About this replacement
Nintendo Switch Joy-Con — 3.7V Li-Polymer Replacement Battery (HAC-006 / HAC-BPJPA-C0)
This is a 3.7V, 450mAh Li-Polymer replacement battery for the Nintendo Switch Joy-Con controllers. It fits HAC-015, HAC-016, and HAC-A-JCR-C0 variants using OEM part numbers HAC-006 and HAC-BPJPA-C0. Swap this cell when your Joy-Con no longer holds a charge or stops powering on entirely.
- Joy-Con Left and Right compatibility: Both HAC-015 (Left) and HAC-016 (Right) controllers share the same battery footprint, connector pinout, and BMS handshake — one cell works across both units.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on HAC-016 hardware. The onboard BMS accepted the cell without fault flags, and the charge IC ramped to its standard 4.2V termination voltage without triggering any protection cutoff.
- Fuel gauge calibration after swap: After installing this cell, run one complete wireless play session until the Switch automatically parks the controller at cutoff — do not manually recharge before that point. The fuel gauge IC sets its empty reference on the first full discharge, so skipping this step causes the battery indicator to jump or report inaccurately for several sessions.
Joy-Con dropping wireless connection before the battery indicator hits empty
Joy-Con controllers combine Bluetooth radio transmissions with HD rumble activation simultaneously — this stacks two high-draw loads on a 450mAh cell at once. A degraded or partially discharged cell can sag below the BMS undervoltage threshold under that combined load even when the Switch still shows one or two bars. The BMS interprets that voltage dip as a protection event and cuts output, which the console reads as a dropped connection rather than a low-battery warning. Replacing the cell resolves the sag; after one conditioning cycle the voltage under combined wireless and rumble load stabilises above the 3.0V cutoff floor.
Battery percentage jumping or freezing after cell replacement
The Switch uses a fuel gauge IC that tracks battery state by learning the discharge curve of the installed cell. When you swap in a new cell, the IC still holds the learned curve of the old, degraded cell — so percentage readings jump, freeze, or drop sharply until it recalibrates. This is not a fault with the replacement cell. Run three to five complete discharge-to-cutoff and full-recharge cycles without interrupting them mid-way, and the gauge IC maps the new cell's actual curve. After that, percentage reporting tracks within a few points of real remaining capacity.