The "assistance"?
All electric bicycles have had "pedal assistance". With that control the motor kicks in
when you have started pedalling and turns off soon after you stop pedalling.
In many places this is the only permitted control.
While the motor is on feedback from the motor makes the controller add more power when you pedal
harder for hills. However the variable assistance is not very subtle and it is hard to dawdle the bike.
Its difficult to manoevre through people on the path, or to give yorself a nudge to get through a
narrow path without the motor kicking in too much.
We are permitted to have a much more useful control - a handlebar throttle.
With this control it is easy to turn up or down the amount of assistance the motor provides...
as little or as much as you need, or want...
from doing your normal pedalling and giving that a speed and power boost to
taking it easy, and assisting the motor, a little, lot, or not
However to make the best of this control you need a bike that allows the pedal assist control and the
handlebar throttle to be switchable, and so not being on at the same time.
If you want to control your effort and the motor's assistance you do not want the
pedalling to kick the motor into action controlling the assistance, rather than you.
Many electric bikes may have a hand throttle, but not a switch to turn off the pedal assist.
Ask about that. It may not be mentioned. Most of my bikes now do have this feature.
The power of the "assistance"?
We are allowed to have 200watts of assistance.
That is the motor can have 200watts output. This is because that is about what a reasonably fit
cyclist can do unassisted. (A Tour de France could manage double that, and for 4 hours, but not you or I)
So what can 200watts do? On flat going 200 watts will go 25kmh, plus or minus depending on the
set of the motor (or what its maximum is set to be) and of course less on hills, depending on the
slope. With the 200watts and something approaching that from you and gears you will be able to ride
up just about any hill you would want to go up. And it will be much easier, and several gears higher
than it would be without the motor.
In US the permitted power is 750 watts, and there is discussion about raising the limit here to ?.
280watts, 40% extra power, will add about 4 or 5 kmh to maximum speed on the flat but will add
40% extra speed going up steep hills. I've tested that on some of the more powerful bikes that I have.
The more powerful 350 watt bikes are very "easy" as pedalling is only necessary on steepest of hills.
Note that a more powerful motor does not necessarily mean higher maximum speed but
it does mean a proportionately faster speed uphill.
Motors vary in how peaky or flat their output performance is over a speed range.
For instance my light alloy folding bikes (09 and 10) are about 3 kmh slower than their big brother
bigger frame bikes (06, 07 and 08) on a flat street but are about 3 kmh faster up the hillclimb.
How far will an electric bike go?
On one recharge that is.
That depends on...the bike, the battery, the terrain, the ride, the day, and you
The battery....its voltage, its AH, the ampere-hours, and its age...
(the product of the V and the AH is watt-hours, and that is the energy available to make the bike go,
although there will always be some energy left that can't be used).
The capacity of any battery reduces with its age (see below)
The terrain....hills have a very big effect
The bike....it's weight, its condition, whether the tyres are fully pumped, the brakes drag
The ride....the speed, the stopping and starting
At full speed the range could be a third less than it would be at around two thirds of max speed
because the efficiency of the motor is much less when it is running cose to its maximum speed, and
frequent stopping (wasting kinetic energy)and starting (motor is inefficient at low speed) will
reduce the range, especially if the starting is full throttle (a bigger drain on the battery).
The day....less if it's windy, or very cold
And you....how much effort you contribute yourself
As a guide, a fit cyclist could sustain about putting out energy of about 150-200W,
which is just what they allow us to have as "pedal assistance" with an electric motor.
Except for a few of my e-bikes meant for short distance commuting, such as the 24V folding e-bikes,
most have 36V and 10 or 12AH batteries.
You will see greatly varying quoted "range" on advertised models, but always go by the V x AH
and divide that by 6 to 10 and then take off some for age of battery, and that they never
use all the energy. The higher the Volts, and the higher the AH the longer is the range.
Tips for getting a greater range.
1. keep tyre pressure up (this also reduces the chance of a puncture)
2. accelerate slowly, and
3. anticipate stopping and use the momentum to glide to a stop.
What types of battery are there?
At present there are two types of battery commonly used...
Sealed lead acid batteries and various compounds with lithium.
Its weight versus cost. About 3 times as heavy versus 3 times as expensive.
While the cost of lead acid batteries is largely determined by the cost of industrial lead and
sulphuric acid, both of which are rising, the cost of the lithium ion batteries is largely
determined by the technology rather than the cost of the lithium compounds, and is likely
to become less with volume production. The sealed lead acid batteries are made with 2, 3 or 4
small 12 volt batteries connected in series within a case. "Sealed" means just that...
no vent, no need for topping up, no need to be kept upright.
The lithium batteries are like a bigger laptop battery. They are made with a stack of many
3.7 volt cells in series. There has been, and continues to be an evolution of various
lithium compounds, co-compounds, and compositions aimed at better performance, delivery and "life".
The lithium batteries used in electric bicycles are generally refered to as being "lithium-ion".
The "lithium-ion" is the cathode of the battery. There has been an evolution of lithium-ion formulations.
The most commonly used is Lithium Manganese Oxide (LiMnO2).
This is a safer and less toxic compound than earlier ones using lithium and Cobalt Oxide.
A better cathode formulation than the common LiMnO2 is Lithium Iron Phosphate (LiFePO4, or LFP).
A battery with LiFePO4 can have twice the life, (up to 2000 charges) and is more stable and safer in use.
These are likely to be the battery powering e-cars, e-trucks, e-buses, and e-bikes too.
They cost a little more (about %20) but the extra cost is worth it for the extra "life".
Why aren't LiFePO4 batteries used more? Probably because they cost about 20% more.
A technology for the near future (just starting to be used for electric bicycles) are capacitance
batteries...A giant capacitor about the same size and weight as a lithium battery and also holding
about the same energy but, at present costing more, whose advantage is very rapid charging.
What is the "life" of a battery?
There is no predetermined "life" as such.
It's just that by the time the battery only has 60% of its original capacity it is losing capacity,
and usefulness, quickly and for most purposes needs to be replaced soon, and so that's it's "life"
The battery factories test their batteries with a series of charge/discharge cycles.
Of course they don't get on a bike and ride it for 2 hours each time, but instead discharge in the
laboratory through a resistive load. They produce a capacity versus discharges chart and a certificate
saying 300, 800 or 2000 etc discharges to reduce the battery's energy to 80% of original.
In practice, on the streets, however, a battery may not do so well.
There are many factors that affect how long a battery will give a useful service.
To start with all batteries will deteriorate by a small % every month, however they are used,
and even if not used. Other factors affecting the battery include rough treatment,
and being kept or left in a hot place (or being left in the sun).
Partial discharge/recharges should give proportionally more recharges.
Neither type of battery should be left unused unrecharged for more than a few months,
however they should also not be left for a long time fully charged either.
About half charged is better.
More About Lithium Batteries
For the science of, the advantages of, the problems with, the history of, and future of
the various types of Lithium-ion" battery I suggest those of you interested in delving further into it refer to :
Li-ion batteries on Battery University
Li-ion polymer batteries on Battery University
LiFePO4 Li-ion batteries on Battery University
Taking Care of a Lithium Battery?
The lithium battery is the most expensive part of your electric bicycle.
It is very worth while your taking good care of it. It will have its own built in Battery Management System
that should protect it against its being short circuited, its overheating, or cells within it that don't
do their equal share of taking a charged and giving it back. The BMS is not a 100% guardian.
They should not be overcharged. The charger should power down when the battery is charged, but if the
charger indicates "charged" disconnect it anyway. Leaving chargers "on" will reduce their life in any case.
The charger should turn off when the current is low.
Note also that 36 volt battery chargers are NOT all the same. Do not use one meant for a lead-acid battery
to charge a li-ion battery, or LithiumIronPhosphate or vice versa.
LiFePO4 batteries are charged at a slightly higher voltage than Li-ion batteries (43.8v vs 42v) and
should have a charger meant for LiFePO4 batteries. A "LiIronPhosphate" charger will overcharge a Li-ion battery
The batteries will age quicker when fully, or nearly, charged. The more time they spend fully charged the less will
be their life. If the bike is not going to be used soon then leave charging until soon before you expect to use it.
Also frequent topping up is not recommended for similar reason. The power from the battery is quite constant
until about 70% of the energy is used. It's a misconception that a full battery gives more power.
Li-ion batteries do not have a memory effect. You don't want to risk running the battery flat, but if your
use is generally short trips then it is best to go around 2/3 of battery range before recharging.
Temperature extremes have a big effect on life of a battery. The life reduces more if used above 50degC or below 10degC.
They should not be left in sun, or stored in a hot place.
If it has been in sun or hot place allow it to cool before use.
Parking your bike in a place with full sun every day will be the greatest factor in reducing the life of the battery.
The battery ages more slowly if stored in a cool place, even in refrigerator
(not freezer), but then do allow it to warm up before use.
Your battery should not be left unused unrecharged for more than a few months,
lest the constant trickle of current used by the battery's management system take the voltage down to a critical level.
However they should also not be left for a long time fully charged either as that too reduces life. About half charged is better.
There is a much misinformation about "li-ion" batteries. To be better informed follow the links above.
What if it raining? Is that a problem?
No more so than with any bike. The electrics are sealed and water runs off the battery and motor.
Of course one has to be careful with wet roads but puddles or wet roads are not a problem
because the bike is electric. Just avoid deep water, and leaving the bicycle out in the rain
I see some have gears, some do not. Are gears necessary?
In a word, no. As mentioned above, the new electric motors are "clever" in that
they sense how much power is needed, and apply more torque as necessary, and, unlike older motors,
can deliver power efficiently over a wide speed range.
With the bikes with a hand throttle you turn up or down the power as you choose.
With 200 watts of power you only need to assist the motor on medium hills.
Even without gears you won't have to stand up and push, for a start, or going up hill,
like you may have had to do on an older non-electric bike without gears.
Nevertheless most of my e-bikes have gears so that when you need to assist the motor
going uphill it will be easier with the low gears
If comparing, with or without, having set of Shimano gears may add about $40 to the cost.
Why is there such variation in the cost of different bicycles?
3 things make most of this difference
1. Aluminium alloy frames are much more expensive and magnesium alloy even more.
2. Lithium-ion batteries are about 3 times the price of lead-acid ones. $350 vs $120
3. 36V, and the higher AH versions, are more expensive than the 24V batteries,
(especially so for lithium-ion batteries).
Having derailleur gears, especially Shimano, adds significantly.
Other extras such as lights, baskets, carry racks, a good soft seat also make some difference.
Look at these things when comparing. A 36V alloy e-bike with lithium battery could be about
twice the cost of a 24V steel e-bike with lead acid battery and similar frame.
With so many variations on offer it can be confusing comparing.
How heavy? how light?
It's simply cost vs weight.
Alloy electric bicycles with lithium batteries can be as low as 20Kg
while steel electric bicycles with lead batteries can be up 48kg.
A 6volt SLA battery is about 14kg and a 36 volt lithium battery is about 4kg.
The two factors to gain or lose weight are the battery and the metal of the frame.
Also some frame configurations plus add-ons are inherently heavier.
To save 10 or more kg with lithium instead of lead for batteries, or to save 5 or more kg with alloy
instead of steel for frame are roughly equivalent at about $25 per kg saved.
Most models available from many suppliers go for both the light options or both the heavy options.
There are very few taking the middle path compromise.
I do have an "in between" model - one that's halfway lighter because it has an alloy frame,
and halfway cheaper because it has lead-acid battery.
Considering that you together with the bicycle weigh about 100kg (give or take a few kg)
20 kg saved with the lightweight e-bike is comparatively minor in an overall sense...
but could be important if your route, or tracks, are hilly, or if you need to carry your e-bike
any distance, especially up steps, or on the train/bus.
Incidentally, a good alloy frame bicycle will be expensive in any case,
and having it with an electric motor is then a relatively small extra cost.
If you want more exercise by not using the motor then it is easy to remove a battery
What is the law for electric bicycles?
In Australia any bike can be electrically assisted up to 200W and not require
license or registration. (For most of rest of world that is 250W, and for US it is 750W).
The same rules apply as for any bicycle. Take the same care, go the same places.
Electrically assisted bicycles "capable of" more than 200W require registration as a moped
(even though they have pedals) and in any case are unlikely to satisfy the
Australian Design Rules to qualify for registration in order to be used on roads.
I supply some models or kits with 350W motors for use off road where permitted.
It's similar for electric pavement scooters for recreational use. Power up to 200W is considered
a pedestrian - and one who should apply the same care as a normal unpowered skater.
Electric bicycles (2 or 3 wheels) over 200W and with a maximum speed of 50 kmh or less
are considered mopeds. These need to be registered as such, but can be driven with a car license.
If capable of speed over 50kph they are motor bikes, and need to be registered and licensed
as such. Electric mobility, ATV, and golf carts have same legal requirements as fuel powered ones.
What is the cost of running?
The power cost is small...36Vx10AH is about 0.4 of one KWh, and your electricity
supplier sells you 1 KWh for about 22c. A full recharge is therefore about 8 cents or about 0.2c/km
It is not often mentioned but if used often the bigger cost would be the eventual cost of replacing
the batteries. A lead battery will last 10 to 12,000km, or about 0.9c/km
and the lithium batteries about 35 to 40,000km, again about 0.9c/km.
There are ways for extending the life of a battery. (See above)
What benefits are there in having an e-bike?
1. To you, your health, your fitness, your weight, your convenience, and the cost saving
2. To your environment, a lot less CO2 in the air, and more fuel staying in the ground
It's a cost saving option
At one cent per kilometre it's a tiny fraction of the cost of driving a car.
(Fuel cost $1.43 for 13km = 11c/km, depreciation $3000/20000km = 15c/km)
(An occasional taxi, and rented car cost a lot less than owning a car).
And all those short public transport trips? They add up!
In most cities typically any ride, even a short ride, is about $3.40.
It's the healthy option
Because an e-bike is much easier to ride than other bikes you are much more likely to actually ride it,
and do so more often, even regularly, and so, be healthier, and get fit, for almost free.
it's the greener option
E-bixe are a very environmentally friendly solution, especially if otherwise, you would use a car.
The CO2 from you riding along (plus some more at the power station to do the recharge)
is less than 1000th of the CO2 and other stuff coming out of a typical car.
And that's not allowing for all the extra cost of all the engineering for the whole road system.
It's so much the better if you eliminate or reduce the commute and small trips you make with a car.
Perhaps you can do without the 2nd car in the family, as a start.
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