Are we talking about the re-release Connections? And did you put a new battery in, or was it the original battery that came with it?
Seems like some of the new Connections have battery glitches, or the whole line is just bad with battery usage.
The battery that comes in the package is meant for testing, so it usually has a shorter life than name-brand batteries.
Also, if you weren’t aware, data is saved on Connections, even when the battery dies.