HILTI B12/2.6 Laser Meter Replacement Battery 10.8V 2500mAh

HILTI PM 40-MG / PR 30-HVS A12 Series — 10.8V Li-ion Replacement Battery (B12/2.6)

This is a 10.8V, 2500mAh (27Wh) Li-ion battery for HILTI laser distance meters and rotating laser levels in the A12 platform. It fits the PM 40-MG, PR 2-HS A12, PR 30-HVS A12, PR 30-HVSG A12, and twelve additional models sharing the same battery slot and communication protocol. OEM part numbers B12/2.6, B12/4.0, and 2077977 all cross-reference to this pack.

• A12 platform compatibility: These models share a common 10.8V rail, identical slide-in connector footprint, and the same BMS handshake sequence. Any variation in the battery's authentication response causes the device to display a fault and refuse to power on — this pack matches that handshake exactly.
• Bench tested on actual hardware: We cycled this pack on a PR 30-HVS A12 and a PM 40-MG. The BMS held the 10.8V rail steady across both devices, completed the authentication without fault codes, and accepted a full charge cycle from a HILTI C 4/36-DC charger without interruption.
• Laser calibration and cell voltage: On the PM 40-MG and PR-series levels, the internal levelling motor draws a short inrush burst at startup. Keep the battery above 20% charge before powering the rotating head — the BMS will trip on underpowered inrush, which can interrupt a calibration sequence mid-cycle and force a full restart.

BMS cutoff on PR 30-series levelling motor start surge

The PR 30-HVS A12 and PR 30-HVSG A12 use a self-levelling motor that pulls a short inrush current spike at power-on. If the battery's state of charge is low or the cells have aged, the BMS reads this spike as an overcurrent event and cuts output before the head finishes levelling. The result is an abrupt shutdown with no error code — the device simply goes dark. A fully charged pack with healthy cells absorbs the inrush without triggering the overcurrent threshold, which sits around the 10A transient mark on this platform.

Charger blinking red on a new or stored A12 pack

HILTI C-series chargers reject packs where individual cell voltage has dropped below approximately 2.5V per cell — a common state after extended storage. The charger blinks red and never transitions to a charge cycle. To recover the pack, some HILTI chargers include a boost or reconditioning mode; engage that mode and hold for up to 10 minutes until cell voltage climbs above the 2.8V acceptance threshold. If the charger has no boost mode, a short trickle charge from a compatible bench supply at 0.1C will bring the cells above the acceptance floor before handing off to the standard charger.