Answer nowadays is quite a lot!
Here are the non-rechargable batteries we're using on the trip.
They are mostly for our SatMap GPS which will be used all day, everyday and so needs approx 10 AA lithium batteries per week. This gives us complete 1:50000 OS mapping of the UK and records every detail of the route.
Also needed are a number of smaller AAA lithium batteries to power the tiny pump used to blow up our beds every night!
None of these can be sent off with other items in the parcels we are making up to be sent of to friends for later retrieval en route - they are classified as prohibited items by the Royal Mail so we'll be carrying quite a few at a time!
