1. What is Voltage Variety
- Diverse voltages, such as the common 36V, 48V, 52V, 60V, and 72V, define the power dynamics of ebike batteries. A higher voltage often translates to increased motor output, enhancing the overall performance of the electric bike.
- Most commercially sold ebikes use 36V or 48V batteries. Some use 52V systems.
- 60V or 72V batteries can commonly be found on electric scooters, DIY ebikes or high-performance electric bikes.
2. What is Watt-Hour (Wh)
- The watt-hour (Wh) rating of an ebike battery, derived from the multiplication of voltage (V) and amp hours (Ah), directly correlates with its energy storage capacity.
- For example, a 48V and 10Ah battery results in a 48x10 = 480 Wh capacity, influencing the potential range of the ebike.
3. Is a Higher Voltage Better?
- Yes, we believe so.
- Power (Watts) = Voltage (V) x Amperage (A): a higher voltage x lower amperage is typically more efficient compared to a higher amperage x lower voltage.
- Transferring power using higher voltages means more efficiencies such as smaller electrical cables and components.
- High voltage itself doesn't lead to increased heat or danger. High amperage or resistance poses such risks, resulting in heat, melted wires, or failures.
- For example, modifying an ebike motor's voltage from 48V to 60V usually doesn't cause failure. However, increasing amperage from 12A to 45A often leads to motor burnout under loads.
4. Efficiency Equation - How Far Can I Ride?
- Efficiency emerges as a critical factor in determining an ebike's range. Beyond the battery's intrinsic capabilities, external elements like tyre tread, headwinds, uphill terrain, and the combined mass of the rider and bike play pivotal roles in influencing the Wh per kilometre (Wh/km) efficiency. Recognising and optimising these variables are key to unlocking the full potential of an ebike's range.
- For an ebike with a 250W motor, the estimated riding distance is calculated by dividing the battery's capacity (e.g., 500Wh) by the average power usage (250W), giving the non-stop riding time. For instance, a 500Wh battery provides approximately 500/250 = 2 hours of continuous riding. The actual range varies based on power usage – more power reduces time, while less power increases it;
- Assuming an average speed of 25km/hr (continuing with the example above), the total distance is obtained by multiplying the riding time (2 hours) by the speed (25km/hr), resulting in around 2x25 = 50km for a 500Wh battery. However, these calculations are idealistic, and real-world conditions can alter the range by up to ±40%, influenced by motor power fluctuations. However, if you are consistently riding the same route, similar weather conditions and same weight then this can be an extremely accurate estimate.
5. Is Less More?
- When considering an ebike purchase, the battery capacity becomes a decisive factor. Opting for a battery below 400Wh may compromise the overall experience. Smaller batteries not only limit the range but also contribute to additional weight and heightened drag resistance of a bicycle, potentially outweighing the benefits of an electric bike for many users