Rechargeable Batteries I Keypad

Generally, yeah, but since they're typically lower voltage than regular batteries you might get low battery indicator sooner. And, of course, the key pad does not charge the batteries so you have that aspect to deal with.

The batteries should last a fair long time. If they're going flat fairly often you'd be better off to sort out why that's happening. Might take a call to SS...

I have used rechargeable batteries (Enloop) in my keypads before and find that they just don't last as long.  I also find that, due to their lower voltage, the keypads exhibit some unusual behavior at times.  Considering the importance of the alarm system and the need for it to operate at 100% efficiency, why take a chance?  It's best to use the Duracell batteries that SimpliSafe recommends.  They can last one to two years depending on how much use the keypads get.  I have three keypads in the house, so a pack of 40 batteries from Costco when they are on sale is a great deal.  It can last me several years, and it is comforting knowing that the system is running at peak efficiency.

I used https://www.amazon.com/gp/product/B07QV8GYV3 Deleepow Rechargeable Lithium/Li-ion AA Batteries, 1.5V 3200 mWh 1500 Cycle AA Rechargeable Batteries 4-Pack which are true 1.5v, not 1.2v like NiMH. I have gone through the first recharge cycle after 5 months, so I'm happy with that. I've had no issues. It will probably last longer now since there has been 2 updates since I purchased in February and was dying in a couple weeks with the recommended batteries. It was dead this morning, so I just used my phone app to deactivate. You always need a backup keypad any ways :)

I'm using these batteries in a Simply Safe SSKP3 keypad. After 2 or 3 cycles they pay for themselves. I'll probably have the alarm system for 3 to 5 years, so 6 to 10 charge cycles and I'll still have the batteries for another 500-1000 cycles.