I don't like to waste batteries either, but as many of us who work in live theater and music have learned over the years, with rechargeable or partially used batteries it's not worth ruining a show over a 50 cent battery. The "premium" batteries - ProCells, etc - are also not worth the money, IMO. Just get cheap Costco or Sam's Club batteries. They only have to last 2 1/2 hours. Then use them next time for soundchecks or testing or in your bicycle lights.