Usually a cell at the end of its life, but check the charger first: a supply with the wrong output can appear to charge while delivering very little.
Three things to eliminate, in order.
The supply. Compare the output printed on it with the figure printed on the tool. A mismatched third-party charger is the commonest cause after a lost original.
The contacts. On stand-charged tools, wipe both the tool’s contacts and the stand’s. Product residue insulates.
The cable. Intermittent charging when the cable is moved means the strands have broken where the cable enters the plug.
If all three are sound, the cell has aged. On most household grooming tools it is not replaceable, which is usually the end of the machine — unless it also runs plugged in, and several clippers here do.
Check your own manual before you follow anything here. Temperatures, water ratings and supply voltages differ from model to model, and the maker’s own figures take precedence over anything written on this site. A supply of the wrong voltage is a failure rather than a slow charge, and the figure is printed on the tool — not inferred from a connector that happens to fit.
Last reviewed August 22, 2026