Contact Your MSA Rep........
After taking delivery of new MSA packs in May, our MSA rep advised us to contact him if we found our packs wearing out batteries very quickly.
I forget the technical details, but basically MSA had an issue with a batch of integrated PASS devices that caused them to drain batteries very quickly. He made it sound like MSA is aware of this problem and is willing to correct it so contact your MSA rep.
FYI, the rep told us that none of the recent packs are experiencing this problem...it was occurring on packs that were manufactured a year or two ago.
As for our packs, we have had no problems so far.