My current means of powering things is USB rechargable batteries. I have a about five of them that range between small 3000-5000mah ones to a big 20000mah interstate battery jump starter pack. Is there a device that lets me add all their power together into a centeral power source so I don’t have to keep swapping them out?
You can still just crack open the banks and wire the cells together in parallel or series (depending on your needs), then hook them up to one of the controllers. I bet they’re just a bunch of 18650s
Sure, but you probably shouldn’t build a DIY battery pack out of salvaged 18650s of varying brands, capacities, and conditions unless you really know what you’re doing because that’s dangerous if you get it wrong.