As with all equipment that is used a lot, battery-powered brush cutters also wear out. If the scythe can no longer provide the performance for which it is needed, this can have several causes.
The blade inside the pruner could have become dull from too much use. If this is the case, you need to sharpen it again. You can do this yourself. To do this, first remove the cutter from the brush cutter (it is best to remove the battery first to avoid injury). Then the blade can be sharpened with a grindstone or circular saw.
If the brush cutter is equipped with a string and stops cutting, it may simply be because the reel has run out. So all you have to do is disassemble the head and insert a new pulley.
However, if it is not the cutting head that is causing your machine to stop producing the expected result, it is quite possible that the built-in battery is no longer working. With most brush cutters, the battery can be easily replaced.