I much more prefer the battery selection from the DP720. The battery (AAA) is more readily available, easy to replace/remove. In a pinch, I could use non-rechargeable batteries if something were to fail on the units on hand. Wouldn’t last long but would have a plan B in the event of failure. How difficult would it be to switch to a system where 3 AAA batteries are used, seeing that the current battery has a voltage output of 3.8v.