Oh, yeah, just search the store for "Battery". There are a ton of them available, many for free. Just keep in mind that some app makers want to get data like "Phone Identity", "Owner Identity", "Data Services", "Location Services", etc. That said there is one called "Battery Tile" (completely free) that doesn't require access to all that info (although many of the ones that require the personal information have the ability to display battery life in the lock screen). Battery Tile | Windows Phone Apps+Games Store (United States)
That is probably not the app maker itself that wants that data, just the ad control inside the app or the ability to mail the log results if you need them.