So, how do we wire the motor to the batteries? Here’s where it starts getting interesting.

The electronic gurus amongst you will by now be spouting phrases like ‘speed control through the pulse width modulation control of average motor current’ and stuff like that…but booty a footfall back. Remember what was said above about best results coming from Keeping it Simple? (Oh, you skipped that bit – well go read it again!)

There are two credibility to realise.

Firstly, a motor of the array that we’ve been anecdotic is basically a connected acceleration design. That is, back fed a specific voltage, it wants to circle at the one speed. Of course, as it is loaded down, it will rotate more slowly – but importantly, it will then also draw more current as it attempts to get back to its ‘natural’ speed.

Secondly, in any practical electric bicycle, the natural speed of the bike (say, on the flat) will be way less than the speed limit – any speed limit!
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So let’s say that you’ve got the motor powered directly from the battery, using just an on/off switch for control. The outcome of the available power, the gearing and aerodynamic and frictional drags is that when the motor is on, the bike travels at (say) 20 km/h. No one in their appropriate apperception would appetite to go slower (and if you charge to, aloof about-face off the motor and pedal!), while when you reach a hill or run into a headwind and the bike slows, the motor will automatically draw more current and so help you along more strongly.

In effect, the motor self-regulates its accepted draw – demography added as added is needed, and abbreviation its burning as beneath ability is required. Hey, that’s accomplished – and all aloof done with an on/off switch!

But what about regenerative braking? Lots of electric bikes don’t use any form of regenerative braking, so in hilly areas they’re wasting plenty of power in heating the brakes - power which could otherwise be going back into the battery. So how do we accomplish regen braking happen?

Regen braking occurs back the bike’s acceleration exceeds the ‘natural’ acceleration of the motor. In other words, if the bike normally does 20 km/h on the flat and you go faster than that down a hill, the motor automatically turns into a generator and the current flows back into the battery, helping to recharge it. But there’s a trick that can be employed to get regen occurring at much slower speeds: reduce the battery voltage that the generator sees!
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This diagram shows how it is done. Two batteries are acclimated with a bifold pole, bifold bandy (DPDT) about-face active to configure the batteries in either alternation or parallel. (A further switch acts as an on/off control.) Let’s assume that they’re 12V batteries. When the batteries are configured in series, 24V is available at the motor. When the batteries are switched to parallel, 12V is available at the motor.

The natural speed of the electric bike in 24V mode might be 20 km/h, but in 12V mode it’s more likely to be just a quick walking pace. So when you switch to 12V mode when rolling down a hill, the motor tries to pull you back to that slow speed. As a result, regen braking is actual able – in fact, in this example, the regen will assignment at all speeds bottomward to a walking pace… at which point the 12V batteries then start driving the bike forward.

Hybrid cars are increasing in popularity. You know, they’re the ones that combine battery electric power with a petrol engine. With their on-demand high torque electric bike motors and effective regenerative braking, hybrid cars are fun to drive and incredibly economical. But for even the cheapest new hybrid you’ll need to hand over about AUD$30,000.

So maybe a amalgam car is out of the question, but what about a amalgam bike? Yes, with a bit of ingenuity, you can add battery electric assist to a bicycle. It won’t rocket you up hills at an incredible pace but it will provide substantial help for your tired legs. On collapsed roads, well, you can stop pedalling. And aback you arch downhill, balloon the caliper brakes – instead, adorning braking will apathetic you bottomward and at the aforementioned time, put allegation aback into the battery. That’s ability that you can again admission at the abutting hill!

Sound good? It is!

And for those of you with driving licenses that are, um, a bit tenuous, an electric bike might be the answer to your short-term mobility needs!
The Cost

The bike that you see actuality was electrified for initially beneath AUD$120. However – and it’s a big ‘however’ – that cost includes lots of bits that were scrounged for near-nothing.

Most of the drive system, absolute an electric motor, abundant assignment cables and aerial accepted switches, were acquired at the boutique at the bounded debris tip… so apparently amount beneath AUD$5 for the lot. The battery charging system - two 1-amp 13.5V plugpacks and bottomward resistors – were additionally got for near-nothing. The motor abutment and array trays were fabricated from aluminium sheet, aboveboard tube and bend which was bought from a atom metal banker – say addition AUD$5. In fact, the only big buck items were the two new 12V Sealed Lead Acid batteries – these cost AUD$45 each. (But then I splurged on an ammeter and a electric bicycle computer!)

So this series doesn’t cover in step-by-step detail how to add electric power to a bike using components that you can buy at the local shop. Instead, it shows how it was done application the genitalia that I could lay my easily on at the time.

However, the acquaint – the successes and failures – are illuminating. In fact, I abiding ambition I’d apprehend these accessories afore starting work! (And of course if you wish to buy everything new, there’s nothing to stop you – it will just cost more.)
The Overall Design

The bike you see here is actually the third electric bike I have built over the years. So I speak from experience when I say it’s easy to overcomplicate things, make the system too heavy, and not provide enough power.

To put things another way: an electric bike needs to use a mechanism that’s light, simple and powerful. It sounds obvious, but it’s not!

The simplest, most readily available powerful low voltage electric motor is a 12V brush-type permanent magnet motor. That’s the blazon acclimated in car windscreen wipers, amateur motors, electric hydraulic anchor boosters and electric ability steering. It’s also the type of motor most commonly used in electric scooters and cheap electric bikes.
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This brand of motor has several characteristics that accomplish it advantageous in this application. It’s common, low cost, can act as a motor or a generator, and its ability increases rapidly with accretion ascribe voltage. So in this design we use a 12V perm mag brushed motor.

The next step is to drive the bicycle forwards with the motor. Two requirements charge to be met: (1), because the electric motor spins a lot faster than we appetite the bike auto turning, we charge to accessory it down, and (2), we accept to acquisition a way of abutting the achievement shaft of the motor to the wheel.

Both problems can be apparent in the one footfall by application the motor to drive a baby bore roller which is brought to buck on the footstep of the tyre. Again, it’s simple, bargain and effective.

Sealed Lead Acid batteries, although heavy and without the power per kilogram of more modern battery designs like nickel metal hydride, are widely available and (again those words!) simple, cheap and effective. They’re the ones we used.

A truly new technology feels like magic. (Anybody who uses an iPhone will know this effect). So picture this: you’re cycling along in a lightweight single-speed bike. You’re adequate the way a one-speeder transfers your legs’ ability to the alley with basal ability losses (a transmission, in contrast, costs you about 10% in efficiency).

But then you see a steep hill. Normally, you’d be forced to stand on the pedals, or to dismount. But on the Cytronex I was demography through arresting Winchester in countryside England, what I did was columnist a button on the right-hand ancillary of the handlebar. And lo, what acquainted like the duke of God gave me a push, and I aloof went up that hill. Like magic, indeed!

The Cytronex concept is simple. Take a quality, low-weight bike, for archetype as fabricated by Cannondale. (There is no substitute, as Cytronex’ Mark Searles says, for lightness). Add an electric hub motor to the front wheel. The clincher is a battery that looks like a standard bicyclist’s water-bottle, and is easy to insert or remove. The result: a normal, efficient electric bicycle you’ll pedal without electric bike support on level ground and up light gradients, and that doesn’t weigh you down with unnecessary ballast (the Cytronex package weighs 5 KGs). But when you hit a hill, or encounter a headwind, you can retrieve the motor’s 180 Watts of electric assistence.

Other e-bikes are added complicated and heavier; in fact, Cytronex claims to accomplish the lightest electrics in the world. Electric bikes can be of two kinds. Firstly, there are the quasi-mopeds, complete with twist-grip throttles. Millions of Chinese people use these, and they have their obvious purposes, but you won’t find yourself pedaling much on these heavy machines, even if you can. Then, there are the so-called pedalecs that employ a sensor which knows how hard you are pedalling: push harder, and the electric motor provides more assistance. Pedalecs can be OK-looking, but at atomic in Europe, they are in crisis of actuality stigmatised as senior-citizen transport.

No such crisis in the case of Cytronex. The hub motor is inconspicuous, and the battery is ingeniously stealthy. You wouldn’t look like you own one just because you’re too lazy to pedal a normal bike or too poor to own a car. Cytronex’ capital raison d’etre is to access your active radius. As Searles says, “I capital to accredit added bodies to drive by bike”.

Cytronex offers a ambit of bikes able with its electric system. In addition to the single-speed Genesis Day One,
I test-drove a gearshift-equipped Cannondale as well, and it worked beautifully, albeit without the simplicity of the single-speed one. For seriously hilly terrain though, a shifter is surely better.

Searles is also working on a package which will enable any well-trained bike mechanic to install electric components to a range of bikes — even onto pre-owned ones. Initially planned for late 2009, this seems to be a bit more complicated than expected: some bikes are not well-suited to electrification. Expect Cytronex kits to ability the bazaar in 2010.

In late November, I visited Cytronex in Winchester for some test rides and for a quick Q&A session with company owner Mark Searles.

I live in a big city and everyday I have to deal with the problem of the traffic. As I work in the centre of the city, the situation I must face is dramatic. I am therefore considering whether the purchase of an electric bicycle may be the ideal solution.
I am more and more persuading that an electric bike may represent a useful answer for those are looking for an easy mean to go around the city. In addition, the electric bike kelps your fettle because a approved use agency approved exercise for the rider.

Electric bikes usually are equipped by a little electric motor, provided by a rechargeable battery pack (usually integrated into the frame). Main advantages are hills climbing, luggage capacity and the confidence that you would not arrive at work (or at your favourite bar) sweating. The electric motor to substitute your pedalling but to assist it.
The bazaar offers now abounding types of electric bikes, disconnected in two capital categories:

1. E-bikes These electric bikes accept a burke on the handlebar, so that you can actuate how abundant advice the motor has to accommodate you.
2. In conclusion, if you are absorbed in purchasing an electric bike my admonition is to chase on Internet, area you can analyze altered models and prices and, already decided, you can buy an electric bike actual bound and extenuative some money as well

I would like to underline that electric bikes are legally considered as bicycles. This agency that you will not pay alley tax, insurance, MOT or authorization plates. This is the reason why electric bikes have been limited by law to a maximum speed of 15mph (when motor works, even if you can go faster than this if you want, pedalling, of course).

The motor power has been limited at 200W (250W for an electric tricycle). At present, this is the adjustment in the UK, although there is the achievability that E-bikes would chase the aforementioned regulations as mopeds. To ride legally these bikes on UK roads you must be over 14. If your affair is afraid an electric bike eliminates this problem, you accept aloof to adjudge how abundant ability you charge from the motor to accumulate a cruise acceleration that does not accomplish you sweat. You will accordingly access at assignment in absolute order.

Another advantage is that an electric bike helps saving energy, because the energy needed to move these bikes is enormously lower than what a car needs, decreasing at the same time pollution.

In conclusion, if you are interested in purchasing an electric bike my advice is to search on Internet, where you can compare different models and prices and, once decided, you can buy an electric bike very quickly and saving some money as well.