BatteryBar Pro. I also found that I save over 2000 mW when not using the type cover. Adds about another hour. I have a nice BT keyboard I was going test but can't find it.
Thanks! BatteryBar is an awesome little utility. It's a must have for any SP4 owner that wants to squeeze extra hours out of a battery charge.
The most useful data item is current battery drain rate. My usage rate bounces around between about 4,000 to 12,000 mW. That's a very wide range. Based on my calculations that results in battery life ranging from 3.25 hours to 13.00 hours. Here are the inbetween numbers:
Battery
Drain................Battery
Rate (mW)....Time (hours)
12,000...............3.25
11,000...............3.55
10,000..............3.90
9,000................4.33
8,000................4.88
7,000.................5.57
6,000................6.50
5,000................7.80
4,000................9.75
3,000...............13.00
The way to use BatteryBar is to make changes to your setup (e.g., turn down the brightness, close an application, turn off a live tile, etc.) and then see what that does to your current battery drain rate. You'll probably be surprised at what's costing you battery power and what's not.