After reading the report on PLB it has come to my attention that the McMurdo PLB plus has a replaceble battery pack. The picture on the report shows what apperars to be simply seven AA lithium batteries connected in series. This picture can be found on page 84 of the second report or appendix 3

Is this true?
Is it possible to carry AA batteries as a backup battery pack for the PLB?

McMurdo sells a user replacement battery for about 90 usd.

I will be purchasing my first PLB within the next two weeks so any ideas you have will be welcome.