Time to replace the battery in one of my PLBs. I called ACR directly and they quoted me $155 and 10-15 day turn around. They went on to say you can do better using one of our authorized service shops and recommended:
Solution One Maritime
Phone: 813-241-6654
Address:
2721 East Adamo Dr
Tampa, FL 33605
Cost for service on my PLB-375 ResQLink+ is $89.99. Turn around time is 3-5 days. They also mentioned to make sure you include your contact info. They will call for payment once the device is done and ready to go out.
Check you expiration dates. Get your PLB serviced if its due.