Before I had a battery tester, and I have 3 v meters, I threw away good
batteries, could not match pairs and kept bad ones. A battery tester
puts the correct load for each cell so you can determine if it is worth
keeping and for how long. Plus you can match odd cells to the power
left. I saved alot with a battery tester, no more gussing. A bulb will
not be the correct load a V meter will not indicate Life Left.