About this replacement
Stihl Cordless Shrub and Grass Shears — 10.8V Li-ion Replacement Battery
This is a 10.8V, 2500mAh lithium-ion replacement battery for the Stihl HSA 25 cordless shrub and grass shears. The HSA 25 is a handheld landscaping tool used for trimming hedges and cutting grass edges. Part number 45154006500 confirms direct fitment for the models listed below.
- HSA 25 compatibility: The HSA 25 and HSA 25 Cordless Shrub and Grass Shears share the same 10.8V power rail, battery connector, and BMS handshake — one battery fits all three variants.
- Bench tested on actual hardware: We ran full charge/discharge cycles on this cell — the BMS held voltage steady under cutting load and triggered the low-voltage cutoff cleanly without drop-off or thermal fault.
- First charge after storage: Li-ion cells ship partially charged. Run a full charge before first use to let the BMS calibrate state-of-charge correctly — this improves capacity accuracy over time.
Why the 10.8V rail matters for shear blade performance
The HSA 25 blade motor is tuned to a 10.8V nominal input. Voltage sag under load directly affects blade speed and cut quality. A healthy cell with a functioning BMS maintains voltage closer to the nominal rating during cutting bursts. Capacity at 2500mAh gives the cell enough headroom to handle repeated short cutting cycles without hitting the low-voltage cutoff prematurely.
Shears losing power mid-cut — what causes it and how to fix it
If the HSA 25 slows noticeably during a cut and then recovers at rest, the BMS is triggering a temporary overcurrent response — not a dead battery. This usually means the existing cells have degraded and can no longer sustain current demand under blade load. Fitting a fresh 2500mAh cell restores the current headroom the motor needs. If the new battery shows the same symptom, check the blade for debris or binding, which increases motor draw.