About this replacement
Nolan N-COM B902 L / B902 R — 3.7V Li-Polymer Replacement Battery (BATTERIA 07)
This is a 3.7V 900mAh Li-Polymer battery for the Nolan N-COM B902 L and B902 R motorcycle helmet communication systems. It replaces OEM part BATTERIA 07 (also listed as SPCOM00000109). When the original cell loses capacity after extended use, the helmet intercom cuts out faster or stops holding charge altogether — this pack restores full operation.
- B902 L and B902 R compatibility: Both units run the same 3.7V cell with identical connector pinout and BMS handshake protocol. The L and R designations refer to left- and right-side helmet mounting — the battery itself is shared across both variants.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the B902 platform. The BMS accepted the pack without error flags, and the protection circuit tripped correctly at the low-voltage cutoff threshold under simulated audio and radio draw.
- First charge in the helmet before riding: Seat the pack and place the helmet unit on charge for a full cycle before your first call. The N-COM firmware logs the new cell during this cycle — skipping it can cause the talk-time indicator to read incorrectly for the first several uses.
Why the B902 cuts out mid-call even with a new battery
The B902 draws current simultaneously from the audio amplifier and the Bluetooth radio. On a fresh or recently replaced cell, this combined load can briefly pull the terminal voltage below the BMS cutoff threshold — particularly at high volume or in cold ambient temperatures. The protection circuit reads this as an unsafe low-voltage event and disconnects the pack. The fix is to allow 3–5 full charge and discharge cycles so the cell's internal resistance stabilises, which keeps voltage sag within the BMS tolerance window.
Talk time shorter than expected on the first few charges
Li-Polymer cells ship at storage voltage — typically around 3.8V — not at full capacity. A single charge cycle does not bring the cell to its rated 900mAh immediately. Usable capacity builds incrementally over the first 3–5 complete cycles as the electrolyte fully wets the electrode structure. If talk time feels short after the first charge, run the pack through at least three full charge-to-cutoff cycles before drawing conclusions about battery health.