SlimBatteryMonitor is described as 'displays a battery meter in the menu bar for laptop and UPS batteries. It uses the same information as Apple's system gauge, but allows you much more control over how the information is displayed. It can take up less space. Works with Mac OS X 10'. There are six alternatives to SlimBatteryMonitor for Mac. The best alternative is CoconutBattery 3, which is free. Other great apps like SlimBatteryMonitor are Battery Indicator (Paid), Battery Health (Free), Battery Health Monitor (Free) and Battery Logger (Paid).
With Battery Health, you can easily see all the important information about your MacBook's battery, such as current charge level, battery capacity, power usage, number of times it has been charged and much more.