Mild warmth is ordinary; a tool or supply that becomes hot is not, and the first thing to check is whether the charger output matches what the machine expects.
Charging generates a little heat by nature.
What is worth investigating: a supply that is hot to hold, a tool that is hot rather than warm, or a smell. In each case, unplug first and check the output figure printed on the supply against the figure printed on the tool.
A mismatched third-party charger is the most likely cause after a lost original, and it is why every page on this site that covers a replacement charger leads with the voltage.
If the supply is correct and the tool still runs hot, that is a fault. On a machine under warranty, that is the moment to use it.
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