Yes. However, using a cheap charger, one that has a timer, can damage the batteries and they always cause them to not last nearly as long. A smart charger measures the voltage among other indicators, to determine when the battery is fully charged. There some really good and/or expensive smart chargers and I have tried a few. Two of my favorites are the Titanium Innovations MD-1600L and the La Crosse BC-500. Both come with a car cigarette plug so it can be used on the go. The MD-1600L also has two USB ports, so I can charge two phones and 16 AA or AAA batteries all at once. Both of these chargers allow you to charge 1 battery at a time or use every slot. I hope this helps someone.
Yes; as long as they are the right size. I use them ( AAA, AA, C, D AND 9 Volt ) in everything; mouse, keyboard, flashlights, smoke detectors, remotes of all kinds and kid's toys. They are great. Last a long time and recharge quickly. You won't be disappointed.