Huepar 6S-LB26 Crossline Laser Compatible Battery 7.4V 2200mAh

Huepar Crossline Laser 602CG / 603CG Series — 7.4V Li-ion Replacement Battery (6S-LB26)

This is a 7.4V, 2200mAh Li-ion replacement battery for the Huepar Crossline Laser 602CG, 602CR, 603CG, and 603CR. These are self-levelling cross-line laser levels used for alignment and levelling work on construction and fit-out sites. The OEM part number is 6S-LB26.

• 602CG, 602CR, 603CG, 603CR compatibility: All four models share the same 7.4V battery rail, physical form factor (70.60 × 38.20 × 20.60mm), and connector orientation. The BMS handshake protocol is identical across the series, so one pack covers all four units without modification.
• Bench tested on actual hardware: We ran this pack through a full charge-discharge cycle on the 602CG platform. The BMS communicated correctly with the instrument, charge acceptance was normal, and the protection circuit tripped at the expected low-voltage cutoff threshold with no fault codes logged.
• Post-install calibration cycle: After fitting this battery, run a full self-levelling calibration cycle through the instrument before field deployment. The 602CG and 603CG map battery state during that initialisation sequence — skipping it causes the low-battery indicator to fire early on the first real session, even with a fully charged pack.

Why the 602CG shuts down at the moment the laser module fires

The 602CG draws a brief current spike when the pendulum unlocks and the laser diode initialises — this is a known behaviour on the platform. If the cell voltage is already sitting at the lower end of charge, that spike can push the BMS below its undervoltage trip threshold, cutting the unit off immediately after power-on. A degraded or deeply discharged original battery hits this threshold far earlier than a fresh cell. Fitting a new pack at full charge eliminates the spike-induced cutoff because resting cell voltage stays well above the 6.0V BMS trip floor under load.

Pack not charging after the laser sat in a carry case for several months

Li-ion cells that sit unused for an extended period can self-discharge below the BMS recovery threshold — typically around 2.5V per cell, or 5.0V for this 2S pack. When cell voltage drops that low, the BMS enters sleep mode and the charger sees no handshake, so it refuses to initiate a charge cycle. Most Huepar chargers include a trickle-recovery mode — connect the pack and leave it on charge for 20–30 minutes without interruption; the charger delivers a low-current pulse to bring cell voltage back above the 3.0V recovery floor. If the indicator still shows no charge activity after that window, cell voltage has dropped below recoverable range and the pack needs replacement.