I recently purchased a portable DVD player to keep the boy occupied in the car during a trip to MD and at the ballgame, but was a bit dismayed to find that the battery only holds about a 2 hour charge. That is barely the length of one movie, and certainly did not cover the entire trip or even more than a handful of innings.
While out and about, I noticed that even among the more expensive ones I saw that listed a time, those batteries only hold for about 2.5 hours.
I used the cigarette lighter adapter on the ride back, but there are some situations coming up where alternate power sources are needed. Can I buy a battery that holds a longer charge, or are there some inexpensive models (<$150ish) that hold longer charges?