# Nexus - Dashboard installation - Power supply problem



## MRaksa (Nov 29, 2015)

He everybody,

I try to assemble Nexus 7 2012 3G into toyota avensis t25 dashboard.

I want that Nexus to power on automatically when I turn on the ignition and power off also automatically when I put the key out.
So, I have rooted Nexus and installed Timur's Kernel. I read that there is an option which makes it possible by detecting voltage in usb wire (assuming there is a li ion battery connected, right?). At this point a doubt appears.
I read about li-ion batteries and it is suggested for safety reasons to keep and use the battery in specific range of temprrature. For example, li-ion battery schouldn't be charged below 0C degrees and schouldn't be exposed to temperatures above approximately 50C degrees. 
So, I prefer to put out the battery and supply power directly from cigarette lighter's wire (12v/5v transformator between), but I don't know whether it will function as I described at the beginning ?
Could someone give me any good piece of advice ?


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## -=Jeff=- (Jan 31, 2014)

http://forum.xda-developers.com/showthread.php?p=64128641#post64128641

Look at post #19


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