The Duracell CopperTop battery received the highest marks for use in a flashlight, according to ConsumerSearch. The rechargeable Powerex Imedion battery was also recommended, as of 2014.
All alkaline batteries tested either good or very good when used in flashlights, but the Duracell CopperTop lasted longer than average. The battery has a guaranteed shelf life of 10 years due to its DuraLock Power Preserve Technology and was also cited for its affordability.
The Powerex Imedion received high grades for being the only low self-discharge, rechargeable battery that is available in every standard size, including 9-volt. The product is also an adequate choice for a flashlight, because it holds its charge extremely well in storage. For flashlights, alkaline batteries are a better value than the more expensive lithium versions.