Birchmeier REC 15 AC1 Compatible Battery 18V 3000mAh Li-ion

Birchmeier REC 15 AC1 Series — 18V Li-ion Replacement Battery (12070301)

This is an 18V 3000mAh (54Wh) lithium-ion battery for the Birchmeier REC 15 and REX 15 sprayer range. It fits the REC 15 AC1, AC2, PC1, REX 15 AC1, and at least nine additional models sharing the same battery platform. The battery powers the onboard pump motor that pressurises liquid for spray application.

• REC 15 / REX 15 platform compatibility: These models share a common 18V battery rail, connector geometry, and BMS handshake protocol. The same pack seats and communicates correctly across the AC1, AC2, PC1, and REX 15 AC1 variants without adapter or modification.
• Bench tested on actual hardware: We cycled this pack under simulated pump-motor load conditions. The BMS held the voltage rail steady through start-up inrush and maintained cutoff thresholds within the expected 18V window across discharge.
• Pump-motor inrush on first cycles: On first use, run the sprayer at low pump demand for two cycles before sustained full-pressure operation. This lets the BMS profile the motor's start-up current draw and calibrate overcurrent thresholds before you push the pump to maximum draw.

BMS cutoff on pump motor start inrush in the REC 15

The REC 15's pump motor draws a brief current spike the moment it starts — this inrush can be two to three times the steady-state draw. A new pack's BMS defaults to a conservative overcurrent threshold until it logs a few charge and discharge cycles. If the sprayer cuts out immediately on trigger, the BMS is tripping on that inrush spike before it recognises it as normal motor behaviour. Running two partial cycles at low pressure trains the BMS to widen the threshold for that startup surge.

Charger not recognising the pack after storage

Li-ion cells stored for more than a few months can drift below the charger's acceptance voltage — typically around 2.5V per cell. The Birchmeier charger will not begin a charge cycle if it reads the pack below that floor, which looks like a dead or unresponsive battery. This is a BMS lockout, not a failed cell. Place the pack in the charger, leave it connected for 20–30 minutes without interruption, and the charger's trickle pre-charge circuit should bring the cells up to acceptance voltage — at which point the charge LED will shift to active status.