Originally Posted by ks1g

DCRainmaker recently described how he gets Open Street Maps onto Garmin units. Process is for the Garmin 705, 800, 810 but may work for other equipment.

GPS with sealed internal rechargable batteries can be made to work - get an external charger (USB output to GPS) that uses AA batteries. Usually marketed to recharge cell phones. You can make one if you have basic soldering skills or know someone with same - look for "MintyBoost". (Kits also from ThinkGeek, Adafruit, and a few other vendors. ~ $20.00)