Well, I had the same issue when I got mine - the battery didn't last very long - one of the problems is with the android O/S being designed to work on smart PHONES....I found that 70% of my battery was being sucked up by the phone apps, checking for signal strength (which is useless on these devices). I upgraded my O/S to ICS 4.0.3, and got SOME improvement, but by far the best tools I have that have increased my battery life from 2 - 3 hours on my Airpad X, to about 10 hours, are:
1. Download the airplane mode Wi-fi app (free), turn ON airplane mode, then tap the wifi ON button. This has a MAJOR effect on battery life.
2. Download the No-frills CPU Control app (free), and there are 2 settings for speed, and several "governor" settings. I like the performance setting, but if you want your battery to last a lot longer, set it to ondemand, or powersave. Set your max clock speed to the highest speed, and the min. clock speed to the lowest.
This will step down the processor speed while in sleep mode, or running apps that don't require lots of CPU speed, like the kindle or nook e-readers, and will greatly increase your battery life.