AA battery powered GPS with maps for long distance
I am planning a long distance ride through northern France this Summer and being a cheapskate, don't want to buy a dynamo hub and USB charging system for a smartphone or a GPS mapping unit. Can anyone recommend a device which I can power using AA (or AAA) batteries but which will let me download decent street maps. Another option would be a smartphone and charge it using a battery pack (again using AA batteries which I can buy en route) - has anyone used a system like this and is it practical (ie how many charges do you get out of a couple of AA batteries)
Many thanks for any advice.