If you go with the Garmin 64. Dont buy the garmin rechargeable battery pack. Buy rechargeable Panasonic Enerloop batteries. They last me all day and for the price of the Garmin battery pack (That doesnt have the best reviews) I got 4 rechargable Enerloops that will last 1.5 to 2 days depending on what your doing. You can also get the Garmin to recharge them for you with a little scotch tape and an old credit card instead of using a separate battery charger.