Gardena Accu90 7.2V Grass Shears Replacement Battery 3000mAh

My Gardena grass shears cut fine for a few passes then suddenly stop mid-trim — is the battery dying or is something else wrong?

That cut-out pattern on Ni-MH at 7.2V is almost always thermal protection triggering, not a dead cell — the pack heats up under continuous load and the tool shuts itself off before damage occurs. It happens faster on older packs because aged Ni-MH cells build internal resistance, which turns more energy into heat instead of torque. Let the shears cool for 10 minutes, then try again — if they restart and cut-out again at roughly the same point, the pack has degraded past the point where cooling alone fixes it. Check resting voltage after a full charge: a healthy 7.2V Ni-MH should read between 8.4V and 8.6V with a multimeter; anything below 7.8V at rest confirms the pack needs replacement.

I charged my Gardena 8820 shears all night and they feel weaker than before — how is that possible?

Ni-MH chemistry is genuinely vulnerable to overcharging, and leaving the tool on charge overnight repeatedly causes a condition called voltage depression, where the cells lose capacity in a measurable, progressive way. It's not a charger fault light or a dead battery — the pack accepts charge and reads normal, but available cutting power is reduced. This is the failure mode most people miss because the shears still turn on and appear functional. To partially recover the pack, run it completely flat, charge it fully, and repeat that cycle two or three times — if capacity doesn't recover after conditioning, the cells are past recovery and the pack needs replacing.

The blades on my Gardena grass shears are spinning but barely cutting through anything — could this be a battery issue or is it the blade?

Before pulling the blade, check voltage under load: a 7.2V Ni-MH pack that sags below 6V the moment the motor engages is causing the weak cut, not a dull blade. Voltage sag under load is a classic sign of high internal resistance in aged Ni-MH cells — the pack looks charged at rest but collapses as soon as current demand rises. Handheld grass shears draw relatively low current compared to heavier garden tools, so this symptom often shows up gradually and gets blamed on blade condition for months before the battery is suspected. Clip a multimeter across the terminals while squeezing the trigger and watch the voltage — if it drops more than 1V instantly, the pack is the problem.