My dad bought my son an early birthday gift: Little Experimenter Telescope for Kids. The telescope’s best feature is a projector that mounts to the top of the telescope and projects pictures of stars, planets, satellites, and space shuttles. My son loves it and has been playing with it ever since he got it.
The projector is powered by three tiny watch batteries. They burned out quickly. I don’t have a huge stock of watch batteries at the house and I loath buying them. I do have a bunch of 5V power banks that I have collected from tradeshows and conferences from days gone by. For our weekend “science” project, I busted out the soldering iron and an old USB cable. Three watch batteries are 4.5V. A USB power bank is 5V. That’s close? I tried it. Nothing smoked. Nothing exploded. My son helped with applying a liberal amount of solder flux to the battery connectors. I added strain relief to the cable and put it back together. Now, the Little Experimenter Telescope’s projector can be powered from a rechargeable USB power bank.
Based on my experience so far servicing kid’s toys, I think they should all be rechargeable or have a USB plug. We go through a lot of batteries and watch batteries are the worst.