Wolf Garten Accu 80 4.8V Replacement Battery 2000mAh

My Wolf Garten Accu 80 runs for a few seconds then cuts out — is that the battery dying or something else?

At 4.8V Ni-MH, that symptom almost always means the pack has developed one or more dead cells that collapse under load the moment the tool draws current. A resting pack can still show acceptable voltage on a multimeter, then sag immediately once the motor spins — so a resting voltage check alone won't catch it. We see this consistently on aged Ni-MH packs that have been left discharged between seasons. Put a load tester on the pack while it's running; if voltage drops below 3.6V under draw, the pack is the problem.

New replacement battery is fully charged but the Accu 80 feels weaker than it did with the old one — what's going on?

Ni-MH cells need a few full charge-discharge cycles before they reach rated capacity, especially if the replacement pack was stored for any length of time. The cells arrive in a partially discharged, semi-dormant state and won't deliver full torque until they've been properly conditioned. Run two or three complete drain-and-charge cycles before drawing any conclusions about performance. If the tool still feels sluggish after conditioning, check the terminal contacts on the tool for corrosion — a resistive connection causes more voltage drop at 4.8V than most people expect.

Charger light stays green and says it's done but the battery is barely warm — did it actually charge?

A cold pack after a charge cycle on Ni-MH usually means the charger didn't detect a proper negative delta-V peak, so it timed out early or never entered full charge mode at all. This happens when the cells are deeply discharged below the charger's detection threshold — common after a battery sits unused all winter. Try leaving the pack on the charger for a full cycle, then immediately test terminal voltage; a properly charged 4.8V Ni-MH pack should read between 5.4V and 5.8V at rest. If it reads below 5.0V, the pack is too far discharged for the charger to recover it automatically and the cells may be sulfated beyond use.