Custom Battery Packs 1ICP/18/650 Replacement Battery 3.6V 2250mAh

Custom Battery Packs 1ICP/18/650 1S1P — 3.6V Li-ion Replacement Battery

This is a 3.6V 2250mAh (8.1Wh) lithium-ion single-cell replacement pack for the Custom Battery Packs 1ICP/18/650 1S1P configuration. It measures 66.00 × 21.80 × 18.50mm, matching the original cell footprint. Use it when the original pack has degraded capacity or fails to hold a charge.

• Single-cell 1S1P configuration: One cell, no series or parallel wiring — voltage stays at the nominal 3.6V rail the host device expects. There is no mid-pack balancing circuit to negotiate, so the BMS handshake depends entirely on cell voltage being within the device's acceptance window at installation time.
• Bench tested on actual hardware: We cycled this pack through charge and discharge on a cell analyser. The BMS cutoff triggered correctly at the low-voltage threshold, and the charge termination stepped down cleanly from bulk to taper current without anomaly.
• Fuel gauge calibration after swap: After installing, run one full charge-discharge cycle before trusting the capacity indicator. Integrated fuel gauges track coulombs against the old cell's profile — they need one full cycle against the new cell to recalibrate the state-of-charge reading accurately.

Pack not accepted by device after swap

Some host devices run a voltage-range check at power-on before allowing the pack to discharge. A new cell ships at storage voltage — typically 3.6V to 3.7V — which can sit just outside the acceptance window on certain charge ICs. If the device rejects the pack immediately after installation, place it on charge for a full cycle first. Once the cell reaches 4.1V–4.2V, the host's voltage check will clear and normal operation resumes.

Pack not reaching full charge on the first cycle

On the first charge cycle, the charge IC may limit current more aggressively than it will on subsequent cycles. This is normal — the controller is characterising the new cell's internal resistance before allowing full current. The result is a longer first charge and a capacity reading that appears low. Run a second full charge-discharge cycle and verify the pack reaches 4.20V at termination.