E-MTB batteries

How to choose an electric mountain bike battery

You do not really choose a battery: you replace it with the same model or add a range extender. The motor system and the frame's battery compartment determine what fits, not the capacity you would like to have.

Compatibility is essential

• The battery must match the motor system : Bosch (Performance, CX, Smart System), Shimano STEPS (E6000, E7000, E8000), Yamaha or Brose.
• Different generations from the same manufacturer are not compatible with each other. A Smart System-generation PowerTube will not work on a bike from the previous generation, even if it fits in the compartment.
• As for the frame: integrated in the down tube — mounted horizontally or vertically depending on the compartment — or external magnet, attached to the tube with its mount.
• Note the exact model number printed on the original battery. It is the only reliable guide.

Capacity

• It is measured in watt-hours (Wh) : 400, 500, 625, 750 or 800 Wh depending on the model.
• Fitting a higher-capacity battery is only possible if the frame's battery compartment can accommodate it: a frame designed for 625 Wh will not always take an 800 Wh battery.
• Actual range depends far more on the assistance mode, elevation gain, total weight and temperature than on watt-hours alone. The same bike's range can vary threefold depending on the ride.

Range extenders

Some systems accept an additional battery mounted on the bottle cage bosses, such as the Bosch PowerMore. It connects to the main battery and extends your range without replacing anything. Check two things: that the frame has the mounting bosses and that your system generation recognises the battery.

Mounts, cables and connectors

This page also brings together battery mounts, connecting cables, cable grommets and upgrade modules. These parts can get damaged, be lost during disassembly or change with system updates; they can be ordered separately.

Maintenance and lifespan

• A lithium battery ages even when you are not riding. For winter storage, keep it at 30 to 60% charge, protected from frost and at room temperature.
• Avoid repeatedly draining it completely: this causes the most wear to the cells.
• Never spray the contacts with water, and dry them after a muddy ride.
• Expect 500 to 1,000 cycles before a really noticeable loss of capacity, equivalent to several seasons of regular use.

To find out more: Understanding electric bike battery range

See also: Electric mountain bike drivetrain parts · 29-inch MTB Wheels · MTB rear shocks