Change Battery Pack Error Message

I bought a couple of T3is recently and one of them has a weird problem where, after firing a few shots, it'll get a message telling me to change the batteries even though the batteries are fresh. I've tried other batteries and it still exhibits the same problem. None of my other cameras have this problem.

The camera is a month old and I haven't been able to use it because of this problem. Has anyone experienced this and know a way to fix it? Thanks!

You use the term "batteries"(plural). are you using a grip? If so, try removing it and test the camera again.

Rrblint offers good advice but if you aren't using a grip, then the charger is suspect assuming I you are using the same charger for all batteries. Do you have a voltmeter to check a fully charged battery? It should read about 7.3 volts as I recall. Maybe a friend with another charger that can be used as a test.

What brand batteries by the way?