Current delivery and longevity still put C and D cells over AAs, that’s the main reason they are/were common in doorbells. And while 18650s would be equivalent to a C, they would require a charger most people don’t own already, as well as the usual liion safety issues. I’ve heard horrors of folks putting 18650s in to nimh chargers with sprung terminals :/
As for availability, they are certainly very obtainable where I am in UK. Shops and Amazon etc have them.
No issues here in UK. 18650s have high self-discharge rate so are useless for standby applications. AA's are, well, AA's. So you'd have to replace them more often. Not what you want to happen with a door bell.
Current delivery and longevity still put C and D cells over AAs, that’s the main reason they are/were common in doorbells. And while 18650s would be equivalent to a C, they would require a charger most people don’t own already, as well as the usual liion safety issues. I’ve heard horrors of folks putting 18650s in to nimh chargers with sprung terminals :/
As for availability, they are certainly very obtainable where I am in UK. Shops and Amazon etc have them.
No issues here in UK. 18650s have high self-discharge rate so are useless for standby applications. AA's are, well, AA's. So you'd have to replace them more often. Not what you want to happen with a door bell.