Hi Andy,
User maintenance:
No, Lange Flugzeugbau does not endorse users playing
around with the battery pack. What kind of maintenance
you would want to perform is also unclear to me. Howerver,
removing a battery pack and exchanging single batttery
modules is a simple task which takes little time when
performed by a trained individual.

Battery price:
The price of a full battery pack is an academic issue.
As pointed out; by the time you will need to replace
the pack, the price of the pack will be a very different
one. I am however, rather sure the price will not have
climbed. Furthermore, by then you should have climbed
3.600.000 m (11.811.024 ft) under power, and flown
some 228.000 km (123.110 n miles) in sawtooth flight,
assuming no nasty thermals have decided to interfere.

Andor