Nexus 7 Tablet Install for Dummies (Guide)

I don't have to piggyback or cut anything. See here: http://legacygt.com/forums/showthread.php?t=268062

Subbing for further guide.

Anyone have an issue where the tablet randomly discharges the battery in matter of hours?

 

Sent from my SM-N950U using Tapatalk

Anyone have an issue where the tablet randomly discharges the battery in matter of hours?

 

Sent from my SM-N950U using Tapatalk

 

It's not going to deep sleep, you've got some sort of wakelock. Diagnosing that can be anywhere from "oh, it's this" to "I have no idea and I never will," so.... best of luck

 

If you go to the battery menu (on anything after KitKat, I believe, you can get it from swiping down from the top of the screen twice, then tapping the battery icon), it'll show you the time the tablet has been "awake." If it's awake when the screen is off for extended periods of time, the problem is a wakelock from an app. I have a Tasker script that closes all apps that I use in my car's N7 (music app, Waze, BtSsm, etc...), turns off bluetooth and WiFi, and locks the screen when it loses power. I haven't had any issues with wakelocks, but I've been really careful with my tablet install as far as the ROM and kernel as well as all the apps that I've installed on it.

Mine went through this for a number of months, but in the last 2-3 it's only happened once. It's a tricky thing to figure out. I kept seeing just enough current through my USB power to keep it from deep sleep, so I wired a kill switch inline to straight up kill the power to help force a consistent deep sleep.

My setup on my exLegacy:

 

JDM frame

Asus Nexus 2013 Wifi (battery removed) with external Power and Volume controls

Running Timur's ROM

USB hub powered OTG

USB-Optical sound converter

Custom power supply (with external MiFi Router charger algorythm) and custom powering (battery emulator), hot start within 7 hours after last ride, keeping power on for 14 seconds after ignition off (helpful to keep it working when car restarts).

Could you elaborate on the power supply setup?

 

I had initially planned on building basically a good power supply and OTG on a circuit board to insure max power for charging and running the tablet. I might still do that at the begin during building/testing.

 

But it seems like the no battery mod might be better with the only main issue I see is that sometimes the tablet thinks it's charging while on battery power, or so I've seen reported.

 

For the issue of cranking I plan to run both IGN and ACC with diodes to the DC converter. And for shut down I plan to build a RAP (retained accessory power) which will retain ACC for the entire car. based on a few things so I don't need a time delay like you have done.

Any of you all run elementalx instead of timurs kernel? It looks like it supports newer version of Android.

 

Just picked up a 2013 LET Nexus 7 for $60 and have a navi bezel on the way.

Here's something maybe some of you can help with.

When i turn the key back to turn off the car and keep the radio on, the tablet stays powered. But when i crank the engine over, it immediately dips to suspend mode and then aborts - which kills a lot of my apps, and the scanned music database for my thumb drive.

 

Is there a way to bypass this - like let it count down for a few seconds before the suspend countdown starts so that if i'm just restarting my engine it doesn't freak out the tablet?

I faced that problem too. So I've been using a timer just like this one:

 

http://timers.shop/Multi-Functional-5V-20V-Time-Delay-Relay-Timer-5-amp_p_12.html

Two diodes is better... I guess I shouldn't say better but different. But it is they way I did it and I consider it better.

 

Run both ACC and IGN to the positive of your 12v to 5v adapter and put a diode on each wire.

 

Read here

Edited April 5, 2018 by nevets27

What I like about the timer is that it also helps when you shut off the car and you inadvertently put the key in the off position, while still wanting to use the tablet. By the time you realize that you should have left the key at the ACC notch, it may be too late (especially for the usb peripherals). Kind of annoying.

I can't remember, but I think I set my timer to 15sec.

Ah, fair point. Going to have the RAP solve that issue for me. Edited April 5, 2018 by nevets27

Could you elaborate on the power supply setup?

 

I had initially planned on building basically a good power supply and OTG on a circuit board to insure max power for charging and running the tablet. I might still do that at the begin during building/testing.

 

But it seems like the no battery mod might be better with the only main issue I see is that sometimes the tablet thinks it's charging while on battery power, or so I've seen reported.

 

For the issue of cranking I plan to run both IGN and ACC with diodes to the DC converter. And for shut down I plan to build a RAP (retained accessory power) which will retain ACC for the entire car. based on a few things so I don't need a time delay like you have done.

 

I haven't engineered the power supply myself. I just told how it should work and it's a black box for me. All I know it's based on Arduino which controls several RC DC DC converters. I went a long path with this power supply and paid a lot for it as did not know that Nexus 2013 car power supplies are manufactured by android enthusiasts for silly money.

Two diodes is better... I guess I shouldn't say better but different. But it is they way I did it and I consider it better.

 

Run both ACC and IGN to the positive of your 12v to 5v adapter and put a diode on each wire.

 

Read here

Very helpful - I was hoping for a software solution to be honest - I'm not too keen on rewiring my car, especially since i don't have direct access to it all the time. It sits in a "public" garage, and doing any kind of work on it is laborious.

Where did you place your power supply? If you do choose the timer router, it is very easy to install. Three wires IIRC, that's it. You don't need a relay as long as the load is under 5A. I've been using mine for like 2 years now. Zero issue.

My N7 configuration is a royal PITA :spin::mad:

 

Got stuck right after the Android 6.0.1 factory image MOB30X (flo) installation.

No more connection in the bootloader so can't install the TWRP recovery and superSU. (even with unplugging the cable)

 

Best part is it shut down due to low battery

Strange. Didn't you carefully follow Timur steps described here:

 

If somehow you were able to clear the 'dalvik cache', it might fix your issue

I'm going to venture to guess either the timer or the diodes will require the exact same amount of wires.

 

Timer will need to have power during cranking which is removed during during cranking on the ACC line. Therefore it needs IGN or Constant also.

 

Diode uses ACC and IGN. So you'll need both regardless. How is your tablet powered currently? If its hardwired for power now then you are already more then half way there. If you are just using a cigarette plug adapter then its a bit different.

 

FYI, ACC, IGN and 12v Constant (battery) are all already at the cubby. In my case (09 without nav) the clock plug has all that you need.

 

A wiring harness that plugs into that I'm sure would be nice. Could build that quite easily, anyone know a part number for the clock side of the plug?

Can't remember exactly where I got the constant power. I think it is from one of the wires from the back of the HVAC/AUDIO unit. Not bad really.

And yeah, I do have a separate (small) 12-5V power supply for the tablet and peripherals.

My N7 configuration is a royal PITA :spin::mad:

 

Got stuck right after the Android 6.0.1 factory image MOB30X (flo) installation.

No more connection in the bootloader so can't install the TWRP recovery and superSU. (even with unplugging the cable)

 

Best part is it shut down due to low battery

 

Well you should definitely start with a full battery. But either way shouldn't be an issue. Charge it up and get into bootloader, I doubt you killed the ability to get into bootloader.

I haven't engineered the power supply myself. I just told how it should work and it's a black box for me. All I know it's based on Arduino which controls several RC DC DC converters. I went a long path with this power supply and paid a lot for it as did not know that Nexus 2013 car power supplies are manufactured by android enthusiasts for silly money.

 

Could you tell us the name of it or a link to it? I'm curious about it.

Could you tell us the name of it or a link to it? I'm curious about it.

 

I asked the guy, will share his contacts later to pm.

Where did you place your power supply? If you do choose the timer router, it is very easy to install. Three wires IIRC, that's it. You don't need a relay as long as the load is under 5A. I've been using mine for like 2 years now. Zero issue.

 

I just ran a USB cable through the center console to the cubby, and am using a cigarette lighter power port. Makes it easy to disconnect when I'm only backing up the car and don't need it to power up.

I installed a little switch on the inside of the console by the driver's seat to cut the power from the accessory convertor I have under the console. This allows me to decide when to power the N7. I'm going to put in the timer as well to help with ECU resets. When I reset, there are times that the engine cuts out when learning the fuel tables. This will muck up the N7 something fierce.