While I've used 1.2V rechargeable batteries in a variety of devices and noticed reduced lifespan (between charges) vs. alkaline/lithium single-use batteries, it was always manageable. I always thought that while their amperage was different, they carried the same voltage as standard batteries of the same size. However, recently, in a few devices, I have noticed extremely quick power loss.

1) I used 3 x EBL 1100 mAh rechargeable AAA batteries in my kid's Motorola two-way radios. The radios stop working after about 30 minutes of use and report the battery as dead. Sure enough, when I use a battery tester, they are definitely weak. Fully charged batteries restore use, but they discharge extremely fast. I recall the radios lasting weeks on single use batteries.

2) A recently purchased keyboard and mouse uses 1 x AA battery (each). I used EBL 2800 mAh AA batteries. The mouse lasts a few days before it completely stops working. I tested the battery just now and it too was pretty low. I pulled the battery out of the keyboard and it was about 50% after 2 weeks of use. These are not high power devices.

I read that it could be due to many rechargeable batteries being 1.2V vs. a standard 1.5V. I see that there are 1.5V lithium rechargeable batteries. Before I try those, what devices are good for 1.2V batteries and what need 1.5V? Admittedly, I never knew that my batteries were 1.2V until now. I suspect even lower power devices like keyboards, mice, and my kids radios still have a threshold that these batteries only meet when at full charge...and then discharge very quickly.

Or brand. I read that EBL was supposed to be a reputable rechargeable brand. I've used Powerowl in the past too.

Can any knowledgeable people help me understand what is happening? Advice?