Charge circuitry can easily maintain a ±0.05V voltage tolerance if needed. For example, googling for datasheets found this charge controller IC with 1% toleranc

Charge circuitry can easily maintain a ±0.05V voltage tolerance if needed. For example, googling for datasheets found this charge controller IC with 1% tolerance: http://cds.linear.com/docs/en/datasheet/4050f.pdf http://cds.linear.com/docs/en/datasheet/4050f.pdf I'm no expert on battery chargers, but I can certainly imagine a design using that kind of tolerance if it made the batteries work better; holding that kind of tolerance is fairly cheap these days. Re: glitches, I'd imagine that a battery isn't going to care about extremely short duration events; preventing longer-duration overshoots isn't all that hard.