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Guide to Buying an Electric Bicycle
Convert the bike that you have?
The first decision to make is whether to convert a bicycle that you have into an electric bicycle.
You can do this, and it is worth thinking about if you have a decent bicycle.
Electric bicycles are not so very different from an ordinary bicycle in the way an electric car is different from the
cars we've known for the last century, with their whole petrol motor, gearbox and drive system being replaced by electric wheels.
Electric bicycles are ordinary bicycles with a small electric motor in the hub of one wheel with a battery and small control attached
to the frame. Plus some wires and a handgrip throttle.
There are two ways to convert a bicycle to an electric bicycle
Either an electric wheel independent of the chain, or an electric motor that drives the chain directly
The most common type is the electric wheel kit. This usually includes an electric wheel complete wheel with tyre, rim and spokes
The hub motor of the conversion kit will usually fit between the front or rear forks of a bicycle frame.
The rims and tyres are usually the wider 1.75" tyres like on a BMX bike.
You'll need to decide whether to have the motor in the front wheel or the rear wheel.This is a personal choice.
Most new electric bicycles come with the motor in the rear wheel. If your front wheel has disc brakes they can't work
with an electric wheel. If your rear wheel has gears then your replacement wheel should have lugs for those gears.
With a motor driving the front wheel you can use the gears effectively to drive the rear wheel and add your effort
With the motor in the rear wheel you have to pedal ahead of the motor to add to the combined power
This means your gears are not effective unless you are going uphill and speed is low.
The type of conversion with the motors that links to the chain your power and the motor add to the going whatever gear you use
The biggest thing against a conversion kit is the adding a 14kg lead battery to the bike in a place not designed for it
If you have a rear rack, strap 3 house bricks to it to get an idea of the feel of having a lead-acid battery on the rack
You'll need to decide whether to spend extra (up to $200) to save weight by having a lithium ion battery instead of a lead-acid battery.
As for electric bikes you can choose a motor power from 200 watts to 500 watts, or even 1000 watts, and you can
choose 24, 36, or 48 volt systems, and 24", 26" or 28" wheels, although the most common wheel would be 26", 200watt, 36volt.
The batteries are either 24v or 36v matching the motor voltage. 36V batteries store more energy and so travel further
There is a big saving in the cost of sending to you, especially if you live in remote parts.
A conversion kit comes in a smaller box and so is much cheaper to send to you.
For most bikes-in-a-box it is not the weight that costs, but the volume of the box.
For a typical box at one third of a cubic metre the "weight" is 83kg which is 2 or 3 times the actual weight
(more like a fridge than a bike).
The sending a whole bike to remote places could cost several hundred dollars but to send a conversion kit would be less than $75.Steel frame or alloy frame?
Having decided to buy an electric bicycle you first decision is whether to get a lightweight combination of aluminium alloy frame
and lithium ion battery or the heavier but cheaper combination of steel frame and lead acid battery.
This choice works out something like twice the price for half the weight, or vice versa.
Very nearly all electric bicycles will be either of those combinations.
There are a few "in between" (both costwise and weightwise) e-bicycles with lighter alloy frames and heavier lead acid batteries.
Serious sports cyclists will pay hundreds of dollars to save half a kilogram on the frame of their mountain bike or racing bike.
But for commuters who don't try to average 45kmh or bounce up 20degree trails a small weight saving is less important.
(Unless they take to the trail or road on weekends as well). For them it may not be worth an extra $500 more less to save 15 to 20 kg.
The lightweight e-bikes are about 18 to 22 kg, the heavy e-bikes are about 35 to 40kg, and the in-between e-bikes are in-between at 27kg.
The most common frame style is the "city" style, more commonly seen on streets of Amsterdam or other European cities.
Our more familiar A-frame bike is less common, as are real mountain bike or BMX frames.Folding or not folding?
Having decided light or heavy, more, or less expensive, you can decide whether you need to be able to fold your bike.
Even if you rarely need to it is good to know you can fold it and put it the car boot, or to store away.
For that it does not need to be light, but if you need to carry it any distance, especially up stairs or
on a bus or train then you would much rather it is light. The difference is rather like an extra suitcase.
And if that is something you would do often then you are likely to think the extra cost is worth paying.The cost?
I have seen maybe 100 catalogues from the factories in China, and not one mentions a RRP, because it's not their concern.
So, beware of any fictitious "save $$$" on RRP.
The prices quoted for electric bicycles varies a lot. Generally $1000 to $2000 for an alloy frame,
and about a bit more than half that for a steel frame. My guess is that the cost of frames and batteries will come down.
The most common batteries are 36V, either SLA or lithium, but some systems 24V to save cost, and some are 48v for either extra power or distance.
The extra cost for a 36V lithium battery could be $150, more or less. It is worth shopping around and comparing well, like for like.
Extra watts of motor power come from the factory at a not much extra price, and so is a minor cost consideration.
It is more do I need it, can I use it? Having gears is probably worth paying an extra $30 or so,
and having lights and basket is worth a few dollars.
As mentioned above getting freighted to you can be expensive, depending as it does on the box size,
rather than weight. Most suppliers would add actual cost, and maybe subsidize that.Electric bicycle motors
Recently the use of highly magnetic permanent magnets has let electric motors become more compact, "smarter", and "brushless".
"Smarter" because electrical feedback circuitry within the motor causes the motor to vary the torque and power output,
as if it had gears, according to what is needed, or how much is being applied by you, the driver.
"Brushless" because thre are no brushes. A pair of brushes like the sparking things in your old electric drill
that were noisy needed replacing sometimes. Brushless motors are more expensive but worth the extra.
Beware that some of the very cheapest e-bikes may still use brushed motors.
These "smart" motors are commonly referred to as PAS, or pedal assistance system, motors. They generally are said to be 1:1.
This means that the motor adds the same power that you contribute when driving in PAS mode.Drive Modes
The drive modes can be either "pedal assist system" or PAS, or hand accelerator, or both, or can be switched off to be neither.
With PAS you and the motor contribute equally to the going, with hand accelerator you can turn it up or down like a motor bike.The Power of the Motor
The legal limit for power assisted bicycles on a road in all Australian states is 200 watts. Repeat, 200 watts.
Because the great majority of electric bicycles made in China (where else?) are made for Europe or US
where the allowed power is 350 watts and 500 watts respectively there are many imported into Australia
with more than 200 watts of stated power. Hopefully at some stage the Australian limit will be increased to 350 watts.
I'll not condone your breaking the law with a higher powered motor, but I think 250 watt motors ought to be acceptable.
The power of the motor is not obvious. The motors look similar, and I don't know in practice the power that gets delivered
to the road can be measured. And as long as you do some pedalling while going along noone will object.
But if you have a high power motor and go along without pedalling, as if on a moped, then you could well be pulled over.
So please keep offroad with the higher powered bikes, if you have one. As a comparison, a fit cyclist produces about 200 watts of power,
so you will certainly notice even 200 watts of extra power, let alone an extra 350 watts.The Battery
Whether it is lithium ion (or less commony NiMH) or lead-acid it will be sealed in an outer case
attached to the frame (with lock) or on a rack above the rear wheel.
Either comes as 24volt or 36volt and 10ah (ampere-hours) or 12ah. Sometime the higher powered motors have 48volt 14ah battery.
The lead-acid batteries are maintenance free and sealed and quoted as being able to be recharged more than 300 times.
There is a variation called silicon lead acid costing a ittle more but supposed to last twice as long.
The lithium batteries are like your computer or phone batteries, but bigger.
They are quoted as being rechargeable 700 or 800 or more times, though I haven't seen testing of this claim.
I suspect that their capacity reduces as they get older as do computer batteries.The distance?
The energy for going depends on the energy stored, and that is the Ah (ampere-hours) times the V (volts).
The distance you can go with that amount of energy depends on the W (watts).
The higher the Ah x V the further you can go, the higher the W (the power that you use) the shorter the distance.
Generally this translates to between one and two hours of driving.
For instance 36V times 12Ah is about 400 (watt-hours) which means you can use 200 watts for 2 hours.
Or 24V times 8Ah is about 200 (watt-hours) or 200 watts for 1 hour.
The higher powered e-bikes will usually go a lesser distance on any battery, because they will go it faster.
How those 1 or 2 hours of going translates into distance depends on the terrain (hills use up a lot of energy)
and the speed (about 4 times the energy to go at 30kph as to go at 15kph) and the stopping and starting (stopping is energy wasted).
The quoted distance that electric bicycles are supposed to be able to go between recharges varies a lot.
Some suppliers are more optimistic than others. A reasonable assumption would be 25 to 50km depending on
battery and power and terrain, plus whatever extra effort and distance you add by your pedalling.Gears or not gears?
The smart motors can put out their power whether the bike's speed is slow or fast,
and having an electric bike without gears is not like a bike in the past when you needed to push hard to get going or go uphill.
If you don't have gears you need to pedal fast or slow depending on the e-bike's speed, but if you have gears
you can easily match your pedalling speed to what is comfortable for you.
It would generally be worth paying extra to have gears.Extras
Just as in a bike shop, there are various extras or options with the electric bicycles.
The brakes are usually applied to the wheel rim, but sometimes they have a front wheel disc brake.
Some may have electric braking. This suddenly turning the motor into a generator and recharging the battery may be a benefit
for the electric cars with much more powerful motors and bigger batteries, but I suspect not so with electric bicycles.
The seats are usually a softish gel unisex saddle.
A basket in front or a box behind the seat are often supplied.
Lights (usually bright LED) and a battery power indicator are often supplied.And to help you decide to get an electric bike...
An electric bike is good for you...
A good regular workout on a road bike will keep you fit, but do you do that?
Quite likely if you use half the power you will do it ten times as often, and so, wouldn't that be good. 5 times as good.
A to and from daily commute on an electric bike is better for you than a weekend workout, and it is more likely.
(But on the weekend you can take out the battery, go for a workout ride, and get hot and sweaty, as well)
An electric bicycle is good for the environment. Every person on an electric bike is a person not in a car.