How long do AAA batteries last in an OmniPod PDM?

The answer to this question has subtly haunted me for years.

My PDM is the only device in my diabetes management kit that actually runs on batteries. Everything else, such as my Dexcom receiver and my blood sugar meter, can be recharged, which is highly preferable over batteries. But until I make the transition to the OmniPod DASH system (which uses a rechargeable lithium battery in lieu of AAA batteries), I’m stuck with replacing the AAAs in my PDM whenever they drain.

But it was never overly clear to me…how do I actually know when the batteries are out of juice?

There’s a battery icon on my PDM, of course, that shows roughly how much life my batteries have left in them. When new batteries are put into the PDM, it shows a fully charged battery. Some time after that, the battery icon is half full, and then after more time, it goes down to a tiny sliver to indicate the batteries are running low.

Ever since I became an OmniPod user, I always assumed that the batteries had to be replaced as soon as the display ran down to that itty bit of battery life. I just figured that was the signal. Plus, I didn’t want to run the risk of delivering a bolus or changing my pod only for my PDM to completely die halfway through, leaving me to figure out how much insulin I had left to deliver – or worse, with a pod not fully activated that I’d have to scrap.

For a long time, though, I’ve been wondering if I’ve been changing the batteries prematurely. Maybe they had more life past that little sliver. So I put my theory to the test: Last month, my PDM displayed the low battery icon. Instead of changing the batteries immediately, I decided to wait and see what would happen.

And I can report that my batteries did last much longer after that initial low battery icon appeared. In fact, they lasted an addition 7-8 pod changes (I lost track after the first handful). I was pleasantly surprised to discover that my PDM could make it almost an additional month past that first indication of a low battery! And even better, I learned that the system does give a warning that makes it crystal clear when the batteries should be changed: The battery icon goes from having a tiny bit of life left to a flashing display showing a completely empty battery. I forget what the exact message was on my PDM, but I also got a system notification telling me to change my batteries soon.

I wish I remembered exactly when I changed the batteries last, but if memory serves me correctly, then it was sometime in November. So the AAA batteries in my OmniPod PDM lasted roughly three months.

Not too shabby, and now I know exactly when I can expect to change my PDM batteries.