Slim 48V 13S 100A Active Balance BMS JNFN ANT 13EBB E Bike Downtube Pack

Frame-integrated e-bike batteries are the tightest packaging problem in light electric vehicles. A downtube holds a ten to twenty amp-hour pack, a controller, a harness and a management board inside roughly sixty-five millimetres of internal height, and the board has to do that without pushing the cell stack out of position. The JNFN ANT 13EBB is a 22 mm profile, thirteen series board for 48 V packs, with a 1 A active balancing stage that fits inside the tube rather than on top of the frame.

Thin does not have to mean passive. A 1 A transformer balancing stage is unusual at this thickness, and it matters because a downtube pack is charged to full every single day and left there. That routine pushes the strongest cell into the over-voltage cutoff first, and over a few hundred cycles the pack loses usable capacity that the owner notices as range loss. Moving energy between cells instead of bleeding it keeps the group together and keeps the range figure honest.

• 22 mm Board Profile: Component placement, terminal height and potting depth are all constrained so the assembly clears a standard downtube and in-frame cavity without modifying the cell holder.
• 1 A Active Balancing for Daily Full Charges: A pack that is topped up every night lives at high state of charge, which is exactly when cell spread forms; the active stage corrects it during the absorption window instead of leaving it to accumulate.
• UART plus Bluetooth in One Board: The UART link talks to the controller or display on the handlebar, while Bluetooth serves the phone application used for range estimation and cell inspection, so no separate module is needed.
• Sealed and Potted for Tube Mounting: The board is encapsulated against the condensation that forms inside a metal tube on a cold morning, a failure mode that quietly kills unprotected electronics in the first winter.
• Low Standby Draw: Standby current is kept under 1 mA so a bike stored for a month does not return with a flat pack and an unbalanced group.
• Charge and Discharge Paths Rated Separately: Charge current is limited to a value that suits a small pack, while the discharge path carries the controller's peak demand, so the board does not force a compromise on either side.
• Compact Harness Interface: A single locking connector handles cell sense, temperature and communication, which removes the bundle of separate plugs that usually occupies the last twenty millimetres of tube space.

Frame-integrated commuter and trekking e-bikes are the intended fit, including builds where the pack occupies a downtube or a seat-tube cavity and the controller sits in the motor housing. The board also suits compact cargo bikes with a 48 V pack and folding models where every millimetre of internal space is already allocated.

Battery builders who assemble packs in-house value the single locking connector, because it shortens final assembly and removes a common source of warranty returns caused by a partially seated sense plug.

Delivery includes the potted board, a colour-coded sense harness with the locking connector, two NTC probes and a wiring card. Each board is tested against a 13 series simulator with a full-charge soak, and the test record follows the serial number.

Ordering: samples from one piece, production quantities from one hundred. Harness length, connector type and UART protocol can be aligned with the drive system before shipment. A 24-month limited warranty covers the management board.