4.8V HR-4/5AU Wolf Garten Hedge Trimmer Replacement Battery

My Wolf Garten Accu 60 cuts fine for a few seconds then the blades slow down and almost stop — is the battery dying or is something wrong with the shears?

That stuttering-then-stalling pattern on NiMH packs is almost always voltage sag — the cells can't hold their voltage under the brief but sharp current spike the blade motor demands, especially if the pack has been shallow-cycled repeatedly over one or two seasons. Before assuming the battery is dead, fully charge it and then run the shears on open air with nothing to cut: if the blades still bog under light load, the pack has lost its ability to deliver current, not just capacity. We see this constantly on 4.8V NiMH packs that have never been run fully flat. Charge the new pack completely, then use the shears until they stop on their own before recharging — that first full discharge cycle matters.

I charged my replacement HR-4/5AU overnight and the shears feel weaker than my old battery did even when that one was half dead — what's going on?

NiMH cells that sit in a warehouse develop a partial charge memory and often need two or three full charge-discharge cycles before they reach their rated capacity. The pack you received was likely stored at a partial state of charge, which is normal for NiMH during shipping and storage, but it means the first charge rarely delivers full capacity. Run the shears to cutoff, charge fully, and repeat that cycle twice more — most packs recover to their true capacity by the third cycle. If the shears still feel noticeably weak after three cycles, check that the battery contacts on the tool are clean and making firm contact, as oxidised pins on older Accu 60 units are a common culprit.

My Wolf Garten charger light never turns green — it's been on the new battery for hours and just stays red, what does that mean?

A charger that stays on a constant red or fault indication without switching off usually means it isn't seeing the voltage rise it expects from a healthy NiMH pack — this happens when cells arrive deeply discharged below the charger's detection threshold. Try removing the battery, waiting 30 seconds, and reseating it firmly to rule out a contact issue first. If the fault light persists, measure the pack voltage at the contacts with a multimeter: a fully discharged but recoverable 4.8V NiMH pack should read somewhere above 3.5V — anything below that means the cells dropped too low for the charger to accept. Some OEM Wolf Garten chargers have a narrow acceptance window, so if the pack is borderline, a brief warm-up in a warm room (not hot) can bring the resting voltage up enough for the charger to recognise it and begin charging normally.