What does it mean if a 2001 VW Beetle stops and the battery symbol shows?
The red battery symbol indicates that there is a problem with
the charging system.
It could be the alternator (faulty), voltage regulator (old),
bad battery (old). or a blown fuse.
If possible, after checking the fuses, you may have to recharge
the battery overnight and then drive the vehicle to an automotive
store (a close one) that can test the suspected equipment. I say
this because it is near impossible to remove the alternator on a
2001 beetle (I had the same problem) and could not remove it myself
to take in for testing, due to the tight space of its location and
the other systems that were blocking access to the 2 bolts.
If the alternator tests good, look at replacing the voltage
regulator. The alternator can still be putting out the correct
amount of charge and be good, but if the regulator goes out it may
not show on the test. The voltage regulator is a small voltage
sensor with brushes in it...should be around $75