This pretty much means a bad battery or charger. It's sometimes charger related, especially if the charger is old enough to have Dell molded into the top part of the enclosure. If your charger is one of these, find a newer one with a blank enclosure with the DP/N 0VJCH5. If this doesn't fix it, you have to replace the battery.
The older chargers are known to do this from time to time, which is why Dell updated it with a newer unit. The 0VJCH5 unit seems to be reliable, compared to the previous chargers. If for some reason you can't replace the charger yet, unplug it once in a while and see if that clears the problem up. This is what worked for me while Dell was shipping my new unit when I complained about this problem. It's related to the sense line, since these chargers use a 8 pin IC, generally. These IC's sometimes have bit rot issues or outright fail. If the charger responds to my workaround, it's intermittent or bit rot. If that doesn't help, the sense IC is bad. This only seems to happen a lot on the 130W unit, so the 65W adapters seem to be less troublesome.
If the machine is under warranty and you have the 130W unit, contact Dell and get a new charger, although mine was giving me the unauthenticated charger problem. If you are out of warranty, give this a read: E6540 diagnostic lights
If you reboot the machine and it says it suffered a permanent battery failure, you will need a new battery.