I have seen many answers online to how much power the USB dongle linked to a wireless mouse uses, but nothing about how much power the actual mouse draws from its batteries. What is a ball-park estimate on how many milliwatts a generic wireless mouse uses when it is being moved, and when it is being idle?
Microsoft did a detailed study of this about ten years ago, so the figures given here will be a little out of date. However modern mice are probably not that much different.
Microsoft was comparing two of their wireless mice against two similar products from Logitech. Unlike a lot of tests, Microsoft built a robotic device that moved the mouse in such a way as to simulate the way a human would use the mouse.
Studies indicate people use mice on average between 4 and 27 hours per week; but in this study the mouse was stimulated by the motion profile for 44 hours. The rest of the time the mice were in a deep sleep.
Actually both brands of mice had three power modes: active, drawing the most current, with motion, then no motion for a brief period, then motion again etc. As already mentioned there is a deep sleep mode, which occurs after about 10 minutes of no activity. There also is a intermediate sleep mode (idle) which is in between the active and deep sleep modes.
The measurements were as follows. Around 30 mice of each type were tested.
Microsoft Wireless Microsoft Wire- Logitech Cord- Logitech Cord- Intellimouse less Optical less Click Plus less Click Active power State 11.7 mA 13.0 mA 23.0 mA 22.4 mA Intermediate Sleep 942 µA 913 µA 1.32 mA 1.31 mA Deep Sleep 157 µA 146 µA 296 µA 293 µA
The tests were run until the batteries (either Energizer or Duracell AA alkalines) fell to 0.8v.
It is interesting to note that for each of the two mice tested per brand, the current consumption was about the same for each of the power modes, indicating the technology used was similar.
Microsoft didn't say how long the batteries lasted, so I made a calculation using the Microsoft mice. Microsoft also didn't say what the split was between the active power state and the idle power state, so I am making the assumption it is about 10 / 90 (10% in active mode, and 90% in idle mode). Given that they were assuming the mice were being used 44 hours per week, and a person is not using a mouse continuously all day long, I think that's reasonable. I'm also using an average between the two Microsoft mice.
Active mode: 12 mAh * 4 hours * 52 weeks = 2496 mAh Intermediate mode: 0.9 mAh * 40 hours * 52 weeks = 1872 mAh Deep sleep mode: 0.150 mAh * 124 hours * 52 weeks = 967 mAh
For a total of 5335 mAh. Given that two AA batteries in parallel provides 5700 mAh, this indicates the batteries will last about a year in normal use. Which matches what I get for my wireless mouse.