Wolf Garten Power 60 3.7V Cordless Hedge Shear Replacement Battery

My Wolf Garten hedge shears start cutting then slow down halfway through a thick branch — is that the battery dying or the tool?

That's voltage sag under load — a known behaviour in 3.7V single-cell Li-ion packs when the cells have aged or weren't fully charged before use. The shear's motor draws a short, sharp current spike on tough stems, and a degraded cell can't hold voltage through it, so the tool throttles back as a protection response. Charge the pack fully, then check the open-circuit voltage with a multimeter immediately after — a healthy cell should read at or above 4.1V; anything below 3.9V at rest points to a worn cell that won't recover under load. If the reading is low, the cell needs replacing, not the charger.

I put the new Wolf Garten battery in the charger and nothing happened — no lights, no beep, nothing

A completely flat Li-ion cell can drop below the charger's detection threshold, usually around 2.5V, and the charger simply won't initiate a charge cycle because it can't confirm a valid cell is present. This happens most often with a battery that sat in storage for an extended period before being used. Check the cell voltage directly with a multimeter — if it reads below 2.5V, some chargers have a "wake" or recovery mode; if yours doesn't, a brief trickle from a compatible Li-ion charger set to its lowest current can bring the cell back into range. Once it reads above 2.8V, the standard charger should recognise it and begin a normal cycle.

Wolf Garten hedge trimmer stops after a few cuts and then works fine again after sitting for a minute

That pattern — cut, stop, rest, recover — is a thermal cutoff cycling on and off, not a dead battery. The protection circuit inside the cell shuts the pack down when it detects heat above the safe threshold, then resets once the cell cools. On compact single-cell 3.7V packs like this one, it happens faster in warm weather or when the blade is blunt and the motor is working harder than it should. Sharpen or inspect the blade first, then check whether the behaviour gets worse as ambient temperature rises — if it only happens on hot days with a clean blade, the cell's internal resistance has risen and the pack needs replacement.