Thanks.
I was probably over thinking it. At first, I guessed there wasn't a battery because there's no address or settings to remember. Then, I was wondering about how it would "keep alive"? So I started thinking there might be some battery.
The manual that came with it says they're good for about 5 years or more. Some of mine are ten years old. I wonder if not being used is better or worse on it?
Funny to me is they look like 2 single AA's that would be in a solar light or something.
Guys are big on BCR's but I had one engine that wouldn't charge it well. Left me second guessing whether to keep swapping them out.