My BTS09 will not take a charge.  When I plug the cable in the red light comes on for about 2 seconds then goes off.  If I leave the cable plugged in the speaker doesn't charge.  I've tried multiple cables and multiple plugs.  When the speaker is turned on and connected to a device, it shuts down in a minute or so.  On my phone it shows a 50% charge that drops to 0% when trying to use the speaker.  Anyone have any suggestions or is the battery gone?  The speaker is about 3.5 to 4 years old.