How does an e-bike battery work?
An e-bike battery essentially consists of many individual lithium-ion cells connected in series and parallel to achieve the desired voltage and capacity. The most common cells are 18650 or 21700 types—similar to those found in modern cordless drills or power banks. A cell module typically consists of 10 to 13 cells connected in series (for a voltage of approximately 36V to 48V), multiplied by several blocks connected in parallel—depending on the desired capacity.
The capacity of a battery is measured in watt-hours (Wh) and is calculated by dividing the voltage (V) by the capacity in ampere-hours (Ah). For example, a 48V, 17Ah battery delivers 816 Wh—that's quite a statement!
How many cells fit in the bicycle frame?
A modern e-bike with an integrated battery offers a surprising amount of space – but there's a limit somewhere. A classic in-tube frame (i.e., with an integrated down tube battery) typically accommodates between 40 and 60 cells. With efficient arrangement and the use of high-quality cells (e.g., with 3.5 Ah per cell), this is enough for capacities of up to 800–900 Wh.
Theoretically, more is always possible, battery stinginess and range anxiety will then be a thing of the past – but then you quickly reach physical and technical limits:
More power = more weight?
Clearly, the more watt-hours, the heavier the battery. A typical 500 Wh battery weighs around 2.5–3 kg. At 800 Wh, you quickly approach the 4 kg mark. Anyone who wants even more—for example, with an additional battery (range extender) or a dual-battery system—must also expect a change in handling. Especially off-road, the weight in the frame or on the luggage rack can negatively impact handling.
It is also important to note that more cells require a longer time to charge.
DIY: Build your own e-bike battery?
For tinkerers with technical know-how, the topic of DIY batteries is an exciting field. Various forums and YouTube channels offer instructions for building your own battery packs – including cell configuration, BMS (Battery Management System), and charging electronics. Popular examples include self-builds using Tesla cells or upgrading old batteries.
But beware: DIY projects are not entirely without risk . Improper handling of lithium cells can lead to short circuits, overheating, or even fires. Furthermore, the legal situation regarding homemade batteries in road traffic (StVZO) is unclear.
What is currently the most powerful battery?
In the premium segment, batteries with up to 1,000 Wh are now available, usually as a combination of two batteries. In compact, fully integrated frame solutions, the 800 Wh limit is currently a milestone.
👉 One example of this is the new MYVELO Himalaya e-bike with the Bosch Powertube 800 Wh – a true powerhouse for long tours and challenging routes. Despite the powerful battery, the bike remains surprisingly balanced and capable of off-road riding – a testament to how advanced technology has become.
Conclusion: Choose battery capacity cleverly
A "powerful battery" means more range – but also more weight. Those who frequently travel in mountainous terrain or carry heavy loads benefit from larger batteries. For commuters or recreational riders on flat terrain, however, a 500–625 Wh version is often sufficient. The most important thing is that the battery, motor, and intended use are well matched. Riding style is also a factor, for example, how often Eco mode is used.
Tip : If you're considering a modern battery system when purchasing an e-bike, consider not only capacity but also charging time, weight, and compatibility. A battery like the one in the MYVELO e-bikes not only delivers plenty of power, but also a clean design and optimal off-road protection.
