Hello Dan,
I was in the same situation as you. Bought an eXplorist 500 LE, and I have found out quickly, that the three AAA batteries
lasts only 4-5 hours.
I far as I know, the battery type which fits into Magellan eXplorist is SNN5582B (SNN5582A is 750mAh only) which is 1100mA. The same unit such is used in the 'Motorola T720/T730' cellphone.
I was looking at higher capacity so I have bought on eBay from seller 'vl1066'
- Magellan eXplorist rechergeable Li-Ion battery 1350mA (!) $15
- power cable for car 12V cigarette lighter $12
- Magellan eXplorist Bike Handlebar Mount Bracket $22
This battery lasts as a hell, with medium backlight you can count with 15 hours, (+ keep 3xAAA as backup).
I have an 12v battery at home (diving light) so I can recharge the GPS even at home and outdoors.
You have an option to buy USB recharge cable.
idiver