Newberry, your battery is just fine. Unfortunately, whatever battery time the manufactures of all airplanes claim is always twice what you will actually see. The nice thing about the slope diver is that you can cut the motor off and glide for quite awhile before turning it back on the gain altitude again. I get a good 10-15 minutes of flight if I do it well enough. Also, you can try using the full power to take off and then run the motor at a slower speed to keep it level in the air.... that can make it last longer. Full speed also last 4.5 minutes on my plane just like you found.

The instructions do say to charge the battery for 3 hours THE FIRST time which made my battery extremely hot as well. This is probably too long. I charge about 2 hours per batty now and it's pretty warm when done (and it's not normally fully discharged since the ESC shuts down the motor). Let me know how that new charger works out.... I might need to get me one!