I use this all the time with the bulk batteries from Costco. My gut also says the bounce effect is a little too sensitive, as I've had batteries have a good bo

I use this all the time with the bulk batteries from Costco. My gut also says the bounce effect is a little too sensitive, as I've had batteries have a good bounce even when the device they're is still able to pull some juice out. But a fresh battery will 100% not bounce. It's the simplest thing to do when you're changing the batteries in something and you got the old/new batteries mixed up.