Connector Pinout
Which signal sits on which pin of a battery connector — the detail that decides whether a pack works or damages the bike it is plugged into.
Same connector, different wiring
Two packs can use physically identical connectors and be completely incompatible, because the pinout is a separate decision from the housing.
A typical e-bike connector carries more than power: positive, negative, and often an ignition or enable line, a data line for BMS communication, and sometimes a separate charge path. Which pin carries which is set by the bike manufacturer, and there is no industry standard.
Fitting a pack with a mismatched pinout ranges from nothing happens to a reversed polarity event that damages the controller. This is the single most consequential detail on a replacement battery project, and the one most often supplied as a photograph rather than a specification.
Common options
We build to XT60, Anderson, Higo Z910, Julet 3-pin, DC2.1, aviation connectors, or a custom OEM pinout. The housing choice usually follows the bike; the pinout must match it exactly.
Sequencing can also be designed in. A connector where a low-current pin mates before the power pins can provide the enable signal or serve a precharge function mechanically, avoiding an inrush arc on connection.
Sealing and current rating
Two properties beyond the pinout deserve checking.
Current rating. The connector must carry the pack’s peak, not its average. An undersized connector is a resistance and heat source at exactly the point where it is hardest to inspect.
Sealing. A pack rated IP65 with an unsealed connector is not IP65 in service. Mated and unmated ratings are different, and packs that are frequently disconnected need the unmated figure to matter too.
Photographs are not a specification
For an OEM build, send the connector part number and the pinout diagram. For a replacement build, send clear photographs of the connector and, where possible, a sample unit — measuring a real connector removes the guesswork that photographs leave.
A pinout inferred from images is a risk we would rather not take with your customers’ controllers.
Working on a pack specification?
Send us the voltage, capacity, current draw, and target markets. We reply with a specification you can review rather than a price with no working shown.