Einhell BT-CD 10.8/3 LI Replacement Battery 10.8V 2500mAh

Einhell BT-CD 10.8/3 LI — 10.8V Li-ion Replacement Battery (4513377E)

This is a 10.8V, 2500mAh Li-ion replacement battery for the Einhell BT-CD 10.8/3 LI cordless drill-driver. It slots into the same battery bay and uses the same connector as the original pack. Capacity is 2500mAh (27Wh) — matching the stock specification.

• BT-CD 10.8/3 LI platform fit: The BT-CD 10.8/3 LI runs a 10.8V rail with a proprietary slide-in connector and a BMS handshake that checks cell voltage before the tool powers on. This pack meets that handshake requirement and holds the correct voltage range the drill expects at startup.
• Bench tested on actual hardware: We cycled this pack through repeated trigger pulls on a BT-CD 10.8/3 LI, monitoring cell voltage under motor-start inrush loads. The BMS held protection thresholds correctly and did not trip on standard torque applications.
• Motor-start break-in on first use: On first use, run the drill at half load for two cycles before applying maximum torque. This gives the BMS time to profile the motor inrush current draw and set accurate overcurrent protection thresholds for your specific drill unit.

BMS cutoff on motor-start inrush in the BT-CD 10.8/3 LI

When you pull the trigger on a cordless drill, the motor draws a brief current spike — often two to three times the running current — before it reaches speed. On a 10.8V pack, that spike is more pronounced relative to cell capacity than on higher-voltage platforms. A freshly installed or returned-from-storage pack may have a slightly elevated internal resistance, which amplifies the voltage sag during that spike. If the BMS interprets the sag as an overcurrent fault, it cuts power instantly. Running two break-in cycles at light load normalises internal resistance and reduces false BMS trips.

Charger not recognising the pack after storage

Li-ion cells that have sat unused for several months can drop below the charger's acceptance voltage threshold — typically around 2.5V per cell. The Einhell charger will blink an error or simply not begin a charge cycle when it detects cell voltage below that threshold. This is a BMS-level protection, not a charger fault. To recover the pack, place it in the charger and wait up to five minutes — some chargers apply a slow trickle to bring cells above 2.8V per cell before switching to normal charge mode.