How to choose the type of battery for an electric bicycle?
The battery (or accumulator) is one of the main elements of an electrically assisted bicycle (EAB ) since it powers the motor and the pedaling assistance system.
The autonomy and longevity of the electric assistance system depend on the battery, hence the importance of choosing the right battery for an EAB. Different criteria must be taken into account to make the right choice among the different types of batteries offered by manufacturers.
Let's take a look at all the information you need to know in order to choose the right type of battery for an electric bike.
The different types of batteries for an electric bike
Electric bicycle batteries can be made of different materials such as lead, nickel or lithium. However, lithium is the most common material used in EAB batteries today.
Lead and nickel batteries
The first batteries for electric bicycles on the market were lead-acid batteries, then nickel-acid batteries.
However, this type of battery has a major disadvantage: their weight. They increase the total charge of the bike, making pedaling more difficult without electric assistance (especially when the battery is flat).
Today, most batteries for electric bikes are lithium batteries. The batteries for electric bikes are thus much lighter. The lithium battery offers many advantages such as a low self-discharge rate, a lifespan of up to 1500 cycles, a high energy density and a low internal resistance.
Nevertheless, it is important to distinguish several types of lithium batteries:
- Lithium ion batteries (Li-ion) ;
- Lithium ion polymer batteries (Lipo);
- Lithium iron phosphate batteries (LiFePo4);
- Lithium prismatic batteries;
- Lithium-ion Nickel-Cobalt-Manganese (Li-ion NCM) batteries.
Lipo batteries are slightly more efficient than Li-ion batteries with a voltage of 3.6 V for Li-ion and a voltage of 3.7 for Lipo. The Lipo battery is also more resistant to overcharging and electrolyte leakage. However, it is more expensive.
LiFePO4 batteries have the advantage of offering a longer lifespan even if the performance is limited. Prismatic lithium batteries owe their name to their square or rectangular shape and are quite similar to Lipo batteries. Present on electric scooters, prismatic lithium batteries are rarely used on electric bikes.
Finally, Li-ion NCM batteries are the most efficient and are part of the recent technologies that improve the performance of EABs. These performances are due to the presence of Cobalt in the composition of this type of battery. Indeed, the higher the cobalt content in a battery, the better its performance and durability.
Criteria for choosing a battery for electric bikes
Choosing an e-bike battery based on its model is not enough. It is also important to consider other criteria such as autonomy, durability and location.
Choose the battery of your EAB according to the autonomy
The autonomy of a battery determines the number of kilometers that it will be possible to make with a battery charged to 100 %. The autonomy is indicated at the time of purchase, but remains theoretical since it depends on many factors such as the driving conditions or the weight of the cyclist. The best batteries on the market offer an autonomy that can exceed 200 km.
In order to choose the right battery, it is important to determine your needs. It is useless to opt for the maximum autonomy if it is not essential. On the other hand, it is important not to underestimate the mileage required to make daily trips or occasional rides.
In addition to the autonomy, the recharging time of the battery can also be a criterion of choice.
Choosing an electric bike battery based on durability
The lifespan of a battery is also an important element to take into account. The durability of a battery is expressed in charge cycles and can vary from one model to another. The life span can also be more or less important depending on the good or bad use of the electric bike and its assistance.
If some batteries of VAE announce a lifespan of 1500 cycles, the average electric bicycle has a battery offering an average durability of 600 cycles. This means that the battery will work for 5 to 6 years with daily use.
Some tips on how to use your electric bike will also help preserve its battery life:
- recharge the battery at least once a month, even if it is not used;
- Avoid using the assistance system if the battery level is below 30%;
- Avoid using the assistance system if the battery level is below 30%; - Prefer a battery charge level between 30 and 60% as much as possible;
- Keep the battery away from humidity and cold;
- Use an original charger or a compatible charger.
Of course, the more the cyclist uses electric assistance, the faster the battery will wear out. Adapting your riding to the situation (braking, climbing, descending) is a good way to use the assistance of your electric bike correctly and thus preserve the life of the battery.
Choosing the battery for your electric bike according to its location
Finally, it may be wise to choose the battery of your electric bike according to its location. The battery of an EAB can indeed be located :
- on the sloping tube of the frame ;
- directly integrated in the frame;
- on the rear rack.
A battery placed on the slanting tube of the frame has the advantage of being located right at the center of gravity of the bike. Thus, it is possible to keep a good stability and a better handling of the EAB. The most recent models of electric bikes integrate the battery directly into the frame (integrated batteries).
However, if the frame is low, it is better to opt for a place on the rear rack.
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