After replacing the 1500 mAh batteries with 2600 mAh, $10 for 4 at Wal-Mart, I got 5 to 6 hours of playback with about 50% of that using the FM transmitter. After recharging I only got about an hour out of the new batteries. I swapped out with the other two and again initially got 6 hours followed by only an hour. I put the first two 2600s back in after recharging externally and guess what .. 6 hours. The pattern continues to repeat so I have to point the finger of blame at the backpack for not fully charging the batteries.
I haven't experienced any problem with the battery life in the HD unit.
Your quick response to this post: (0 total votes) I agree (0%) I disagree (0%)