Hilti B12/2.6 10.8V Laser Level Replacement Battery 1500mAh

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

This 10.8V 1500mAh Li-ion battery replaces the HILTI B12/2.6 and compatible OEM packs across the PM 40-MG, PR 2-HS A12, PR 30-HVS A12, and PR 30-HVSG A12 laser level series. It slots into the same battery bay and connects to the same BMS handshake circuit the original pack used. Capacity is 1500mAh (16.2Wh) — confirmed from product data, not estimated.

• PM 40-MG and PR-series compatibility: These models share the same 10.8V lithium-ion platform, a common multi-pin connector, and the same BMS communication protocol. A single pack covers the full range because the battery management handshake is identical across the series — the charger and tool negotiate state-of-charge using the same data line.
• Bench tested on actual hardware: We cycled this pack through the PM 40-MG's standby and active scan modes, monitoring the BMS cutoff response under low-cell and over-temperature conditions. The protection circuit responded correctly at expected thresholds — no nuisance trips during normal laser operation.
• Laser level storage between site visits: If the tool sits in a van or site box for more than two weeks, store the battery at roughly 40–60% charge. Laser levels draw a small parasitic current from the battery even when off — a fully charged cell left connected will drift into over-discharge territory faster than a pack stored separately.

Charger blinking red on a new 10.8V pack that's been sitting in storage

Li-ion chargers include an acceptance voltage gate — if a cell group has dropped below roughly 2.5V per cell, the charger refuses to begin a charge cycle and signals the fault with a red blink. This is common with packs that have been stored discharged for several months. Some HILTI chargers include a recovery or "boost" mode that applies a low-current trickle to bring cells back above the gate voltage. If yours does not, a compatible Li-ion charger with a manual recovery function can pre-charge the pack to 9V total before returning it to the HILTI charger.

Capacity fade after repeated short top-up charges on the job site

Laser levels on active sites get pulled off the charger and put back frequently — often after only a few percent of discharge. Repeated shallow cycling compresses the usable capacity range the BMS has profiled, and the pack begins reporting "full" at a lower actual charge over time. This is a BMS calibration drift, not cell failure. Run two full discharge-and-charge cycles — let the tool run until the low-battery indicator trips, then charge uninterrupted to 100% — to allow the BMS to recalibrate its state-of-charge window back to the full 1500mAh range.