Screen resolution changes when entering battery mode

[qyron]

Hi all,
I have a nice brand new W520 laptop with Windows 7 64-bit and fullHD display. Due to my nearsightedness I prefer to work in 1280x720 resolution instead of "native" 1920x1980 resolution. But when I switch to battery mode the resolution falls back to 1080p. There is no resolution-related option in Power Options. Is there some other way to prevent resolution from changing automatically?

Thanks!