have traveled 1,061 miles on it. I've only had to replace one tube (rear) once, and both tires easily have another 1,000 miles left in them. The bike has performed really well, and with the combined savings on gas, maintenance (hooray for no oil changes!), and insurance, I save about $200.00 per month. Since 6 x $200 = $1,200, this means that the bike paid for itself in six months, and that every day from here on out is pure gain. Direct drive motors like this one are projected to last about 5-8 years with regular usage, and at the rate I've been going it'll be about 8 years before the battery dims to only 75% of its charge capacity. In other words, this should carry me well beyond medical school, saving me about $2,400 per year of consistent use.

Component Breakdown:

The Motor: Aotema 750 Watt Front-Mount Direct Drive Motor. The peak wattage of this motor is around 1,200 watts, and something tells me it may go above that from time to time; I've blown three fuses so far... The little tag you see duct-taped to the spokes is the sensor for the speedometer. On flat ground, I average 20-25 mph without pedaling, but with a slight decline (or some fierce pedaling on the highest of 12 gears) the motor will get me up to just under 30 mph - just within legal limits for an unlicensed motorized bicycle.
The Battery: Weighing in at 5.44 lbs alone (6.01 with the mount and cords), the 36V12AH LiCo Water Bottle Mount Battery from AmpedBikes is the best choice you can make in a 36V battery. Sealed Lead Acid (SLA) batteries of equivalent size and power tend to run over 30 lbs and come in huge, bulky blocks that you have to strap onto a rear rack; think car battery. They also tend to poop out when the temperature drops much below freezing, leaving you stranded in the snow halfway home from work on a cold, blizzardy night.

Lithium batteries, however, just can't help being lightweight and awesome (and expensive). With this battery on dry, flat road I get about 20 miles to a charge (about 17 in winter, more due to added clothing (think drag - the air resistance type, not the big-city-Saturday-night-type), weight (stationary inertia!), and lower tire pressure (coefficients of friction - hooray physics!) than to the temperature, which has almost no impact on lithium battery performance), with recharge times taking about 4-5 hours from a bone-dry battery. At my local electricity rates, it only costs about $0.04 for a full recharge using the included charger, which means that I've only paid about $2.35 in electricity for all 1,061 miles so far.

Most interestingly, $2.35 is actually WAY cheaper than it would cost to purchase the food to account for the extra calories that my body would require to power the bike 1,061 miles by pedaling. I would also be willing to bet that the power plant released less pollution in generating the electricity to charge my battery than my body would have with the equivalent end-product waste after eating those required extra calories... I'll be honest - environmental friendliness was more of an added bonus to this plan rather than a driving motivation, but it definitely came out in a way that would please the most avid of tree-huggers. Anyway, back to the breakdown:
On the battery holder is a keyhole to lock the battery to the frame. It's more to make sure the battery doesn't pop out of the holder while I'm riding; I take the battery in with me when I lock the bike up to a rack, just to be safe.
The battery connects to the motor controller via a secure, four-pin screw-on connector. It's never come off, even on the most violent terrain, and is close enough to water-tight that I never have to worry about it in the rain. That screw-like cap you see on the side of the battery at the lower-right is actually the fuse cap - also water tight.
The Throttle: The throttle came with the brakes (see below) in a kit with the motor and motor controller. It's a thumb throttle, and features three bright LED lights: red designating on/off status, green indicating a full charge, and yellow indicating a low battery. Sometimes when I'm going uphill or accelerating quickly, the yellow indicator will flip on as the motor draws a high current from the battery, falsely indicating a low battery charge. As soon as I'm over the hill (or begin to pedal), the light switches right back to green.
The Motor Controller: The motor controller came with the motor kit and is pretty simple; it takes the current from the battery and modulates it based on input from the throttle and brakes before sending the correct signal to the motor. The best thing about it is that it works for 36V or 48V setups. So, If I ever wanted to off-road it in the 35-40 mph range by just getting a different battery, I could.
The Speedometer: Thanks to my awesome wife's bountiful generosity, I have the Bontrager Trip 5W. I have to say, I've never found this speedometer lacking. It's backlit for nighttime viewing, and the units are as customizable as you could hope. It even keeps track of the temperature so I can feel that much tougher when my face skin begins to crack and I see the readout display the temperature as -15 degrees Farenheit, knowing that it probably feels more like -30 with the windchill as I blaze down the snowy road in my electric glory.
The Thudbuster: Whether you're hitting the trails or the train tracks, some healthy seat suspension is a welcome comfort. I can't tell you how many times I got completely racked by an unexpected pothole as I rode down the street at night before I got this bad boy, the Cane Creek Thudbuster. Now, such things have been rendered trivial by the awesome elastic compression suspension shown below.

Note: the Thudbuster above is covered by a protective black sheath, the "Crudbuster," and can be removed and washed if it gets nasty from road salt or mud.
In the above picture, I'm not pushing down on the bike seat. The Thudbuster functions on a four-pin pivot system. Those four metallic circles are pivot points, allowing the seat to ease down and to the back under added strain by compressing the stiff blue rubber discs in the middle.
In this picture, I'm putting most of my weight on the seat, simulating the added weight perceived by the bike seat when I've hit a bump. See how the seat has shifted down and to the back, compressing the blue rubber discs? You wouldn't believe the comfort this affords when transitioning from street to sidewalk at 20 mph... Oh, and notice the awesome shirt that I'm wearing? Complete coincidence, that, but awesome nonetheless.
The Brakes: You can't use regular brakes with an electric bike. A lot of the time I have to break really fast and don't have time (or the where-with-all) to remember to release the throttle with my thumb before I brake. These brakes are integrated into the electric circuit, connecting to the motor controller to effectively cut the power to the motor when squeezed. This way if I forget to release the throttle when I brake, the motor won't continue to propel me toward a fiery death while the breaks do nothing but squeal ineffectively.
The Light: My bike sports the Bontrager Ion 2 light, again thanks to my wife (who needs to write in her blog!)who gifted it to me for my birthday last year. It runs on three rechargeable AAA batteries that blast a bright 7-hour beam of illumination capable of completely obliterating your retinas. It's got some serious brightness, and even easily detaches from the mount if you're worried about some sketchy dude from your neighborhood swiping it while it's chained to your front porch.
The Mirror: I have to admit, I have no link for this mirror, but here's a link to one just like it. I bought it for about $10 from the local bike shop, and it was probably the best $10 of all the cash I've dropped on this bike, given that it has probably saved my life at least a dozen times. When you've got the wind whipping past your ears, it can be tough (strike that: impossible) to hear cars approaching from behind you, inevitably resulting in a near-miss when you neglect to check your blind spot and try turning left only to narrowly escape a bumpy ride beneath the phantom car's tires. Not so when you've got a handy mirror to help you watch your back.
The Flaps: They might seem trivial, but ride a mountain bike to work at 20 mph in the middle of a rainstorm just once, and you'll be singing a different song. I got the SKS Beavertail Fender Set, and though I had to trim them a bit due to my fat mud tires, they haven't disappointed me yet.
The Horn: This is the newest addition to the bike, and therefore it had to be manually added to the overview picture up top. I got this Delta Cycle Airzound Compressed Air Horn for Christmas and recently made room for it on the handle bars, and am I ever glad I did! This baby lets out a blast up to 115 decibels! According to this website, that's as loud as a "Loud Rock Concert or Sandblasting." It's definitely louder than any other car horn, and more than loud enough to be heard by cars that get too close for comfort - or for the random skateboarder or biker who has headphones in and is blasting the tunes while weaving around on the sidewalk in front of me when I'm trying to pass...
Aside from the sheer ripping volume put out by this horn, the next best thing is that the pressurized air bottle is refillable using a standard bike tire pump. You simply lift the white button and underneath there's a regular nozzle for the air hose. Pumping it up to 80 psi gets about 50 half-second bursts of earsplitting noise.
So that's my electric bike: my main mode of transportation and the most fun I've ever had going to and from work each day. Environmentally, fiscally, and recreationally conscientious, my electric bike is one of the best decisions I've made in the last year. If you have any comments or questions about anything, feel free to use the Contact Me page, or simply comment below.


XOXO Dr. Kay Elizabeth said...

OMGosh! Can you make me one? I need a bike, it will make my commute to school way cheaper than it is paying for a bus and train every single day (study hours plus class time)!

Susan said...

This it the best description EVER of what your bike can do! The thing's a beast and sounds like a blast to ride! Nice job! What a riot reading it all! You just may be able to go into business if you ever decide to make and sell them!

Chris said...

Nice pics of the Thudbuster. I've been thinking about getting one for my folding bike that I use for commuting a lot. Even w/full-size wheels, it can be a bumpy ride. I was a little skeptical about how well it works, but looks like I'll go ahead with it now.

Justin said...

Haha, I don't think I'll be mass-constructing these anytime soon... Good luck with the commute though!

Justin said...

Thanks! Let's hope it doesn't come to that, though... :)

Justin said...

Thanks Chris. I don't think you'll be displeased; it has made a huge difference to my daily ride. The only drawback is that I am now much more aware to the jarring of my wrists while seated, haha. If you've got a bumpy ride, you can't go wrong with the Thudbuster.

S.A. said...

Thats a SIKK bike, really nice.

Though I'm guessing the added weight makes it difficult to go on hills (off road)?

Justin said...

@S.A. - Actually no, I've taken it off road with my dog running on some pretty steep trails before, and it does great. It would be a lot harder if I didn't use any of the power from the motor, but with the motor at half throttle I can go off road with no problem. The only issues come up in muddy / icy conditions. Then, the front wheel can lose traction and easily spin out if I give it too much juice. Other than that, it is a breeze.

The Tags

accomplishment (2) AMCAS (1) anniversary (5) application (17) awesome (23) backpacking (8) bike (8) Biochemistry (13) Birthday (1) books (2) Break (46) bummer (2) camping (5) Christmas (4) crazy (30) Curiosity (10) doctor (7) Emergency Medicine (7) exams (37) Fail (4) fun (56) funny (22) Gear (8) God (2) Grand Rapids (2) grey hair (1) Honeymoon (2) Interview (8) iPad (2) Jintus Study (11) MCAT (14) med school (55) Mental Case (1) Motivation (4) Moving (4) MSU CHM (70) music (1) Naiya (22) Nerves (2) News (3) Nicole (40) Notes Plus (1) personal statement (5) Philosophy (1) photos (34) premed (4) random (25) Resources (9) Review (13) Running (6) Scary (2) Schedule (5) Science (1) Shadowing (6) sick (8) Specialty (4) stress (13) Studying (44) surgery (4) Tech (2) Tired (3) Travel (14) Travis (5) volunteering (3) Wife (26)