The WATT Bikes are designed so that no visible battery is needed. The battery is fully integrated in the down tube of the frame. Charging is done via a connection on the side, where you can also have a USB connection.
How far you can cycle with a full battery (the range) depends on a number of factors. It depends on your own weight, the support position you choose and the circumstances in which you cycle. In case of a strong headwind, for example, and support position 5, the range is smaller than on a flat road with wind and support position 1. In general you can assume that you can cover a distance of between 30 and 60 kilometers. More than enough for daily trips in the city.
You charge a fully discharged battery in 3 hours. In practice, you almost never empty the battery. On average, the Dutch cycle about 2.8 kilometers per day. But even if you cycle a multitude of bicycles, you do not get 40 to 70 kilometers every day. So you can go a few days ahead with a full battery.
To get the highest possible return from your battery, here are some tips.
The average lifetime of a battery is three years. Keep in mind that the range of a battery can then decrease. However, replacing the battery is done easily. You can do this yourself or have it done by a bicycle repairer. You can order a new battery here online.