[iPad] What's up with the beeping noise?

 

I was traveling with my husband when my iPad battery got pretty low. I plugged my iPad into his iPhone car charger and it seemed to be charging. After a few moments on the charger, My iPad sterted emitting this annoying "BBLING" noise every 5 seconds. Last time I heard this sound was from hubby's iPhone when it wouldn't take a charge. Anyone know why it was blinging?

Cherié----Sent from my iPad

__._,_.___
Recent Activity:
.

__,_._,___