thanks to Nadeemk I was able to solve this problem
please read this first http://code.google.c...es/detail?id=93
in my case I am working actually with twrp 22.214.171.124 and CM9
1 boot into recovery and make a full backup
2. start your phone
3 download the malez recovery with the img for acer ferrari. http://code.google.c...ri.img&can=2&q=
4 flash the acer ferrari recovery onto your phone.
5 with the acer tools you flash the binfile you find it in the original solution of Nakeemk
6 after the flashing you boot the phone make sure that the usb debug mode is enabled in your settings menu
7 flash the twrp recovery(in my case) back on your phone
8 shutdown the phone
9 boot into recovery
10 restore previous made backup just restore the backup without wiping anything!!
11 reboot the system and your battery status should be correctly shown