Hi,
We use Defib Dashboard for our R, X and AED's. We are replacing the AED batteries 2 to 2.5 years. Our defibs self test and upload once a week. Batteries get replaced at 25% when we get a notification from Defib Dashboard on-site but off-site we will replace two yearly regardless of the capacity to save travelling out. These are also monitored on Defib Dashboard. Some are sitting on top of crash trollies, some in grab bags and others in metal AED boxes. I allow 2% decrease in capacity every 4 weeks for monitoring stock levels.
If for any reason the defib does not upload it tries for approximately three minutes to upload and get server acknowledgement. If your server software is not on the lastest version there are occasions when AED's can upload multiple times in the three minute window. This had been rectified in the last Defib Dashboard release. If you're on Device Dashboard you will not have to worry about that.
Have those that have been replaced between 1 and 2 years been in active use (you have around 140 200J shocks) therefore depleting the battery? If you download the full log you can view it with a text editor and you will see every time the device is switched on, self tests and clinical use.
I have also seen staff switching the devices on to check them (2J self test performed automatically each time), we advise only check the readiness indicator and that the pads are in date.