My In-Dash Nexus 7 Project

[Monkey]

I've finally finished making a custom USB OTG Y cable and prelim charging results are very promising. I will give it a test with torque tomorrow, as that seemed to be the big battery drainer. WIFI etc worked while holding a 100% charge for host mode.

EDIT:

For those that haven't read through the whole topic, I had issues with the current carrying capacity of the OTG Y cables that I was trying from ebay. This included ones that claimed they could charge on the go. They did not. Seeing as I was running a heavy gauge USB cable (purchased from ergotron a 20/24G cable) I knew the bottle neck for the current was at the Y cable. The cable I've made myself is a Y with 20G power and 24G data cores so there's no issue with charging on the go.

I couldn't be happier that i've finally got this thing to work. Buying the cables from the cheap chinese vendors on ebay was getting tedious when they would not work.

Back to great quality audio!

Anyway.....

I realise that these charging Y cables may be hard to come by. So I'm willing to make them for anyone that wants them.

At the moment I'm looking to charge around the $30 mark posted, for something that is guaranteed to work. It won't be the prettiest cable you've ever seen (although it'll be heat shrunk etc to tidy things up) but it will work. The terminals on the USB plugs you get, to say they're tiny is an understatement, so these things take time.

All joints soldered and all terminals hot glued to prevent them wiggling free.

If anyone is interested just shoot me a PM. I'll probably make a few over the next week or so and throw em up in the for sale section.

Thank you to everyone that helped with their info throughout this! Much appreciated!

G

I got my Schoche 2.4A + 2.4A charger today from the UK and still no luck, can't get above about 1050mA charge even with both plugged into a USB OTG hub I bought. I think the cables are the bottleneck. Are you still considering selling these?

[phly]

CurrentWidget works well. I'm not yet running a hub, and I've read that the 2013 Nexus is more efficient and charges much quicker. Currently I'm getting 1% charge every 2 mins with everything on. But the discharge over night is more than 1% per hour in deep sleep. I believe 1500mA charge would mean my charge rate exceeds the discharge rate and I could complete the install.

1% per hour discharge while sleeping seems pretty high, i reckon you should take a look at whats draining the battery while sleeping.

Im running stock lollipop on nexus 7 2013. Ive been checking my battery discharge while the tablet sleeps the last 2 weeks and can get the battery to discharge 5% every 24 hours which i reckon might still be a bit high for me as I dont use my car regularly.

The main things I found you need to disable to prevent discharge are:
- wifi
- bluetooth
- location
- google profile auto-sync
- turn interrupt mode to none

You can use the Tasker app to automate most things. Since your device is rooted, you could download the Secure Settings plugin for Tasker to turn on airplane mode also and possibly some other stuff which I havent explored as my device isnt rooted.

[Monkey]

CurrentWidget works well. I'm not yet running a hub, and I've read that the 2013 Nexus is more efficient and charges much quicker. Currently I'm getting 1% charge every 2 mins with everything on. But the discharge over night is more than 1% per hour in deep sleep. I believe 1500mA charge would mean my charge rate exceeds the discharge rate and I could complete the install.

1% per hour discharge while sleeping seems pretty high, i reckon you should take a look at whats draining the battery while sleeping.

Im running stock lollipop on nexus 7 2013. Ive been checking my battery discharge while the tablet sleeps the last 2 weeks and can get the battery to discharge 5% every 24 hours which i reckon might still be a bit high for me as I dont use my car regularly.

The main things I found you need to disable to prevent discharge are:
- wifi
- bluetooth
- location
- google profile auto-sync
- turn interrupt mode to none

You can use the Tasker app to automate most things. Since your device is rooted, you could download the Secure Settings plugin for Tasker to turn on airplane mode also and possibly some other stuff which I havent explored as my device isnt rooted.

Cheers for your reply! Timur's kernel already activates airplane mode when it goes into deep sleep, which means BT,wifi & GPS are deactivated. I was reading some posts on his Reddit forum and others have suggested that there is a slight discharge through the power source (eg. cig lighter plug) and/or the DAC when not charging. This makes sense I think, because pre-rooting, my 100% stock Nexus 7 2013 with no connections and wifi & BT on lost only a few % per day with screen off (not in sleep mode). I installed Greenify yesterday per BBB's suggestion - will check that out too, but I think it's probably duplicating what Timur's already does.

Do you have some pics of your install? I thought I was the only one to use a N7 2013.
Are you using a DAC (eg. UCA202)? Were you able to move the charging port to the outside of the casing? I opened mine up but it looked like it was hard wired, and not on a ribbon cable like the N7 2012.
So I had to cut a hole into the side of the air vent for the charging cable, and it has restricted movement of the passenger side vent.

I'd like to use Tasker, but it seems hard and I don't have the time to devote to learning it.

For anyone interested in my charging issue, I received my Scosche Revolt 2.4A + 2.4A car charger yesterday. This is one of the most powerful cig lighter to USB chargers you can buy.
I plugged both outlets into a 3 port OTG USB hub (https://www.jbhifi.com.au/computers-tab ... er/510298/) via 2 x USB male A to USB male A cables (http://www.jaycar.com.au/productView.asp?ID=WC7704), thereby giving a theoretical charge input of over 4A with both plugs used. According to CurrentWidget, the highest I achieved was just over 1000mA. Charge rates were about the same with the original Nexus charge cable connected to one of the Revolt's ports. Which is also about the same connected to the original 1.35A Nexus wall charger. This is a really disappointing result as I was hoping for 1500mA or higher. I assume that (1) either the Nexus itself is charge-limited at 1A; or (2) either the OTG hub and/or the USB cables are limiting charge rates.
I found a thread yesterday which discussed voltage as being a limiter, and that you needed 4.9V+ to get over 1A charge. CurrentWidget was showing about 3.8 - 4V. Given the output of USB chargers is supposed to be 5V I'm not sure why this would be lower, other than perhaps my cords may be too long(?)

I'm searching for a solution to get faster charge / slower discharge before I complete the install. I'm also planning to do a removable install by using magnets to hold in the Nexus.

[bigBADbenny]

Nexus Gen3 auto power-on: if usb charger connected, even if battery is empty and device is off link proved...
Uses a 12v-5v DC buck converter for power supply...
http://forum.xda-developers.com/showthr ... ?t=2103183

Magnetic bezel idea:
http://forum.xda-developers.com/showthr ... ?t=2431808

Wireless charging for 2013 Nexus 7 ?
https://www.google.com/search?q=wireles ... ing+Nexus7

Another interesting setup
http://forum.xda-developers.com/showthr ... ?t=2657308

Asking how-to:
http://rootzwiki.com/topic/81906-nexus- ... head-unit/

Another:
http://forum.e46fanatics.com/showthread.php?p=16127894

I suggest you tackle one item at a time, starting with a robust DC power supply, then basic Tasker tasks and profiles, then auto-on Tasker script and so on.
Tasker can be as simple as cut n pasting something that worked for someone else, via the backup/restore function in settings.
Its time consuming but fun too.

Antother suggestion: shorten your cables as much as possible once you get it all setup properly.

[phly]

Cheers for your reply! Timur's kernel already activates airplane mode when it goes into deep sleep, which means BT,wifi & GPS are deactivated. I was reading some posts on his Reddit forum and others have suggested that there is a slight discharge through the power source (eg. cig lighter plug) and/or the DAC when not charging. This makes sense I think, because pre-rooting, my 100% stock Nexus 7 2013 with no connections and wifi & BT on lost only a few % per day with screen off (not in sleep mode). I installed Greenify yesterday per BBB's suggestion - will check that out too, but I think it's probably duplicating what Timur's already does.

Do you have some pics of your install? I thought I was the only one to use a N7 2013.
Are you using a DAC (eg. UCA202)? Were you able to move the charging port to the outside of the casing? I opened mine up but it looked like it was hard wired, and not on a ribbon cable like the N7 2012.
So I had to cut a hole into the side of the air vent for the charging cable, and it has restricted movement of the passenger side vent.

I'd like to use Tasker, but it seems hard and I don't have the time to devote to learning it.

From the FAQs page of his mobi site it says its possible to get discharge down to 1-2% per day with his ROM though im not sure what settings you need to activate for that - https://timur.mobi/timurs-kernel-n7-2013/faq/

Are you using Torque or DashCommander? Timur's FAQ page says those apps may prevent proper suspend on your tablet which could be the cause of your discharge issues. I think his rom/kernel has stats which tell you what the awake time while in suspend is. If its too high, then some app you're running is most likely waking up too often and discharging your battery. I highly recommend reading his FAQ page.


I bought a UCA202 and the booklet suggests it uses 100mA, but im not using it as i did some testing of the sound quality with the UCA202 compared to the internal DAC in the tablet and it sounds pretty much the same to me. From what I read the 2013 tablets have a better DAC than the 2012 tablets. This allows me to stay unrooted as I dont need the OTG host charging and I dont plan on attaching external storage.

No pics of my install yet as im still waiting for my vents to arrive from Japan. I went with the N7 2013 after reading that you managed to get it to fit between the vents and I do prefer the extra ram, CPU and screen resolution. Looks like i'll need to cut holes on both sides of the vents for the charging cable and the aux cable though.

Tasker is pretty easy to use, its all GUI based and you basically just select options on conditions and actions but since timur's rom already does auto airplane mode, you probably dont need it. The only other thing I use tasker for at the moment is starting and stopping music.

[bigBADbenny]

Quit Torque with Tasker... See post #9
http://forum.xda-developers.com/showthr ... ?t=1927504

Task: Stop Torque
Misc-Send-Intent
Action-org.prowl.torque.REQUEST_TORQUE_QUIT

I adapted this for btSsm as well.

I'll dig it up for the exact syntax used...

[phly]

Quit Torque with Tasker... See post #9
http://forum.xda-developers.com/showthr ... ?t=1927504

Task: Stop Torque
Misc-Send-Intent
Action-org.prowl.torque.REQUEST_TORQUE_QUIT

I adapted this for btSsm as well.

I'll dig it up for the exact syntax used...

Do these commands work only when rooted? I couldnt find any way to get programs to stop. I wonder if this sort of thing works for other programs too cause i'd want to try and get Pandora, Spotify and the music player to quit. At the moment, I can only get them to stop playing but theyre staying alive in the foreground even though they dont seem to drain much battery.

For btssm, I think its been coded well such that it only keeps the process in the background when you hit the home button. Also seems pretty lightweight using minimal RAM.

[bigBADbenny]

Just drop the text into your Tasker backup text and import it.

Sometimes using Tasker quit app just freezes the app so its good to have a deeper approach...

It should show up as a Task that you can use in a Profile.
No idea about rooted or not, I am.

[bigBADbenny]

http://forum.xda-developers.com/showthr ... 77&page=23

Fascinating thread on Nexus power issues, the scope includes:
Cables: plug end body connection for device signalling, 24/25awg cable thickness, cable length...
Auto power on charge script
Slow charge mode solved by removing battery, cleaning contacts...
Max charge power testing results and rebuttal.
Use Ifixit and Instructables websites to review Nexus teardowns...

Another approach: cache partition wipe:
http://www.technobezz.com/fix-nexus-7-s ... ain-issue/

Reseated usb ribbon cable connector (end of page 1, also page 3 is interesting)
http://androidforums.com/threads/nexus- ... ow.751660/

Fix ok google: item #3
http://www.androidauthority.com/nexus-7 ... ms-524510/

So first I'd check the hardware eg seating & cleaning of the internal connectors & tape down the latches, then cache partition reset, then beef up the cables, join the metal ends if required, shorten, use a buck DC converter... Etc...

Once the charge issue is solved, then look at taming vampire apps like google play services, ok google etc. Some can be converted to user apps and hibernated with eg greenify accordingly...

[Monkey]

Just found this removable dash fabrication for the N7 2013: http://www.rtafabrication.com/collectio ... dash-panel

Don't know whether it would work with the Liberty air vents, etc, but great idea!

[no_probbs]

Just finished this project with a Nexus 7 2013, turned out great! Really happy with it.
I ordered an Electric Designs FSL-21 but didn't end up needing it. If anyone is chasing one please PM me?
Located in Melbourne, but happy to post anywhere in Aus.

[Monkey]

Just finished this project with a Nexus 7 2013, turned out great! Really happy with it.
I ordered an Electric Designs FSL-21 but didn't end up needing it. If anyone is chasing one please PM me?
Located in Melbourne, but happy to post anywhere in Aus.

Awesome - pics? I need to put up pics of mine too.
The only issue I had (I think I was the first to do the N7 2013 in a Lib?) is that it doesn't appear you can relocate the charging pins as they are hard wired, not on a ribbon cable like the N7 2012. So having the charger stick out the side interferes with the blades on the airvent. Did you manage to overtime this? I thought about putting a wireless charging pad behind it, but then I'd be compromising sound quality by using BT.

[HyRax]

The only issue I had (I think I was the first to do the N7 2013 in a Lib?) is that it doesn't appear you can relocate the charging pins as they are hard wired, not on a ribbon cable like the N7 2012. So having the charger stick out the side interferes with the blades on the airvent. Did you manage to overtime this? I thought about putting a wireless charging pad behind it, but then I'd be compromising sound quality by using BT.

Simply strip the MicroUSB connector of its sheathing leaving only the plug and cable, and fold over the cable at the wire end, making it as small as possible. You will still need to drill a small access hole into the air vent, but it doesn't have to be big and it won't foul with the air vents either. With mine I put some heat shrink on it to keep everything fixed and tidy. Works a treat.

[Monkey]

Thanks Hyrax!
Have you got any pics? Knowing me I'll probably fk it up - there has been a lot of trial and error (but mainly the latter) with my car projects

[HyRax]

Thanks Hyrax!
Have you got any pics? Knowing me I'll probably fk it up - there has been a lot of trial and error (but mainly the latter) with my car projects

I've been meaning to document it up and add it to my general profile thread, but I've been too busy of late.

I do have a YT video documenting some of my earlier WIP but it doesn't have any shots of the cable. But like I said, there's not much to it.