JCB Toughphone Tradesman 2 Compatible Battery 3.7V 1200mAh

JCB Toughphone Tradesman 2 — 3.7V Li-ion Replacement Battery (300D006018F)

This is a 3.7V, 1200mAh Li-ion replacement battery for the JCB Toughphone Tradesman 2 (TP127). It fits the same connector and footprint as the original 300D006018F cell. If your Tradesman 2 shuts down unexpectedly, loses charge quickly, or won't power on, this is the direct cell replacement.

• Toughphone Tradesman 2 / TP127 fitment: All three model names — Tradesman 2, Tradesman Two, and TP127 — refer to the same handset. They share an identical battery bay, connector pinout, and BMS handshake protocol, so one cell covers all variants.
• Bench tested on actual hardware: We ran the 300D006018F replacement through full charge and load cycles on the TP127 platform. The BMS accepted the cell without a protection-trip fault, and the charge IC completed a full CC/CV cycle cleanly.
• Fuel gauge recalibration on first use: After installing this cell, disable fast charging and run one complete discharge down to auto-shutdown, then charge to 100% uninterrupted. This gives the fuel gauge IC a clean reference curve for the new cell before high-current charging begins.

Sudden shutdown at 20–30% on the Tradesman 2 after a cell swap

The Tradesman 2 is built for site use — screen brightness, GPS, and LTE modem all draw current simultaneously under normal conditions. A new cell with an uncalibrated fuel gauge IC can report 25% remaining while the actual cell voltage has already dropped below the BMS cutoff threshold under that combined load. The phone shuts off not because the cell is faulty, but because the fuel gauge is still mapped to the old cell's discharge curve. One full discharge-recharge cycle resets the coulomb counter and resolves this.

Phone not turning on after the replacement battery sat in storage

Li-ion cells self-discharge during storage. If the 300D006018F cell has dropped below approximately 2.5V per cell, the BMS enters a lockout state and blocks normal charging to prevent damage. The phone will show no charge indicator and appear completely dead. Connect it to a wall charger — not a PC USB port — and leave it for 20–30 minutes without pressing the power button. The charge IC will trickle current into the cell until voltage recovers above the BMS re-enable threshold, typically around 2.9V, at which point normal charging resumes.