[Q] Nexus 7 in car

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Ted_rivers

New member
Jul 6, 2010
4
0
Hi, I have recently installed my Nexus 7 (running CM10.2 on 4.3.1 and leanKernel) in the dashboard of my car. I installed a cigarette socket behind that dash that provides power to the device when the vehicle is running. When the vehicle turns on i have tasker set to lock the display on, start my music and torque. The problem I am having is when the N7 is one and receiving a charge the battery is still discharging (approx. .8%/h according to battery stats app). I have used 3 different charges, two which are 2.1A and the third is 150w dc 12v to 110v ac power inverter which i have used 2 different usb chargers in, but i am still seeing the battery discharge while I am using the tablet. i can rewire the cigarette socket so it is constantly charging the device but since I am not able to reach the power button on the tablet i dont know how ill be able to toggle the screen. i have tried to under-clock the cpu and gpu (currently have the device running on 1 core) but still havent seen an improvement. Any idea what i may be able to do to rectify the problem?

I was also going to try to upgrade the tablet to 4.4.2 but adb and fastboot cannot see the tablet anymore. i updated the usb drives and it was working perfectly fine up until a week ago so i am not sure what is happening.

Thanks for the help.
 

furious84

Senior Member
Aug 26, 2010
82
5
spilimbergo (pn) italy
Hi, I have recently installed my Nexus 7 (running CM10.2 on 4.3.1 and leanKernel) in the dashboard of my car. I installed a cigarette socket behind that dash that provides power to the device when the vehicle is running. When the vehicle turns on i have tasker set to lock the display on, start my music and torque. The problem I am having is when the N7 is one and receiving a charge the battery is still discharging (approx. .8%/h according to battery stats app). I have used 3 different charges, two which are 2.1A and the third is 150w dc 12v to 110v ac power inverter which i have used 2 different usb chargers in, but i am still seeing the battery discharge while I am using the tablet. i can rewire the cigarette socket so it is constantly charging the device but since I am not able to reach the power button on the tablet i dont know how ill be able to toggle the screen. i have tried to under-clock the cpu and gpu (currently have the device running on 1 core) but still havent seen an improvement. Any idea what i may be able to do to rectify the problem?

I was also going to try to upgrade the tablet to 4.4.2 but adb and fastboot cannot see the tablet anymore. i updated the usb drives and it was working perfectly fine up until a week ago so i am not sure what is happening.

Thanks for the help.

Hi, do you have a dcdc-usb? I know Who did your work (n7 in dash car) normaly have that, with a otg-y cable and normaly use USB ROM with Timur's kernel, which is a dedicated rom for car 's installation. Try to search info about that.
Unfortunatelly development is stopped to android 4.2 (the release before 4.3) But it' s very good rom.
If your installation is fixed, in the night u will lost about 1-2 %
Ps can you upload some photoes about your dash :)?

Inviato dal mio Nexus 7 utilizzando Tapatalk
 
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Ted_rivers

New member
Jul 6, 2010
4
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Hi, do you have a dcdc-usb? I know Who did your work (n7 in dash car) normaly have that, with a otg-y cable and normaly use USB ROM with Timur's kernel, which is a dedicated rom for car 's installation. Try to search info about that.
Unfortunatelly development is stopped to android 4.2 (the release before 4.3) But it' s very good rom.
If your installation is fixed, in the night u will lost about 1-2 %
Ps can you upload some photoes about your dash :)?

Inviato dal mio Nexus 7 utilizzando Tapatalk

I dont have a dcdc-usb as the power to the tablet is coming from 2.1A car charger or a 150w power inverter. i dont have a otg-y cable but i do have the means to easily install one if i ever need it. I never knew about USB rom and Timur's kernel. ill flash those asap and hopefully that will fix the battery drain. As for pictures i only have this one from when i first installed the the tablet but know i have my dashboard disassembled. hopefully this will hold you over for now :).
 

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ryar

Member
Mar 4, 2009
13
0
Ted, you need to flash a kernel that supports fast charge and enable it. I have the same issue, after flashing a 4.4 rom I lost my fast charge and over the duration of a long drive the battery is discharged. Apps such as fanco kernel updater have the option to enable fastcharge, if the kernel supports it. Great setup BTW, I have mine mounted on the dash.
 

Ted_rivers

New member
Jul 6, 2010
4
0
Ted, you need to flash a kernel that supports fast charge and enable it. I have the same issue, after flashing a 4.4 rom I lost my fast charge and over the duration of a long drive the battery is discharged. Apps such as fanco kernel updater have the option to enable fastcharge, if the kernel supports it. Great setup BTW, I have mine mounted on the dash.

Hi ryar,
Thanks for the help. I've flashed a few different kernels that have fast charging enabled. The latest is Timur's kernel which says fast charging is enabled. Sadly my tablet is still discharging when its in use so I've decided I'm going to have it set to charge at all time and use a magnet to switch the screen on when I need it.
 

b3ltazar

Senior Member
Jun 21, 2010
508
144
42
syracuse ny
Hi ryar,
Thanks for the help. I've flashed a few different kernels that have fast charging enabled. The latest is Timur's kernel which says fast charging is enabled. Sadly my tablet is still discharging when its in use so I've decided I'm going to have it set to charge at all time and use a magnet to switch the screen on when I need it.

Are you trying to charge in host mode or just using the USB came that came with the nexus 7? I could help you solder power and volume to some switches so you can toggle screen on off that way? I bought a Samsung branded car charger and it works great for car charging. I made a y cable that you can turn host mode on and off with a switch. I could help talk you through it or do it for u if you buy the stuff its pretty cheap fairly simple to do if u have patients. Most of Those 2.1 amp dual port chargers only supply 1 amp to android devices, this could be your problem.
 

Ted_rivers

New member
Jul 6, 2010
4
0
Are you trying to charge in host mode or just using the USB came that came with the nexus 7? I could help you solder power and volume to some switches so you can toggle screen on off that way? I bought a Samsung branded car charger and it works great for car charging. I made a y cable that you can turn host mode on and off with a switch. I could help talk you through it or do it for u if you buy the stuff its pretty cheap fairly simple to do if u have patients. Most of Those 2.1 amp dual port chargers only supply 1 amp to android devices, this could be your problem.


I am just charging the tablet straight up no host mode. ive used a variety of chargers: two different branded 2.1a chargers and both the stock nexus 7 wall charger and another tablet wall charger plugged into a 150w power inverter. Thank you for the offers! If its fairly simple to solder the power switch I would prefer to do that regardless of the discharging problem so that i can hard reset the tablet if i ever need to.

Thank you for the help!
 

furious84

Senior Member
Aug 26, 2010
82
5
spilimbergo (pn) italy
Hi ryar,
Thanks for the help. I've flashed a few different kernels that have fast charging enabled. The latest is Timur's kernel which says fast charging is enabled. Sadly my tablet is still discharging when its in use so I've decided I'm going to have it set to charge at all time and use a magnet to switch the screen on when I need it.

Fast charging on Timur's rom work with otg Y Cable

Inviato dal mio Nexus 7 utilizzando Tapatalk
 

dimex

Senior Member
Nov 28, 2012
768
148
The problem I am having is when the N7 is one and receiving a charge the battery is still discharging (approx. .8%/h according to battery stats app). I have used 3 different charges, two which are 2.1A and the third is 150w dc 12v to 110v ac power inverter which i have used 2 different usb chargers in, but i am still seeing the battery discharge...

I've had my Nexus 7 "in my truck since last year. I at first had it sleep via Tasker, but I was having issues if I left my car for awhile. The batterywwould be low and if I didn't have long drives, I could never rechargeit to ssufficient battery fullness.

I changed my setup to have the tablet power on upon receiving AC ignitionpower using this adb command:

there is a Fastboot command that you can issue to the bootloader to make the tablet power on once plugged it.* “fastboot oem off-mode-charge 0” makes the unit power on the instant its connected to AC. “fastboot oem off-mode-charge 1” returns to normal state,* so fitting an external switch isn’t 100% necessary, but i decided i wanted one anyway. I’m using Tasker to switch the unit on and off* with the ignition, but having the external switch is a handy addition.

Then I have Tasker turn it off after minute not being used. I'm sure it's not good for the Nexus 7 to always be at 100% power, but I don't care about the batter health because I purchased this for my truck only.

My only concern now, is the safety of the battery in AZ summer heat. I don'twant it to explode, and iI'm wondering if the tablet will function with AC power only, then I could remove the battery and not worry about it.
 

furious84

Senior Member
Aug 26, 2010
82
5
spilimbergo (pn) italy
I've had my Nexus 7 "in my truck since last year. I at first had it sleep via Tasker, but I was having issues if I left my car for awhile. The batterywwould be low and if I didn't have long drives, I could never rechargeit to ssufficient battery fullness.

I changed my setup to have the tablet power on upon receiving AC ignitionpower using this adb command:



Then I have Tasker turn it off after minute not being used. I'm sure it's not good for the Nexus 7 to always be at 100% power, but I don't care about the batter health because I purchased this for my truck only.

My only concern now, is the safety of the battery in AZ summer heat. I don'twant it to explode, and iI'm wondering if the tablet will function with AC power only, then I could remove the battery and not worry about it.

How are about temperature there? How is your setup into truck? I mean n7 is into the Dash? Or You have some support? Anyway maybe your technical questions will be better answering on developer forum (If You have installed usb rom by timur)

Inviato dal mio Nexus 7 utilizzando Tapatalk
 

dimex

Senior Member
Nov 28, 2012
768
148
How are about temperature there? How is your setup into truck? I mean n7 is into the Dash? Or You have some support? Anyway maybe your technical questions will be better answering on developer forum (If You have installed usb rom by timur)

Inviato dal mio Nexus 7 utilizzando Tapatalk

The temperature gets to almost 120F (48.8C) in the summer, and that's outside the vehicle. I took a dremel to my dash and modified it to mount the nexus 7. It's clean and looks just about stock. I made a wooden box to the dimensions of double DIN, and put the mounting brackets on either side. I used sticky tape to mount a nexus 7 matte black case to the front of the box, so when I slide the box into the double din area it lines it up perfectly. Then I just snapped the dash back into place over the top of the Nexus 7. So, the tablet is basically built into my truck.
 
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furious84

Senior Member
Aug 26, 2010
82
5
spilimbergo (pn) italy
The temperature gets to almost 120F (48.8C) in the summer, and that's outside the vehicle. I took a dremel to my dash and modified it to mount the nexus 7. It's clean and looks just about stock. I made a wooden box to the dimensions of double DIN, and put the mounting brackets on either side. I used sticky tape to mount a nexus 7 matte black case to the front of the box, so when I slide the box into the double din area it lines it up perfectly. Then I just snapped the dash back into place over the top of the Nexus 7. So, the tablet is basically built into my truck.

I saw photoes after i posted :).
48C wow.... In italy it s hard when there are 35...

Inviato dal mio Nexus 7 utilizzando Tapatalk
 

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    Hi, I have recently installed my Nexus 7 (running CM10.2 on 4.3.1 and leanKernel) in the dashboard of my car. I installed a cigarette socket behind that dash that provides power to the device when the vehicle is running. When the vehicle turns on i have tasker set to lock the display on, start my music and torque. The problem I am having is when the N7 is one and receiving a charge the battery is still discharging (approx. .8%/h according to battery stats app). I have used 3 different charges, two which are 2.1A and the third is 150w dc 12v to 110v ac power inverter which i have used 2 different usb chargers in, but i am still seeing the battery discharge while I am using the tablet. i can rewire the cigarette socket so it is constantly charging the device but since I am not able to reach the power button on the tablet i dont know how ill be able to toggle the screen. i have tried to under-clock the cpu and gpu (currently have the device running on 1 core) but still havent seen an improvement. Any idea what i may be able to do to rectify the problem?

    I was also going to try to upgrade the tablet to 4.4.2 but adb and fastboot cannot see the tablet anymore. i updated the usb drives and it was working perfectly fine up until a week ago so i am not sure what is happening.

    Thanks for the help.

    Hi, do you have a dcdc-usb? I know Who did your work (n7 in dash car) normaly have that, with a otg-y cable and normaly use USB ROM with Timur's kernel, which is a dedicated rom for car 's installation. Try to search info about that.
    Unfortunatelly development is stopped to android 4.2 (the release before 4.3) But it' s very good rom.
    If your installation is fixed, in the night u will lost about 1-2 %
    Ps can you upload some photoes about your dash :)?

    Inviato dal mio Nexus 7 utilizzando Tapatalk
    1
    How are about temperature there? How is your setup into truck? I mean n7 is into the Dash? Or You have some support? Anyway maybe your technical questions will be better answering on developer forum (If You have installed usb rom by timur)

    Inviato dal mio Nexus 7 utilizzando Tapatalk

    The temperature gets to almost 120F (48.8C) in the summer, and that's outside the vehicle. I took a dremel to my dash and modified it to mount the nexus 7. It's clean and looks just about stock. I made a wooden box to the dimensions of double DIN, and put the mounting brackets on either side. I used sticky tape to mount a nexus 7 matte black case to the front of the box, so when I slide the box into the double din area it lines it up perfectly. Then I just snapped the dash back into place over the top of the Nexus 7. So, the tablet is basically built into my truck.