More than change will be Install a new one since the one that comes by default in LXDE you can't uninstall it, just remove it and put it on your panel. In my case we will use the application FDPOWERMON we install:
When you finish installing it, as root we go to this address / etc / xdg / lxsession / LXDE and we open the autostart file with our text editor. (If you like, you can do it from the terminal with nano or vim.)
And we add to the last line @fdpowermon:
And when we're done we'll have a Battery Monitor prettier. Now we just have to restart or log out and they will have something like this in their panel in the notification area:
DEBIAN + LXDE
Now let me show you how my Debian Testing to LXDE. You will notice that it does not have the Menu (or Home) Button. Instead I put a panel with all the Main Applications. 
Well that was it for today. Give your opinion to see if you like it. It's my first article, so please excuse me. Suggestions are welcome.