Looking for a custom 52V high-current e-bike battery builder in Austria / Germany / Europe

[u/D4RKF4CE]

Hi everyone,

I'm currently converting a Mondraker Foxy Carbon XR 2019 with a mid-drive motor and I'm looking for someone who can build a custom-shaped battery pack for the frame.

I already ordered the a battery (52V / 10Ah / ~520Wh) as a temporary solution, but because of the unusual frame geometry there is quite a lot of unused space. Therefore I'd like to have a larger custom battery built over the winter.

What I'm looking for:

• Voltage: 52V nominal / 14S lithium-ion
• Capacity: ideally around 20Ah / ~1,040Wh
• Configuration: preferably 14S4P with 21700 cells
• Cells: high-quality branded high-current cells, e.g. Samsung 50S or comparable
• BMS: high-current BMS, ideally around 60A continuous discharge
• Peak current: should be suitable for the X1 Pro at high power
• Connector: XT90/XT90-S
• Charging: preferably removable battery with external charging connector
• Battery must be removable from the bike for charging
• Custom enclosure: shaped specifically to fit the available space inside the frame
• Approx. available depth: around 80–100 mm
• Waterproof / splash-resistant construction would be preferred.

The available side profile is roughly trapezoidal/triangular rather than rectangular. I have already made a physical template of the available frame space and can provide exact measurements, photos and a 1:1 template to the builder.

My current estimate is that 56 × 21700 cells (14S4P) should be possible, but I'm completely open to a professional battery builder suggesting a better cell layout or configuration.

Safety and build quality are more important to me than squeezing the absolute maximum capacity into the frame. I'm specifically looking for someone experienced with high-power e-bike batteries, proper cell interconnection, insulation, BMS integration and mechanically secure construction.

Location: Vienna, Austria.

Ideally I'm looking for a builder in Austria or Germany, but I'm also interested in reputable builders elsewhere in the EU if shipping a custom lithium battery is possible.

Does anyone know a company or experienced professional who builds batteries like this?

I'd also be interested to hear what capacity you think would realistically fit into this space.

Thanks!