Gardena 18V 1500mAh Li-Ion Hedge Trimmer Replacement Battery

My Gardena hedge trimmer cuts fine for a few minutes then the blades just stop mid-session — battery still shows charged

This is thermal cutoff triggering early, and it's more common on Li-ion packs that have developed cell imbalance from shallow cycling — plugging in after every short use without ever running the pack down properly. The trimmer's protection circuit reads uneven cell voltages as an overheat or over-discharge risk and kills the output before the indicator catches up. Let the replacement pack run down fully on its first two cycles before recharging, then check whether the cutout moves later into the session.

Replaced the battery and now the trimmer feels weaker than it used to — blades are spinning but struggling through thicker growth

An 18V Li-ion at 1500mAh is a relatively modest capacity pack, and if the new battery's resting voltage is correct but sags under load, the trimmer's motor won't reach full torque. We've seen this on bench when a cell group inside the pack is underperforming — the pack reads fine at rest but drops below 15V under cutting load. Charge the replacement fully, then test it on light material first; if it feels slow even there, put a multimeter on the pack terminals while the trigger is held and check whether voltage drops sharply below 16V.

Gardena HeartBeat charger just blinks continuously and won't start charging the new battery

The HeartBeat system charger runs a handshake check with the battery's onboard protection circuit before it begins charging — if the pack has arrived deeply discharged from storage, the charger can reject it as faulty rather than recover it. Leave the battery connected to the charger for 10–15 minutes without interrupting it; some units will begin a trickle recovery cycle before switching to normal charge. If the blink pattern doesn't change at all after that, check whether the pack voltage reads above 12V with a multimeter — anything lower means the cells have dropped below the charger's recovery threshold and the pack needs to be returned.