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Tired of expensive disposable batteries and rechargeable AA suck. So I made a 10k mAh pack for my deadbolt.
(sh.itjust.works)
Eneloops would only last about 3 weeks. And disposable last 2 months. This door is used a lot and since it has Zwave and a door open sensor it sends info on every open.
Bonus, since it can handle the lipo AA batteries that put out 1.8v and it gives the motor more oomph I made the battery pack give 7.2v and it never sticks anymore.
This is a garage-door so its not critical access but is used a lot.
Rechargeable Eneloops are Ni-Mh which makes the nominal voltage 1.2V where as the voltage on an Alkaline battery is 1.5V. The rechargeable ones are worse than normal Alkaline batteries. You can get rechargeable 1.5V Lithium AA batteries from Nitecore. Those are much better than Ni-Mhs.
The only issue with the rechargeable lithium batteries is that their voltage curve is extremely sharp, so they hold the 1.5v right up until they die.
Depending on how the electronics and battery match up, your deadbolt might not be able to warn you about a low battery condition, which might mean you get locked out. I currently have two doors, both with a keypad entry, so it's extremely unlikely they'll both be dead at the same time. If you only have one keypad entry, then you should probably avoid using lithium rechargeable AA's.
fyi there are some Lithium rechargeables that have a "low voltage" indicator, where they drop from 1.5v to around 1.1v when low so that it'll set off any low charge circuit
brand I found is XTAR, but I'm sure there's others
Just my 2c but I have 15 year old Eneloops still going. They do have a lower voltage output which isn't good for certain applications, but they are great for kids toys, remotes, flashlights/headlamps in my experience. Of the probably 60-70 I've bought, the only failures I've had are with the Pros, don't waste money on those. I'll have to check out Nitecore though.