I picked up a set of older Ryobi One+ tools (blue that originally came with nicads) the other day with no batteries. I have a couple of newer tools (green) with Lithium Ion batteries. The weirdest thing is that when properly seated the batteries don't power the older tools, but when not quite fully inserted they work fine (but drop out if you let go). I thought it might be an issue of corrosion on the inside of the old tools but it looks fine. All else being even these should be interchangeable. Any suggestions.