And 19 months later, the first part of this experiment comes to a close. Today the contact sensor with the RCR2 battery stopped reporting. It was showing 0% battery for the last week (*), so I knew it’s days were numbered. The other paired contact sensor with the CR2 is still showing 87% battery, but I don’t believe that. I’ll update again when that one dies.
IMHO 19 months for the rechargeable lifetime is pretty great. I have 25 RCRs left to deploy (as I got them just after I bought a 24 pack of CR2s), but I’m happy enough that I’ll probably buy 40 more when I’ve deployed all those. (I have about 80 Iris sensors that use CR2s).
Edit: I just noticed I can subscribe&save the batteries for 5% off. I’ll do that and buy 8 a month for a few months.
(*) in the future I will recharge the RCR2s before they completely die. I only did that for this test one.