Einhell RG-CH 18 Li Replacement Battery 18V 5000mAh

Einhell RG-CH 18 Li — 18V Li-ion Replacement Battery (RG-CH 18 Li)

This is an 18V Li-ion replacement battery rated at 5000mAh (90Wh) for the Einhell RG-CH 18 Li cordless hedge trimmer. It slots into the same battery bay as the original pack and communicates with the trimmer's onboard BMS over the same connector pinout. Voltage and capacity match the factory specification exactly.

• RG-CH 18 Li platform fit: The RG-CH 18 Li runs an 18V battery rail with a proprietary slide-on connector and a three-wire BMS handshake line. This replacement uses the same connector geometry and communicates the correct cell voltage and temperature data so the trimmer's protection circuit does not flag it as an unrecognised pack.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the RG-CH 18 Li platform. The BMS accepted the pack without fault codes, overcurrent protection tripped correctly on deliberate blade-stall tests, and cell temperatures stayed within spec under sustained cutting loads.
• Motor inrush break-in: On first use, run the trimmer at light cutting load for two full cycles before tackling thick stems or dense hedgerows. This allows the BMS to profile the motor's inrush current draw and set overcurrent thresholds before you push the blade hard.

BMS cutoff on trigger pull during heavy hedge cutting

When the RG-CH 18 Li blade engages dense material, motor inrush current spikes sharply in the first 80–120ms. A new pack with a conservatively calibrated BMS may read that spike as an overcurrent event and cut power before the blade reaches full speed. The fix is to ease into the cut — start the blade in free air, then move into the hedge rather than plunging straight into thick growth. After two or three full working cycles the BMS adjusts its threshold and the false trips stop.

Charger not recognising the pack after extended storage

If the replacement pack has sat uncharged for several months, individual cells can drop below 2.5V — the threshold most Einhell chargers require before entering normal charge mode. The charger light may blink red or show no response at all. Place the pack on the charger and leave it for 20–30 minutes; most Einhell chargers include a trickle pre-charge routine that recovers cells between 1.5V and 2.5V before switching to the main charge cycle. If the charger still shows no response after 30 minutes, check the battery contacts for oxidation and clean them with a dry cloth before retrying.