I want to power a small 3V LED blinky device for a week or so. Normally it runs off watch batteries, so I tried building a little flashlight-like container to hold it and a couple of AAA batteries. Maybe not too surprisingly, it starts to fade significantly in a day or so. After a couple months it's still blinking, but I'd much rather it have a shorter, brighter life.
How can I use say, 3 AAA batteries to guarantee that the thing will run at full brightness as long as possible? The blinky light is very close to the diameter of the batteries, so of course I'd like something that could fit into the same tube. For that matter it would be OK to have it pulse at full brightness with 2 batteries as long as it doesn't take too long to charge up.