Battery not lasting very long

I purchased the Euro-Pro about 1 month ago and did as the directions stated. I left it on the charger base for 20 hours then used it. I've drained it of battery at least 5 times and my charge lasts for only 10 minutes before it starts losing power. I just read a review stating that the directions are wrong and you are not to leave it on the charger base for that long, and it will actually drain and render the battery useless very quickly! AAAAAAGGGHHH!! I just drained battery (after 10 minutes) and I will charge it for no more than 9 hours then take it off the base. Hopefully this will resolve the problem and I will get a much longer charge. Everything else about the vac is excellent. Its picks up everything, including pet hair, and is not heavy or cumbersome. Other than the battery problem, I love it!