Choosing the Right Bike Battery
A battery is a vital component of an electric bike. Choosing the right one for your needs requires understanding a few basic concepts.
Amps, or Watt Hours (Wh), refer to a battery’s energy rating. A higher Ah rating means a longer range.
Batteries should be fully charged before riding. It is also recommended to leave the battery bike battery unplugged for a few minutes before each ride. This is to reset the battery and allow the power to transfer efficiently.
Size
If you want to ride further and faster on a single charge, you need more battery power. That’s why ebike batteries are typically available in 36V, 48V and 52V options, to best balance efficiency and performance for most riders.
Batteries are made up of individual cells, which come in different form-factors (think AA’s and AAA’s). A pack’s potential energy is measured in Watt Hours (Wh), which tells you how many continuous watts it can deliver for one hour.
Because these packs contain significant amounts of energy, they must be packaged and shipped safely. Reputable ebike vendors are likely to have their batteries UN Certified, which ensures safe and legal shipping and handling.
Voltage
Voltage is the amount of electrical pressure, or potential, a battery can generate. This pressure is translated into current, the flow of electrons through a circuit. Battery capacity is measured in amp-hours (Ah) or watt-hours, which are a direct result of volts and represent how much power a battery can deliver over time.
It is possible to measure the voltage of a battery using a multimeter, but be careful as it may not always give an accurate reading. First, set the multimeter to volts DC, a straight line and dots, as opposed to AC, which is indicated by a wavy line. Connect the red lead of the multimeter to the positive terminal of a fully charged battery and the black lead to the negative terminal. The reading should be somewhere around 12.6 volts for a 6 cell (12v) sealed lead-acid battery such as the gel or AGM types commonly found in classic motorcycles.
Typically, if a battery is below this level it has either been left on the charger for too long or there is an issue with the charging system itself, which needs to be investigated further. This is why intelligent battery chargers constantly check the state of charge of batteries to avoid overcharging them. This is also why a battery should never be allowed to fully discharge, as it will cause irreversible damage and potentially explode.
Weight
The battery pack in an electric bike typically contains one or more types of rechargeable cells. The most popular battery type is lithium polymer, which is similar to the batteries used in portable electronic devices like smartphones or cordless power tools. Compared to nickel-cadmium or lead-acid batteries, lithium-ion packs have a higher energy density, which means they can store more power in a smaller package.
Lithium-ion batteries are also more resistant to heat than other types of batteries. However, they require careful charging procedures and regular balancing to ensure optimal performance and longevity. If cared for properly, lithium-ion batteries can last for thousands of cycles.
Battery technology is advancing rapidly, and solid-state packs may eventually offer more range and less weight than traditional lithium-ion packs. However, these packs are still in the early stages of development and commercialization.
The shape and weight of the battery pack can influence how much pedal assistance the bike offers, as well as its handling and maneuverability. Some battery packs are fully integrated into the frame, while others can be mounted on a rear rack or saddle bags. Regardless of how a pack is mounted, it should be a safe distance from the wheels to avoid impact damage or overheating.
Life
The battery is an integral part of your electric bike and can have a major impact on its performance. Getting the most out of your lithium ion battery pack battery requires proper care and maintenance. The best e-bike batteries will last three to five years or more when correctly used and stored.
The most common type of battery used in e-bikes today is lithium-ion. This consists of a series of cells that contain lithium ions in an anode and cathode configuration. These cells can be charged and discharged thousands of times, which makes them ideal for powering the electric motor on an e-bike.
Lithium ion batteries are generally considered to be very safe. However, it’s important to note that these packs can be dangerous if they are improperly handled or stored. To prevent this, it’s essential to only purchase your battery from a reputable seller who ships their packs legally (aka: UN certified). Never open a lithium battery pack yourself, as the combustible lithium powder inside could explode. Avoid storing your e-bike battery in extreme hot or cold temperatures as these will hurt its lifespan.
Other factors that can affect a battery’s life include how hard the motor is working; riding uphill or over rough terrain will require more energy from the battery than flat, smooth riding. Rider weight and cargo load will also play a role as these extra forces on the motor will drain the battery faster.