36V Seatpost Batteries for City and Folding E-bikes

The 36V platform is the optimal choice for city, commuter, and folding ebikes where weight, cost, and portability matter most. At 2.0–3.2 kg finished weight (36V 10Ah), these packs are engineered for riders who prioritize daily usability and low cost of ownership over maximum power output.

Our 36V BMS lineup is specifically calibrated for 10S cell configurations with active cell balancing, ultra-low self-discharge mode for seasonal storage (under 3% per month), and a configurable deep-sleep mode compatible with most display systems. The standard charge profile accepts 42V input, we supply matching 2A and 4A wall chargers with EU/UK/US/AU plug options and custom branding available.

For OEM buyers entering the European city-bike segment, this product ships with CE marking (EMC + RoHS), UN38.3 transport certification, and RoHS compliance, all backed by our documented quality control process. All documentation is in English with German translations available for distributors selling through German-language markets.

The two seatpost platforms

Model	Post lengths	36V capacity	Cell format
KT-S01	410 / 610 mm	5–7.5Ah	18650 only, Ø53mm tube
KT-S02	350 / 480 / 610 mm	5–15Ah	18650 or 21700

The KT-S01 is the simpler platform and the right one when 7.5Ah covers the ride. The KT-S02 adds a 21700 holder and a third post length, which is what takes the format to 15Ah — double the ceiling, and the reason most new concealed-battery programmes start there.

Choosing a capacity and length

Capacity and seatpost length move together on this platform. The 5Ah, 7.5Ah, 10Ah, and 15Ah options span 180Wh to 540Wh nominal, and the three tube lengths — 410mm, 480mm, and 610mm — set the ceiling on how many cells fit. A 15Ah pack needs the longest tube; specifying 15Ah against a 410mm seatpost is the most common mismatch we correct at the quotation stage.

Treat the published Wh figures as the comparison basis rather than converting them to a range claim. Real-world consumption on a city ebike varies widely with rider weight, terrain, assist level, and tyre pressure, so the same 540Wh pack behaves very differently across two markets. If you need a range figure for your own marketing, send us your motor and controller spec and we will state the Wh/km assumption behind any number we give you, so your claim is defensible.

Matching the pack to your drive system

The 15A continuous discharge rating is the constraint that decides compatibility, not the voltage. At 36V nominal, 15A continuous corresponds to roughly 540W of sustained draw, with 30A peak available for starts and hills. Drive systems that sit near or above that continuous figure — high-torque cargo or off-road controllers — belong on the 48V platform instead, where the 13S configuration and higher-current BMS options have the headroom.

To move from enquiry to a firm quote, send the usable internal tube length and clearance of your frame, the controller’s continuous and peak current draw, the display or communication protocol you need supported (the in-house 10S BMS supports a configurable deep-sleep mode compatible with most display systems), and the charger plug standards for your target markets. With those four items we can confirm a catalog configuration — KT-S01 or KT-S02, the latter also accepting 21700 cells — or tell you it needs custom work.