BatteryCare is a free software to monitor performance of your laptop battery. Normally most of the laptops come with some sort of battery information, but the information is basic and most of the times optimization options are missing.
BatteryCare addresses these issues. It continually monitors your laptop battery. Apart from that, it also shows the time left for discharge, and shows it in both percentage as well as exact time.
Apart from Battery statistics, it also continously monitor CPU temperature and shows it. This is a useful info as high CPU temperatures drain the laptop battery faster.
To test this software, I installed it on a laptop that had a bad battery. The inbuilt software of that laptop always showed discharge time as a few hours, even though battery would drain out in around 30 minutes. When I installed BatteryCare, it started giving me the exact discharge percentage, exact rate of discharge, and exact time remaining. That was great.
Apart from this, BatteryCare has some advanced options to automatically select power plan based on whether laptop is running off battery or direct power. BatteryCare can also show other information about laptop battery, such as wear level, capacities, consumption, manufacturer, etc.
I really liked this software for its ease of use, its utility, and the fact that it is totally free. Download using links at the end.