I have a smart lock on the front door and very happy with it but about once a year it needs new batteries. It needs four 1.5V AAs but rechargeable ones from the supermarket etc are 1.2V. The non rechargeable ones default to 1.5V but would prefer rechargeable. Quick google says they do exist but certainly not very common.
What is the best way to get these in NZ? Again google found one NZ supplier but it says rechargeable alkaline which makes me think it is a typo. There does appear a few on Amazon. Don't mind paying extra for quality.