Closer look at wiring loomBike EV
OwnerMichael Evans
Owner's Other EVs1992 Honda Civic
2009 EEV 002
2005 Suzuki Swift-E
LocationRolleston, Canterbury New Zealand map
Email email image
Vehicle2009 Mongoose Mountain Bike
Built from 100% brand new parts
Motor Chinese Brushless DC
750 watt hub motor
Controller 750watt 36V for brushless hub motor
Regen
Batteries1, 36.00 Volt, Lithium-Ion
Lithium Iron Phosphate (LiFePO4)
System Voltage36 Volts
Charger 36V, 5 amp
Top Speed47 MPH (75 KPH)
AccelerationHang On!
Range50 Miles (80 Kilometers)
Seating Capacity1 adult
Curb Weight67 Pounds (30 Kilograms)
Conversion Time2 hours
Conversion Cost$700
Additional FeaturesBike weighed in at 17kg (37.5 lbs) right out of the box. After conversion bike weighs 30.5kg (67 lbs), complete with battery. Top speed is 47kmph, and available range is about 50. Bike pedals smoothly under pedal power and accelerates faster than most cars on electric power. Pedalling does not help to take off as the motor is strong enough to pull away from cars. Before conversion, I had no problem pedalling this bike to about 25 kmph on medium gearing with no wind, but would get tired within a few km's. After installing motor, the bike effortlessly climbs hills, and can get up to 47kmph top speed on flat surfaces, which may be considered a bit too fast for a bicycle.
The bike was my first experiment with LiFePO4 batteries, and I must say
that I have changed my mind about the kind of batteries that I'm going to
put in my car. LiFePO4 are far superior to SLA's or just lead/acid
batteries in so many different ways. Firstly, they weigh just over 1/3 of
what comparable lead acids weigh. Next, they over double your usable range
even if you didn't lose all that weight by switching, and thirdly, they last
for 10 years with proper car and management and can withstand over 3000
cycles. Some minor points, but definitely for argument's sake are that you
don't have to check the electrolyte levels, you don't have to worry about
extra corrosion, and you can place them in existing voids in the car, in any
orientation you see fit.

Sorry about my epiphany on batteries~! My bike is what you asked about.
I bought a kit from ebay user daoji888. The kit contained a 750watt
brushless hub motor mounted in a wheel & tire, the tire is laced like a
motorcycle tire rather than a bicycle tire to handle the torque. The
controller has a regen circuit, and it came with a hall effect throttle, a
digital BDI, and a pair of aluminium brake levers with micro switches in
them for the regen circuit to the controller. Amazingly, they feel like
brakes, but any regenerated electricity is rather pathetic, so no surprises
here. The kit also had a "battery bag" and a flat bungee cord, which I'd
rather not have paid for. I purchased a new 18speed mountain bike from my
local department store and an aluminium bike rack from the local bicycle
store, and a coil of black flexible conduit from the local auto parts store,
along with a few black zip ties and a roll of black electrical tape. Two
hours later and viola'.

The battery pack was entirely a different kettle of fish. It was
supposed to arrive with the kit, however the seller shipped it separately by
air, and lied on the customs documents. The battery arrived in the Auckland
International Mail Centre, and they thought it was a bomb due to the duct
tape and wiring, so they called the bomb squad, who basically closed down
the entire Mail Centre for most of the day, and they blew up my battery.
Afterwards, they phoned me to tell me about it. I asked the Neanderthals in
charge if they ever had the presence of mind to ring me before they blew up
the battery, but they just couldn't wrap their heads around that one. I the meantime, I scored some SLA's to get the thing going and adjusted the final fit using 3 huge 12v 80ah Lead/acid batteries I inherited from a person removing a ups from a security system. Batteries have never been drained at all, so they are in like-new shape after two years on duty.

The second LiFePO4 battery was shipped by surface mail to satisfy the hazardous
materials laws for shipping batteries by air. Gee, Lithium batteries are in
every laptop and cellphone on the planet, and they still don't allow air
shipment of batteries by themselves. Do you think we should tell them about
all those thousands of people who are breaking the law every day? Sorry
again, I digress.

Nevertheless, the second battery worked great, and I put the whole kit
together, as shown, in about 2 hours. There were a couple of things that
needed some additional "engineering". First, the bike rack mounting point
on the front end was shy about 2 inches of bracket, so I had to fabricate
one. Second, the wheel with the hub motor sat off-centre, and I had to shim
out my caliper brake to fit, which took a few minutes to make a 1/2" offset
bracket for the left side, and a 1/2" worth of 1/4" flat washers on the
right. The result is that I moved the caliper brake over 1/2" to match the
offset on the wheel in relation to the frame. Third, the gear side of the
rear wheel needed a spacer to keep the hub from rubbing the derailleur and
fortunately there were several included in the kit. The derailleur has a
narrower axle slot, so I applied a bit of "engineering" to it and expanded
it to the same size as the frame slot, to fit the bigger axle of the hub
motor. I installed a speedometer and a set of LED front and rear lights,
and went for a spin...Scary fast as I'm not accustomed to moving at that speed on a bicycle. Takes most cars off the lights, and up to
about 35mph.

A serious problem came up. The most notable is that I learned that you
should never build a robust, powerful road machine that has inadequate
braking. Certainly, the regen controller provides a braking effect that
would be very good, if you were going the speeds that bicycles normally go.
Part of the problem is other people driving cars and trucks who think a
bicycle should be going a certain speed and are surprised by one going over twice that speed. So, lesson learned: Buy a
bicycle with disc brakes and keep your eyes on the cars!

The next bicycle is going to be a monoshock frame with disc brakes and
front forks with springs. I'm also going to put a nice, wide, soft seat
with springs on it. My spine and my butt are in absolute agony from riding
this bone crusher.

code by jerry