Hi Mark, very sorry for the long delay in getting back to you, finding the time sometimes can be difficult. Thanks for the kind words, glad you enjoyed the episode, am still trying to find the time to do part 2, hopefully won't be too much longer.

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Hi pokey, again very sorry for the long delay in getting back to you
To answer you 1st question:-

A lead acid battery consists of lead electrode and one side and lead oxide at the other, lead oxides don't normally conduct electricity. Apparently it was only in 2011 that we figured out how it was working. When electrons travel between the electrodes the lead oxide looses oxygen transforming itself into a conductor.

Hope this answer question

Sounds like your also a bit of a battery fan, just goes to show that batteries can last for years (if you look after them).  Had a look at the Mintyboost, sounds very interesting, I would imagine it will be very handy :)