We want to share some of the knowledge we have learned from our experience over the years. We hope you find it useful and I know they can always email us with your questions to us.
It is relatively easy to compare traditional bikes together, for reading the specifications or just looking bikes you can see what the differences are and where the money goes. With electric bikes or xe đạp điện in Vietnamese , the differences are not so obvious because it has electronic parts. Is something like buying a car or a motorcycle.
It takes years to truly understand all the technologies used in e-bikes and the interaction between them, and how they affect the experience of riding an electric bicycle.
The performance of an electric bike is not only down to whether or not employ the latest technology in batteries. It is a combination of battery chemistry, electronic controller, the core composition engine, wiring and connectors used, the degree of quality of all materials, system efficiency and attention to detail factory.
One may be surprised by how power is integrated with your driving style when energy enters the engine, when cut, or soft or aggressively happens in both cases. Are the gears properly adapted to the power and to its intended use?
For example, if you have knee problems and ride an electric bike with cadence sensor and a high development (chain on the smallest sprocket) it can be very hard since the started pedaling with no fluid enough for the sensor pedaling send the signal to the controller to boot attendance.
In addition, changing gears, need to be already in motion … This does not necessarily mean that people with knee problems can not use an electric bike speed sensor , moreover, can be advantageous when lower gears are used as the engine will deliver its full power pedaling applying minimal pressure and, hence freeing the knee voltage. It is very important that the manufacturer has thought about the practical aspects of its design and programmed control unit accordingly.
There are so many electric bikes on the market that can be difficult to choose between different makes and models. Adding to the confusion many brands of electric bikes have models that look identical and very similar specifications, but very different in price and performance. As if that were not enough, we often encounter with features that, on paper, are not very realistic.
Another difficulty is that the electrical components for bicycles are not standardized, as components for traditional bicycles. This means that if you can not buy a piece through your dealer , probably can not easily get anywhere else.
Europe is home to some of the largest companies in the world and more powerful bikes. Very few, like Sparta, were pioneers of electric bikes, most are just entering the market power and in our tests, some known bicycle brands have not gone very benefit.
It can be said that without understanding very well electric bikes, managers of big brands have managed to play a clever hand. They have chosen to say electrical systems, standard, leaving the main argument decision to buy a bike, bicycle components, some what better understood.
This is convenient for businessmen, but restricts consumer choice. At fairs Bicycle 2011/2012 we have seen almost all brands of traditional bicycles, either with a Panasonic , Bosch or systems BionX. So the only thing left to select a new ebike is the style and components bicycle.
Can three drive systems meet the needs of all consumers? From our experience and our customers know we do not.
Most publications are influenced by advertisers and authors of many of them have never seen the bike on which to write. Feel safe defending big brands. This often leads to a lackluster ebike is announced as the best. There really is no “best e-bike “because driving styles and performance vary so dramatically that each client needs to try several products to find what best fits your needs.
We hope this guide will serve them for this purpose.
Legal : First, we must be clear what an electric bicycle pedaling asistitido for legal purposes and distinguish electric mopeds. The former do not need insurance or driving license and are, for legal purposes, exactly like a traditional bike. To be considered as such a pedal assist electric bike must meet certain characteristics.
- The engine must not exceed 250W rated power.
- The maximum speed that can reach should not exceed 25 km / h .
- The engine can only be activated while pedaling and must stop automatically when the cyclist stops pedaling or engage the parking brake.
- The bicycle as a whole must not weigh more than 40 kg .
These are the main requirements for a pedal assist electric bike complies with Directive 2002/24 / EC .
Comfort : It’s very important when making such a large investment. If you are not comfortable on a bike, it will not use or at least not leverage its full potential. When a person feels comfortable in yourebike and therefore safe, these products can totally change your mindset about local transportation.
Security : Closely related to the feeling when riding and how power is integrated with the driving style and terrain. Some bicycles pedelec need one or two turns of pedals before the pedaling assisting the engine, and therefore may be harder starting.
On the other hand, some electric bikes are very aggressive from the start and can be difficult to control in tight spaces.
Maintenance : The ability to properly maintain the product is paramount. Too many e-bikes that are designed to offer an attractive image and not to provide a long service life at low cost.
Most systems acclaimed ” crank drive “with the engine shaft bottom bracket work with all components in a single sealed unit. Such systems are quite nice and tidy, but …. if one component fails, we must replace the entire unit with a great cost. We must emphasize all aspects of a product to ensure that each customer makes the best purchasing decision for yourself, analyzing the advantages and potential disadvantages.
Another critical point for electric bikes are the brake levers. In traditional bicycle brake lever always spoil. They are the first thing that touches the ground when the bike, or wall or other bikes to park them fall. The same applies to electric bicycles, except that this often results in that the electronic switch is damaged brake lever and the consequent outage permanently. In most electric bikes we see these switches are not easy to replace, so it’s something worth considering when different bikes are compared.
Reliability : The reliability of an e-bike depends on the quality of each the components used in their manufacture. When purchasing a e-bike most of us have a budget in mind, and from there, our goal is to get as much inside. However, the old adage “you get what you pay for” is not always true here. We’ve seen a lot of very expensive electric bikes that have serious quality problems. In our experience, a less expensive electric bike can be very reliable if not regularly expose extreme situations (electrical and mechanical). For example, if you live in a mountainous place, you may have to spend a little more to find a bike that will pave the outstanding reliably for many years.
So how do you choose where to spend your money and make sure you get what you expected? In this regard, it is important to learn a little about the important features of an electric bike.
Weight: The weight of an electric bike is essential for its operation, plus there are legal limitations thereon (see Rules and Regulations ). The heaviest parts of an electric bike is the battery box and the motor.
Table : The lightweight frames are almost always good, unless you intend to make “trips off-road “or descent because, usually, a light box sometimes sacrifices flexibility and endurance.
– Aluminum alloy 6061: good for use ” off-road “moderate and city.
– Aluminum alloy 7005: good for road bikes and urban use.
– Steel: good for heavy use. Super resistant. Much heavier than aluminum.
Battery: Every time they are coming to market lighter batteries that offer the same autonomy that heavier. This topic will detail later.
Motor : It is the component that provides the turning force to assist the pedaling.
Thanks to constant improvements engines are getting smaller, but like any tech product, are more expensive. The engines have better materials, lighter weight and size and shrinking, while still providing the same power.
Delve into these last two aspects in the next issue.
There are mainly two types of motors used in electric bicycles . All have their pros and cons:
Brush motors : These motors have very good press. Are larger, heavier and noisier than their counterparts brushless addition, although quite economical, maintenance free. However, if one takes into account that the motor can run to 20,000 km maintenance and, after maintenance, the engine will continue running like new, your prospect can begin to change. Therefore, we can say that the brush motors have proven to be a solid choice at a lower price.
DC brushless motors or BLDC : also known as brushless . They are smaller, lighter and certainly quieter than brushed motors. The technical differences are not as important as the relative performance in different applications and truth are the best choice for e-bikes in recent years, although a good motor with brushes can be more robust in demanding circumstances and can be best climbers to the given power.
Since the introduction of the hub motors without sensors, there has been a significant improvement in the reliability of these motors. Effect sensors Hall are no longer necessary because the position of the armature can be detected by EMF or by detecting the magnetic field, and this reduces the necessary electronics on board motor, improving reliability.
Brushless motors have a linear power response speed, which means that the maximum torque is available from the start in stop and reduces smoothly through acceleration.
Something that is not often mentioned is the efficiency of a motor. What power we are talking about when we ask 200Watts or 250watts, is the power input or output?
When a current is applied to a motor, it rotates with a measurable force Nm. The more efficient an engine with more force (Nm) rotate to a given input power. Efficiency, therefore, is given by the difference between input power and output power.
In other words, the efficiency of an engine which indicates amount of energy received by the motor is converted into movement of our electric bike . Always be some power due to resistance in the copper coils, the resistance between the magnetic fields, and because the harmonics generated when the engine is running.
The efficiency is a factor that explains the differences in performance in some electric bikes with the same specifications.
Ideally engine medium-low power consumption (from 200 to 500Watts) is accompanied by a high peak power, for example 1.5Kw. Thus, they have the necessary power without creating high energy demands could damage the battery or wiring.
Peak power is the maximum power output of an engine can reach for a few seconds.
Position of engine
There are basically two engine positioning options
The HUB those engines are coupled to the wheel hub. The vast majority of electric bikes use these engines.
These are the main advantages of an engine of this type:
The center of gravity is relatively low, maintaining a good balance.
Easy access for repair or replacement, without any other component is affected.
However, we can also find some drawbacks:
Motors located on the axis BB
Panasonic and Yamaha are betting heavily on this type of system, whose sales have soared in Europe but not both USA.
We can identify the main advantages of this system:
- The motor may be smaller because the housing allows the heat is released more effectively.
- The engine is usually in the bottom of the shaft bottom bracket lowering the center of gravity of the bicycle.
- The engine can stay close to their optimum operating point using the gearshift of the bicycle.
- Using the shifting of the bicycle, these motors can provide more effective assistance pending the HUB engines, to equal power.
- By using low power, reliability is improved.
Also here we have disadvantages:
The output power and therefore, the performance is limited by the strength of the chain and sprocket. Standard pinions and chains were designed to human transmission through pedaling, which means that the amount of mechanical energy that can be added is relatively small.
Batteries are electrochemical components and have their own, say, “personality”. It is almost impossible to find two identical behavior batteries. Although two people the same model are purchasedelectric bike at the same time, they can have completely different experiences with their batteries.
We have studied the whole theory on batteries (that can keep one busy for a long, long time), but the most useful information has come from our customers. Often, the information provided by laboratory tests can not replace it emerges from the experience of end users with their batteries.
The industry of electric bicycle has been waiting to become an important enough to allow more efficient technologies batteries are offered at reasonable prices sector. This is already beginning to happen.
A battery is not only a solid piece, is a collection of “cells”. The cells are complete units electrolyte with an anode, a cathode and produce electricity from a chemical reaction.
Each type of cell has a nominal voltage. For example, NiMH (nickel metal hydride) is about 1.2 volts per cell, and thus need a lot of cells combined to obtain the voltage used in an electric motor. Thus, 30 cells would get approximately 36 volts, thus obtaining a useful voltage.
How the measured capacity of a battery?
Usually when someone asks about the capacity of a battery, is looking for basically two things: (1) the amount of energy stored in the battery cells (? How far I can go); and (2) what current cell rate (how much power and how fast?) are discharged
The amps are the most common to describe the amount of stored electricity in the cells form. The ability of a cell in ampere / hour (Ah) is also full battery capacity in Ah. A cell 7 Amp is 7 Ah to 1.2 volts. With the example above would need 30 of them to obtain the required voltage, but would still only 7 Ah useful energy to that voltage.
To put it another way, more Ah, we go further and faster. However, more Ah cost more money, and weigh more.
When we read Wh (watt / hour) on battery specifications, we are more or less to what we have been explaining about Ah, but in this case the voltage is also considered. For example, a battery of 360 Wh is only 10 Ah battery to 36 volts (36V 10Ah x = 360Wh).
Maximum current means essentially “what is the maximum download speed of a cell?”. Think of it as a bucket of water. The hub is the cell and water is electricity (the larger the cell, the greater the amount of water), where the water leaves through a hole in the hub. Thus, the larger the hole, the faster will the water.
In terms of battery, if the download (the hole) is not large enough, then the engine may not be able to get enough energy (water) to operate with maximum performance.
The measuring unit is described in terms of maximum amperage that can support cell per unit time. Another way to describe it in terms of “C” or what is the same, the rate at which the battery can be discharged for one hour = 1C. For example, if the battery discharge 10 amps for one hour means you will have a maximum current of 10Ah to 1C.
Problems in construction of batteries :
Most consumer batteries electronics utilize a handful of cells. For example, a battery of a mobile phone of 3.6 volts, may have three NiMH batteries at 1.2 V battery in a plastic box. The electric bikes , usually no more than 30 merged cells. Each cell is connected to another with a small metal connector. Each connector is a potential point of mechanical failure, and a small resistance.
Lead Acid (SLA)
Pros : average energy density, maintenance, proven in millions of electric, cheap bikes.
Cons : heavy batteries, very short life cycles, no fast load option and not easy storage.
Nickel (NiMH and NiCd)
Pros : average energy density, relatively fast loading, average weight.
Cons : suffer from memory, slashing performance at low temperatures, difficult storage effect.
Litio ion (Li-ion)
There are numerous types of Lithium. It is essential to know one needs to avoid mistakes when choosing a battery, otherwise you may not get the performance you expect. In addition, improper use of the battery may lead to a shorter life cycle, with the costs that entails.
Here’s where it gets really interesting theme, so you have some basic knowledge required to understand the role of chemistry in different Lithium:
Lithium batteries are formed by two parts: the anode and cathode. Energy is released when the ions (in this case, lithium ions, Li) move from the anode (positive) to the cathode (negative) through the electrolyte. Anode is usually graphite, the electrolyte is usually a lithium salt solution. Improvements in this field of chemistry occur primarily within the material it is made the cathode. Some of them are: Lithium Manganese LiMn2O4, Lithium Nickel Cobalt Manganese LiNiMnCoO2 (NCM) , Lithium Manganese Cobalt LiMnCo , ferrous or Lithium Iron Phosphate LiFePO4 .
Pros: light weight, high energy density, durable, maintenance free, fast charge and can be stored. Also have over 500 recharging cycles until 2000 in the case of LiFePO4 life.
Cons: expensive, may be unstable, the cells suffer shit and downloads at different rates may jeopardize the orderly functioning of the battery.
Lithium Polymer (Li-Po)
Pros: It is one of the available lighter batteries with a very high density of cargo, maintenance, fast loading, high stability demonstrated in tests extreme laboratory, speed low self-discharge, can be stored if precautions are taken, range operating temperature.
Cons: expensive, will suffer if stored incorrectly, you may suffer thermal runaway and represent a fire hazard if charged after a period of improper storage or if the BMS has failed catastrophically.
* For months, the emergence of Li-NCM developed by manufacturers like Samsung are pushing the market to other lithium chemistries for high charge density which reaches 200Wh / Kg, which means, comparing with LiFePO4, reduced to half the weight and volume of the battery to store the same load. Our electric bike or xe dap dien Bolt trekin is equipped with this type of battery.
Are the brain’s electric bike – xe đạp điện, determine how much electricity flows from the battery to the motor by regulating its proper functioning. Internally usually a chip of about 10cm x 6cm protected by an aluminum housing.
The brushless DC (BLDC) require a driver to turn the engine and not worth a simply switch.
The controller determines the following:
When entering the engine to attend
Much Aid provides engine
The outage undervoltage / voltage or high temperature in the engine or battery (advanced and sensor)
Energy recovery function during braking (reverse battery)
Help to start at 6 km / h (maximum allowed by law to use the throttle and no pedaling)
For an electric bicycle is considered as such in EU, the engine can only help while pedaling. To ensure this, there are several technical solutions:
The torque sensor / par : is a sensor that detects the force exerted by the driver on the chain through the pedal stroke. The stronger the greater pedaling support received from the motor.Disadvantage: tends to a cadence (pedaling speed) slow heavy, and therefore unhealthy.
Cadence : here the motion sensor detects the speed of rotation of the cranks. The faster spin, gives the engine more assistance. Disadvantage: The pedaling slowly have very little support and have to get used to go on a 80 RPM or increase the number of magnets available in the magnetic sensor disk to simulate increased rate.
Sound drivers simply have a rotating motion detection, ie, the motion sensor on the crank (bottom bracket to be exact) only detects rotating and then gives 100% attendance, or allows use d eun accelerator or a manual switch between manual 3-6 speeds, which is enabled only by pedaeleo him as saying.
Finally it is important to distinguish between motor controllers with and without Hall sensors: the first are gentler on departures from 0km / h especially when it comes 250W engines without gears; others in changes are more reliable and consume less power once launched.