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Tag: ebikes

Folding Electric Bikes Are Brilliant. Here’s Why

There’s never been a better time to get a folding electric bike. As a cost-effective, eco-friendly, and convenient mode of transportation, they’re perfectly suited to urban living. In this post, you’ll see how much better a folding e-bike makes it to commute, run errands, and generally get around town.


Getting Around Town Is No Sweat

Riding an electric bike is a great way to burn off excess calories without breaking a sweat. Pedal away as much as you want to get your heart pumping; when you need to take a break, simply let the electric motor do the work. You’ll especially appreciate this every time you commute or ride to a social event as you won’t need to shower or change clothes when you arrive at your destination.





You’ll Be Riding Up That Hill With No Problems

You shouldn’t have to choose between struggling to pedal up a hill as your legs and lungs beg you for mercy or getting off and walking your bike up, which can be a hassle in itself. Your e-bike’s motor can power you up hills; you’ll also have a less strenuous ride when you’re carrying your rucksack, bags of groceries, or anything else you need to transport by bike.




Get Up To Speed Easily

There are times you need to accelerate from a dead stop quickly to keep up with traffic, both on roads and bike lanes. Your folding e-bike’s motor takes care of this for you instantly, giving you added peace of mind at intersections. Additional power can also benefit you when you need to overtake – just as long as you’re doing so with total awareness of what’s going on around you. After all, with extra speed comes extra responsibility!





How Convenient

Lightweight and foldable, yet incredibly durable, folding electric bikes are easy to store and carry. If you need to use public transport during your travels through town, you can quickly fold up your e-bike and carry it on with you. Because it takes up no more room than a large piece of luggage, your folding electric bike is far less of a bother to transport than a regular bike. 

When you get to your destination, you can keep your bike with you and store it without obstructing others. This beats locking it outside or putting it somewhere that’s going to annoy the people you live or work with. Since you can store your foldable electric bike indoors, you don’t need to worry about bike thieves taking off with your ride – in essence, your bike comes with a built-in security system. 




No Room Too Small

For the growing number of people living in micro-homes, storage space is a serious issue. No matter how small or big your home may be, folding electric bikes help you maximize your available space. You can store it pretty much anywhere – in a closet or corner, under a table or bed, or on a balcony or a hook in the foyer.



This advantage extends to car storage – when you want to take your e-bike with you on a road trip, fold it up and pop it in the boot. You no longer have the hassle of affixing your bike to a roof rack or folding down the back seat to fit your bike into your car. Bringing your own foldable electric bike also spares you the expense and risks of renting a bike during your travels.






Become An Eco-Road Warrior

Well, maybe not a warrior, we just like the way that sounds. The point here is that more bike riders mean less air pollution. Folding electric bikes are as environmentally friendly to ride as push-pedal bikes. They also happen to be a convenient, healthy, and fun way to get around.




Explore Your Options

To get a better idea of how much a folding electric bike can bring to your life, check out our Furo X. This popular e-bike fuses style, performance, and practicality – plus an abundance of extra features – to give you a riding experience that experts are raving about. If you’re looking for something that’s even lighter but still a dream to ride, take a look at our eTura.


We’re always available to answer your questions and help you choose the right folding electric bike for your needs, so get in touch with us.

Coronavirus Chaos: How to move around London without risk

The coronavirus pandemic has thrown the world into disarray. In the UK, as elsewhere, the government has placed severe restrictions on movement. Restaurants, cafes, bars, cinemas, and just about any other location where gatherings could potentially take place have been closed down, whilst home working has been recommended for all but a handful of ‘key workers’.  


The message from Prime Minister Boris Johnson is loud and clear –’Stay at home’. If you happen to be one of these key workers, however, you may be left wondering how you can get to work without the risk of picking up or spreading coronavirus. 


The latest reports from London show that tubes and trains are still packed during rush hour – perfect conditions for this disease to pass from person to person. As fewer services are running and stations closed, those who do have to travel around the capital (and many that don’t) are cramming into carriages. 


In order to prevent the spread of this disease and the NHS from being overwhelmed, two things need to happen: firstly, we repeat, stay at home; secondly, seek other ways of moving around the capital that are less risky. 


As it happens, we might just know the ideal alternative to the tube during this troubled time. 


electric bike london


Pedalling against the pandemic 

If you’re a key worker, one of the most secure ways to avoid contracting or spreading COVID-19 on your commute is by getting on a bike. Now, you could use a standard old-fashioned bike, but this pandemic has caught you unaware and you might not be in the best shape to pedal across the capital. An eBike is the answer, and here’s why. 


  • Motor-assistance – Electric bikes are fitted with lithium-battery-powered motors that assist you up to a maximum speed of 15.5 mph. This means you can get to your workplace without breaking a sweat, and probably faster than you would with the tube anyway. 
  • Sustainability – Electric bikes are an environmentally-friendly way of getting around. Whilst pollution has plummeted in London since the beginning of the outbreak, riding an eBike certainly won’t dirty the capital’s air. 
  • Reliable – TfL has closed more than 40 stations around London and reduced most services to a weekend rota. Although it’s committed to ensuring key workers are able to reach their destinations, travel is likely to be disrupted. With an electric bike, however, commuters can take control and be where they need to without delays. 


Cycling during Coronavirus

Cyclists must adhere to the normal rules when cycling during Coronavirus outbreak. This includes regularly washing hands, not touching your face, and severely limiting social contact. Specific consideration for cyclists is to be wary of touching handlebars, helmets, and any other equipment. Preliminary research has shown that the virus can live on surfaces from anywhere between a few hours to days, so it’s highly advisable to wash your hands as soon as you’ve finished your ride to your workplace or home. 


Everyone must do what they can to stop the spread of coronavirus. For most, this means staying inside and avoiding all but the most essential contact with people from other households. For others, especially those deemed as ‘key workers’, this means reducing the risk of contracting and spreading the virus. Alongside thorough hygiene practices, choosing alternative modes of travel like an electric bike will help to stop the spread of this disease. 


FuroSystems make a range of electric bikes to aeronautical design precision. Our eBikes offer commuters a fast, efficient, and green way to travel to-and-fro. Check out theFuro X – the first ever full-carbon folding electric bike. 

Are Ebikes the future of personal transport?

Electric bikes continue to go from strength to strength. In many modern cities, it’s almost impossible to go a whole day without seeing one. Whether they are privately owned or public bike-sharing services, it’s hard to ignore their recent surge. The question is, are electric bikes just a fad or can they become the future of personal transport for the masses? It’s an important question and one that we think we have the answer to. Ebikes have perhaps the most potential of any type of vehicle for providing a long-term solution to individual travel. In this article, we discuss exactly why ebikes are the future of personal transportation. 


Current trends

Globally, demand for ebikes has grown exponentially. In the US alone, ebike sales have increased eightfold since 2014 and this trend shows no signs of slowing down. One reason for this is a change in attitudes towards cycling more generally. Cycle lanes and routes are being built all over the world, and in the UK they’re being installed and used at an ever-increasing rate. In London, for example, two-cycle superhighways were opened in 2016. Since opening, use of these highways has increased by 200%, and cycling overall has increased in London by 152% since 2000 – it’s the fastest-growing mode of transport in the capital. Similar stories can be found in all major cities across the country. 

Another demonstration of this growing trend and a sign that it’s here to stay is the rise of bike-sharing services. Dockless ebikes are being spotted all across London, with the most popular companies being JUMP by Uber, Lime, and Mobike. These services allow you to hire electric bikes using your phone and leave them (within reason) anywhere once you’ve completed your journey. It’s similar to the popular Santander Cycles but has the benefit of being electronically assisted and not having to find a docking station. They’re popular in a number of other European cities and have made their way over to the UK. Investment in these services on such a scale shows confidence in the strength of this industry and will only help ebiking to be more accessible. 


City transport needs

Is this the future of personal transport in big cities? The biggest reason for the aforementioned trend is that electric bikes meet a real and pressing need that city-dwellers have. Air pollution is a huge problem for the world’s urban areas and busy roads full of cars are a major contributor. What’s needed is an emission-free, sustainable form of personal transport which can reduce our dependence on travelling by car. Enter ebikes: a fast, affordable, and emission-free mode of personal transportation. 

Even cities and countries that have long been huge proponents of traditional cycling have recognised the benefits of electric bikes. The Netherlands, for example, the most bike-friendly country in the world, has seen a surge in ebike popularity. One in three new bikes purchased in The Netherlands in 2019 was electric, it’s reported that 40% of ebike riders have chosen their ebike over their cars as a way to get around. 

Colorado Springs in the US is a city that’s investing heavily in electric bikes. Government officials and private companies are working together to make Colorado Springs as Smart, sustainable, and mobile as possible and electric bikes are a favoured option. 

The size and average range of electric bikes make them the perfect vehicle for travelling around a city. Our Furo X electric bike, for example, has a range of approximately 45-55km (28-34 miles) which is ideal for a day out in the city. For shorter journeys, you’ll likely walk or perhaps take an electric scooter (if your city permits them), and for longer journeys, you’re likely to favour a car or train. For commuting and making trips across a city, electric bikes are the perfect medium. 



It’s hard to deny that cycling – whether electronically assisted or not – is great for our health (and far better than sitting in a car). The advantage that ebikes have over traditional bikes, and a reason they have such huge potential to become a widespread mode of transport, is because of their inclusivity. Traditional cycling is for those who are fit and able to ride, whereas electric bikes provide assistance to riders, making every journey easier than it otherwise would be. Even the fittest cyclists often dread going uphill, but electric bikes solve this problem by taking the strain for you. 

Ebikes lower the barriers to entry, allowing those who would typically be unable to ride a bike (especially in a city environment) to enjoy the benefits of cycling. Some studies suggest that regular cycling has a positive impact on those suffering from diseases such as Alzheimer’s and Parkinson’s. Ebikes offer a realistic way for older people to exercise and minimise the impact of these debilitating diseases. As we become a more health-conscious society, modes of transport that involve some form of exercise will trump more sedentary modes. 

Electric bikes are going to play an increasingly large role in the way we get around and how the future of personal transport is evolving. Join the growing trend by getting your very own electric bike: our Furo X is one of the most powerful ebikes on the market, offering great riding comfort and state-of-the-art folding design. Perhaps you’d like something a little smaller and easier to carry with you – our Etura is the lightest folding electric bike you can buy. Weighing just 12kg, it’s ideal for carrying on and off trains or leaving by your desk at the office. If you have any questions about electric bikes, please get in touch with our friendly team. We’d love to help you kickstart your ebike journey! 

Electric Bikes vs Motorcycles: 5 Differences

With electric bikes becoming more and more popular, they naturally invite comparison between them and motorcycles, both electric and petrol, and it’s understandable. There are powered bikes that are often used for commuting and whizzing around cities. If you own a motorbike already, is it worth investing in an electric bike? In this article, we discuss the major differences between electric bikes and motorcycles in a range of areas.

Before we start, it’s important to establish the key difference between electric bikes and motorcycles: the way you ride them. With electric bikes, you pedal just like a traditional pushbike, and then the electric motor provides you with assistance. With motorcycles, there’s no pedalling involved, and all movement is controlled by the throttle. The differences don’t end there.



1. Legal requirements

Electric bikes and motorcycles are treated very differently in the eyes of the law. motorcycles, whether electric or petrol, are liable for road tax, insurance, and must be registered with the DVLA. Riders of motorcycles must also have a driver’s licence to be able to legally drive the vehicle. With electric bikes, no such restrictions apply. You do not need a driver’s licence, the bike doesn’t need to be registered or insured, and you don’t need to pay tax. In the eyes of the law, electric bikes are generally treated the same as traditional pedal bikes.

The clothing riders must wear differs between motorcycles and electric bikes too. Motorcycle riders are required by law to wear a crash helmet at all times, and it’s advisable to wear more protective clothing. The higher speeds that motorcycles are capable of come with a higher risk of injury. When riding electric bikes, you do not need to wear a crash helmet (although wearing a helmet of some kind is strongly advised). You also don’t need to carry around cumbersome motorcycle outfits. Electric bikes give you the freedom to wear whatever you want, within reason.

That being said, wearing protective clothing is recommended, especially if you’re going to be taking your electric bike onto busy roads. Read more about the legality of electric bikes in our dedicated article here.



2. Speed

It should come as no surprise, but electric bikes cannot compete with motorcycles (electric or petrol) when it comes to speed. The primary factor is regulation that limits the speed at which electric bikes will provide the rider with assistance: electric bikes are required by law to stop providing power when the bike reaches a speed of 15.5mph (25kph).

Motorcycles, on the other hand, do not face such limitations and are legally allowed to reach much higher speeds. If you’re a speed demon, then a motorcycle, either electric or petrol, may be best for you. However, as you’ll see in the next section, being able to travel faster doesn’t necessarily mean you’ll reach your destination sooner.



3. Commuting 

Electric bikes make for a perfect commuter vehicle. They’re light, fast, reliable, and not subject to train delays!

In a city, the added speed capabilities of a motorcycle are irrelevant because of rush hour traffic and traffic lights. Electric bikes share the advantage that motorcycles have over cars in that they’re able to sidle down the side of traffic. However, electric bikes have the added benefit of being able to use them in cycle lanes and in certain parks around cities. You have more travel options with an electric bike. Motorcycles are restricted to roads. Therefore, in reality, the faster vehicle isn’t necessarily the fastest method of commuting.

Furthermore, electric bikes have a number of other practical advantages over motorcycles. For instance, there’s no need for a parking space, and many offices have space for bikes to be locked away safely. Also, some electric bikes, such as our very our Furo X and eTura, can be folded. Folding electric bikes are even more versatile since you can carry them onto trains and buses, and you can even take them into coffee shops or store them under your desk at work. Every base is covered!



4. Maintenance

Electric bikes come with far fewer maintenance needs than traditional motorcycles. There’s no oil or cooling system to take care of, and there are fewer parts overall, meaning there’s less to maintain. Additionally, running costs are minimal in comparison to petrol and electric motorcycles. You don’t need to buy any fuel, and you don’t need to charge the bike either. Electric bikes are ready to use at all times – there’s no preparation or forethought needed. When the mood takes you, you can hop on and be on your way!



5. Exercise 

By virtue of needing to pedal in order to move, electric bikes are far better from an exercise perspective. Of course, electric bikes offer a huge amount of assistance to the rider, which makes them so enjoyable and accessible, but there’s still an element of rider input beyond twisting a throttle. For people who find traditional cycling very taxing – especially in a city – electric bikes offer an accessible form of exercise that motorcycles simply can’t.

While we may be a little biased, in many cases, electric bikes are the more versatile form of transport. They can be used in more places and by more people than motorcycles, and that’s a huge plus in a world that’s constantly looking for new and improved modes of personal transport. If you’ve been thinking about investing in an electric bike, check out our eTura, the lightest folding electric bike you can buy, or our ever-popular Furo X, the electric bike that started it all.

The Furo X is sold out for delivery in May and 10 days left for 25% DISCOUNT

Taking our bikes from paper directly to you and making them your new favorite way of commuting, cycling or just having fun has truly been a formidable adventure and keeps getting better!The FURO community is growing day after day and we have officially just sold out our batch of FX for delivery in May. The SIERRA is almost gone as well with only 2 left in stock.

As most of you are aware, our 25% discount is also ending very soon. You can rest assured that it still applies to all purchases made through our website until it expires. This means that our next batch of SIERRA and FX is still covered by the discount until the 15/05. It is currently planned for delivery in September, although it will most likely come earlier than this as we are working very hard to accelerate our production rate and optimise our supply chain.

If you are thinking about getting a FX or a SIERRA, we strongly advise to make the most of the discount, particularly as our next batch will also have a limited stock.

We are always available and very happy to help you, so if you have any questions or requests please don’t hesitate to contact us.

The Physics Behind Electric Bikes Through Numbers

Our stock of FX and SIERRA for delivery in May has almost run out, and that is a lot earlier than we anticipated. You guys are loving it and to celebrate that, we are going to give you a short but complete article on the physics governing your ebikes rides.Let’s start with the protagonist itself, the ebike, here we will have a look at the SIERRA in particular. The SIERRA is made of a full carbon frame which has to be structurally strong enough to support the sum of your weight, the ebike’s weight with all its components, and the weight multiplication and shocks due to bumps and other obstacles on the road. In addition to all the typical bicycle equipment (disk brakes, gears, chain pedals, wheels, etc) the SIERRA’s frame also has to carry a motor, a battery, an electronic controller and a computer. These components are all relatively heavy with respect to the frame of the bike but remain light once you add your weight to the equation, even for the skinniest of you.

SIERRA Configuration

The SIERRA is equipped with a torque sensor which measures how much pressure you are exerting on the pedals. In turn, it sends a message to the controller which calculates how much power from the motor is immediately required. At the same time, the computer scales the controller’s calculations with respect to the assist level you are set on. Eventually, the controller which is connected to the battery opens a channel between the battery and the motor and allows high power currents to flow in a certain pattern so as to activate the motor and power your ride.

This then makes you go forward and pick-up speed. We will now focus on what is happening once you have reached a speed of 20km/h and are accelerating by 1km/h per second or reaching 25km/h after 5 seconds on a flat asphalt road. According to the second law of Newton, all the forces acting on the bike and yourself while you move forward are equal to your total mass multiplied by your acceleration. This can be written:

with F the sum of the forces in Newtons, m the total mass in kgs and your acceleration in m/s².

Sir Isaac Newton

The forces acting on the bike and yourself while you are moving are:

  • Your own applied through the back wheel of the SIERRA: we will call it Fy and it is measured in Newton
  • The motor’s applied through the back wheel and the chain of the SIERRA: we will call it Fm and it is in Newton
  • The aerodynamic drag, due to your movement through the air of the atmosphere, which can be calculated in Newton using the following equation:
    with Cd the coefficient of drag, p the density of the air, V your velocity and A your frontal area.
  • The rolling resistance of the tyres on the road which can be calculated in Newton using:
    with Cf the rolling resistance coefficient of the tyres on the road, m your mass in kg and g the gravitational constant g=9.81m/s², m*g is essentially the force in Newton exerted downwards by your weight on the bike.

FuroSystems SIERRA Sum of Forces

First of all, we can calculate the drag. In a standard relaxed cycling position on the SIERRA, your frontal area is likely to be 0.6m² and your coefficient of drag: 1.15. The density of the air at sea level is 1.225 kg/m3 and your velocity is 20km/h which is equivalent to 5.6 m/s.

So we get: D = 0.5 * 1.15 * 1.225 * 5.6² * 0.6 = 13 N.
The rolling resistance coefficient of bicycle tyres on asphalt is equal to 0.004, assuming you are 75kgs, the weight of the SIERRA being 20kgs, your total weight becomes 95kgs.

Hence, your rolling resistance is Fr = 0.004*95 = 0.38 N.
So the sum of the forces can now be written:

Fy + Fm – D – Fr = m*a

with m your total weight (95kgs) and your accelerations in m/s².

Also, note that the sign of the forces in the sum depends on the direction these forces are acting. If they act in the direction of the movement, then they are positive, if they act in the opposite direction, they are negative. We can replace the variable with the values we calculated knowing that an acceleration of 1km/h/s is equivalent to 0.28 m/s²:

Fy + Fm – 13 – 0.38 = 95 * 0.28 which is equivalent to Fy + Fm = 40 N
We know that the wheels of the SIERRA measure about 0.70m in diameter and therefore 0.35m in radius. We also know that torque is a force multiplied by a distance. Hence, the torque generated by the combined efforts of your legs and the SIERRA’s motor is 40*0.35=14 Nm. We can even get the total power by multiplying this by the angular velocity of the wheel, or the speed at which it rotates. We know that its perimeter is 2 * PI * Radius = 2.2m. As we are going at 5.6m/s, this gives 2.5 rotations of the wheels per second or an angular velocity of 15 rad/s (multiply by 2 * PI).

Hence, on a flat asphalt road, in order to maintain an acceleration of 1 km/h per second while being at a velocity of 20km/h, the total power needed from you and the SIERRA together is 15*14= 210W.

As the BOFEILI mid-motor of the SIERRA produces 350W of continuous power and more than 600W of peak power, at this cadence you will only be exploiting a third of the power of the beast. Depending on your assist level, you can either fully provide the 210W through your legs or entirely rely on the SIERRA, it’s your choice and that is the magic of electric cycling!

Do not hesitate to ask questions in the comments, we will be happy to answer them if anything needs to be made clearer!

First batch shipment and end of preorders

It’s official! Our first production batch is currently at sea and will reach our European warehouse around the 15th of May. We will then unload our containers and ship your bikes to you at lightning speeds, you will receive them within 2-3 days.It’s been a great adventure getting our bikes from paper right to your home and we are pretty sure that you won’t be disappointed! This also marks the end of pre-orders for the FX and the SIERRA. On the 15th of May, all 25% pre-order discounts will be discontinued. Our stock is also limited, so for those of you thinking about getting one of our great ebikes, now is the time 😉

Our mission to get commuters and cyclists beautiful, affordable, high performance ebikes is going better than ever, and we will keep working to get you the best, always!
Thank you all for your support!

Why an eBike is so good for commuting

This is going to sound cliché, but FuroSystems genuinely started from the following thought: what are some of the biggest problems in our society right now? And can the latest technologies combined with clever engineering solve them?The global population is growing which with urbanisation is causing population densities around cities to increase. In addition, personal transportation systems such as cars, vans and motorcycles are bulky and noisy. Add to that the fact that about a century ago, we chose fossil fuels over electricity (rightly so at the time), we now have a nice combo of polluting, traffic stimulating and impractical vehicles. As this has even become deadly, we urgently need something better.

Traffic Jam

At FuroSystems, we really think that the clear solution is electric bicycles. They are now powerful enough and offer sufficient autonomy to take a rider anywhere, around any city in the world, for multiple days. They are compact, fast, quiet and clean. This is why we decided to use our expertise to help accelerate our society’s transition to this amazing and fun mode of transportation. How? By making them better, more practical, more attractive and more affordable.

As with any great innovation, electric bikes have their sceptics, the main argument is that it’s essentially a way to cheat cycling, something for the lazy.

According to Steve Garidis, the UK’s Bicycle Association’s operations director: “It’s quite difficult to explain what [an ebike] feels like: you’re still cycling but it’s like being an Olympic athlete; you can go faster and longer; hills are less effort. The acceleration is quite fun, even for the most sceptical grown up.”

Happy FuroSystems Electric Bikes Customers

So yes, ebikes do make it easier. They allow older or handicapped people to go places they can’t anymore or never could, and ride with their loved ones. It makes commuting and cycling more manageable. However, they also allow everyone else to experience a new level of acceleration, speed and performance. They don’t remove the effort if you still want it, they just make everything better, more intense, it’s an enhancement of your physical capacities whether you are fit or not. For example, our bikes the SIERRA and the FX give you the option of riding them unpowered making them feel exactly like normal bikes, but they also allow you to multiply your acceleration, uphill capacity and speed, whenever you feel like it. To make it even simpler, they are a 250 W to 600W power add on to your body which you can choose to activate on demand.

Deciding to use an ebike for your commute instead of your car, scooter or moped is probably the best thing you could do today. No more pollution, no more noise, no more fuel, no more insurance and a healthier lifestyle. Folding bikes like the FX are also incredibly more practical, particularly when they are that light while staying very powerful and offering great range, not far off from that of a 50cc petrol scooter.

Electric bicycles are the mode of transportation of the future, they literally solve every single problem you could think of in modern transportation and greatly enhance cycling. In addition, battery technology is close to making significant leaps forward with technologies such as solid-state chemistry, supercapacitors or 2D materials such as graphene. You can trust that we will be here to implement each of these advances in your FuroSystems ebikes as soon they are out!

A little eye candy for those of you that stayed with us to the end 🙂

Electric bike motors explained

To continue our educational series on the physical principles behind electric bicycles, we would now like to talk about how electric bike motors work, more specifically the brushless DC motors that equip your e-bikes. Without those, there would be no sleek and smooth e-bikes like the FX and the SIERRA.

First of all, an electric motor is an electrical to mechanical or electro-mechanical energy convertor. It converts electrical energy to the mechanical movement (rotational or translational). They were first invented by William Sturgeon in 1832, 44 years before Nikolas August Otto created the first practical petrol engine. Our society went to the petrol direction because of the wide availability and the greater energy density of fossil fuels as described in our previous article.

How do e-bike motors really work

First practical electric DC motor

Today, there exist multiple types of electric motors: brushed, brushless, uncommutated, permanent magnet stators and wound stators. Most of these exploit the forces created by magnetic fields and possess some kind of internal mechanism.

Let’s look into the simplest DC motor possible as shown in the picture above. It is made of a stator and a rotor. The stator does not move and is equipped with magnets. The rotor is a coil or armature placed within the stator through which a current passes. This current generates an electromagnetic field aligned with the centre of the coil. The direction and intensity (or magnitude) of this current determines the direction and intensity of the magnetic field produced by the coil. The following picture represents this phenomenon, with I the current. This is also called an electromagnet as it creates a magnetic field when electricity passes through it.

magnetic current through a coil

The magnetic field created in the rotor attracts and repels the magnets placed in the stator (positive pole attracts negative pole and negative pole attracts positive pole). If everything is kept equal the rotor will consequently turn a maximum of 180 degrees before stopping. To keep this rotational motion the poles of the electromagnet that is the rotor have to be switched, guess how? … By switching the direction of the current passing through it as shown in the following animation:

DC motor rotating

DC motor rotating

The question is, how do you switch the current’s direction when your battery is always connected in the same way? Well, in brushed motors, actual conducting brushes make contact with the rotor as it spins and sequentially reverses the current going through it, in turn switching its polarity. However, the obvious problems with using brushing contacts to switch the current are that the whole thing heats up faster and therefore needs a bigger cooling system, it creates sparks, it wears out and consequently limits the speed of the motor.

This is where modern computers and electronics come in. They allowed us to get rid of those brushes to create Brushless DC (BLDC) Motors, the wonderful components that make your favourite electric bicycles possible! Essentially, a BLDC motor is a brushed DC motor turned inside out. The rotor is made with permanent magnets placed in the centre of the motor while electromagnets are placed around it in the stator. A computer, using powerful transistors, then switches the polarity of these electromagnets which leads the rotor to turn. This enhances how well the energy stored in your battery is converted to movement, reduces the need for maintenance and removes the cap on speed as the only limit is now the power available in your system and the speed at which your computer can switch the electromagnets.

Brushless DC motor in electric bicycles

Brushless DC motor in electric bicycles

More specifically, the computer in your e-bike is called a controller and extracts current from your battery in order to switch the electromagnets in the stator of your motor.

Hopefully, this is all kind of clear, if you have any questions, do not hesitate to ask in the comments!

A Guide to Lithium-ion electric bicycle batteries

As we just made the preorders for the bigger battery version of the SIERRA, the SIERRA MAX available, today appeared as a great opportunity to thoroughly explain the fundamental principles and physics behind Lithium-ion batteries and why they currently are the state-of-the-art in electric bikes. When looking at batteries, you basically want to maximise stored energy while minimising volume, weight, and price. As a society, we have been primarily using fossil fuels for personal transportation. This is because this type of power source is really good at storing a lot of energy in a small volume and with low weight while remaining affordable. Now that these chemicals are slowly but surely running out, and we witness how impairing they are to our sustainable development, cleaner options such as rechargeable electric batteries are progressively becoming the norm.

There are many types of those: Nickel-Cadmium, Lead-acid, Silver-Zinc, Lithium-Ion, etc. The following graph produced by NASA shows that Lithium-Ion chemistry has the highest energy density and is consequently the best choice to store electrical energy in small volumes and low weights.

Electric bike Lithium-Ion battery energy density comparison

While still 60 times less energy-dense than gasoline, Lithium-ion cells are the best available alternative to store electric power safely and economically in personal vehicles.

The following diagram simplifies the discharge mechanism in a Lithium-ion battery, which is tantamount to the motor pulling power from it. Positive Lithium-ions travel across an electrolyte and a separator from an anode towards a cathode, which is two dissimilar conducting materials. The cathode then becomes more positively electrically charged than the anode. This creates a voltage between the anode and the cathode, which is essentially a driving force that pushes electrons between two points. The higher the voltage, the higher the force. This can be visualised as a waterfall. The taller the waterfall, the greater the force driving the water from its top to its bottom.

Electric bicycle Lithium-ion battery discharge mechanism

This voltage drives electrons across the electromechanical systems of your ebike. They leave the anode to go through the controller, followed by the motor and back to the cathode. As electrons move across the system, the voltage of the battery goes down. The charging process is the exact opposite. A voltage is applied across the cathode and the anode which forces electrons to move in the opposite direction and the Lithium-ions to go back towards the anode. This restores the driving voltage between the anode and the cathode for later discharge.

Electric bicycle Lithium-ion battery charge mechanism 2

These chemical processes are contained within cells. Today most cells, whether in laptops, cars or ebikes, are cylindrical pieces of metal. This allows to contain pressure better and increase batteries’ safety and resilience to their environment. These cells usually provide a nominal voltage of 3.6V. This means that they reach 4.2V when fully charged and progressively go down to a safe minimum of 2.5V during discharge after which a battery management system shuts your battery down to preserve its capacity and health.

Lithium-ion cells have to be connected and assembled to build a battery with a total voltage that is enough to drive its target electro-mechanical systems; the controller, motor and screen in our case. Individual cells are packed and connected in Series to increase the total battery voltage to the required value (for example, 36V). Once this value is reached, these series of cells are packed in parallel to reach the total battery capacity, the value usually quoted in Ah. An average cell packs 3.6V and 2.5Ah, hence a battery producing 10Ah at 36V most likely consists of 4 groups of ten cells connected in series, which are then connected in parallel. I know that this is tough to get your head around but the following diagrams, courtesy of Cadex, should help you understand:

Electric bicycle battery series assembly

Group of cells assembled in Series to increase total voltage.
Electric bicycle battery parallel assembly

Group of cells assembled in Parallel to increase total capacity once the desired voltage is reached.
Hopefully, you now have a better idea of the internal workings of your ebike or more generally your laptop, phone or car.

If you have any questions, do not hesitate to ask in the comments!

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