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Trouble Charging with Docking station

I purchased one of those docking stations with additional battery charger off ebay. However, for some reason the unit isn't charging the device when it's docked. Instead it loses power. I waited almost 2 months for them to finally ship the item now this. I was thinking it may be the 1.5ma adapter that came with it. My test this evening will be to plug up the regular charger in the mini usb port and see if that will charge the unit. Is anyone else having this problem? I was trying to cut expense by purchasing this unit instead of the more expensive ones sold on expansys for a little over $100 usd. I even went as far as implementing a 3.5 mm plug for audio (stereo) and this took quite a few hrs to do. Please give some feedback.

I have the same docking station you have. It charges my phone if I turn the backlight down, and dont run any data programs (gps, wifi or anything like that) If I run much of anything it will drain down. I attributed it to the charger cable that comes with it. Let us know how your tests go. I can voice for the xtra battery spot, it charges my spare in less than an hour from empty.

touchlasvegas said:
I have the same docking station you have. It charges my phone if I turn the backlight down, and dont run any data programs (gps, wifi or anything like that) If I run much of anything it will drain down. I attributed it to the charger cable that comes with it. Let us know how your tests go. I can voice for the xtra battery spot, it charges my spare in less than an hour from empty.
Click to expand...
Click to collapse
Thanks for the reply bud. I said I'll try the OEM charger in the mini port first, and if that works then I'll buy a higher milli amp charger for it (maybe 3 ma). I did a nice little audio mod to it as I discussed and I'll take pictures later when I get in. I really like the unit and the great thing about my audio mod is that it doesn't broadcast my calls over my A/V receiver, it goes directly to my BT headset (conversations stay private), and once I hang up the audio goes back to the A/V receiver, so I can continue listening to my music. The mod only cost me about $3 USD for the necessary parts and some soldering and drilling.

Here are the pics of the mod I did. The Audio works fantastic. I converted the 3.5mm plug to stereo output and well placed too as the device just slide right onto the docking station without any trouble. Now my next task is to find a 3 ma adapter to use as a charger. For some reason even when I use the OEM charger in the mini usb slot the device charges, but does it very slowly as if it was getting the charge from the computer's USB connection, and the 2nd battery slot doesn't charge at all with this method. If anyone would like internal pics (not that they would help much as I've soldered and hot glued all the wires in the device for stability) I will be more than happy to upload some.

charging with cradle
Had the same problem before so I just plug both chargers into the unit. (Athena and cradle adaptor) It now charges abeit slowly with wifi and screen at middle illumination but fast if I turn the screen off( 20% to 100% in 2.5 hrs.). avoid plugging anything else to the usb or any ports while charging. It will grain your battery even if you are not using them.
Can you take a picture of the internal part of the cradle? The part where you installed the audio jack and rca sockets. This is where I am having problems. I find the space too small to install those you installed. Maybe you could give me an idea how to install the same in my cradle.
Another thing, do you think it is possible to put in another USB slot and/or a memory card slot? I'm going to the province(the provincial life here is like 1980's there in the US except for mobile phones and a few computers with limited internet access) and I don't want to carry arround so many gadgets and attachments with me. I have 2 4G usb drives, 16G cf and a 2G mini sd. I keep my file both for business and pleasure outside of my athena for safety. As much as possible, I don't want to attach an external usb hub as it drains my battery. I would rather have an internal hub and changing the led to something smaller to consume less power but integrate them to the cradle.
As much as I want to bring my laptop to the province, the size of my ibm x40 is still to big and heavy for me to carry constantly everywhere.

yetdy said:
Had the same problem before so I just plug both chargers into the unit. (Athena and cradle adaptor) It now charges abeit slowly with wifi and screen at middle illumination but fast if I turn the screen off( 20% to 100% in 2.5 hrs.). avoid plugging anything else to the usb or any ports while charging. It will grain your battery even if you are not using them.
Can you take a picture of the internal part of the cradle? The part where you installed the audio jack and rca sockets. This is where I am having problems. I find the space too small to install those you installed. Maybe you could give me an idea how to install the same in my cradle.
Another thing, do you think it is possible to put in another USB slot and/or a memory card slot? I'm going to the province(the provincial life here is like 1980's there in the US except for mobile phones and a few computers with limited internet access) and I don't want to carry arround so many gadgets and attachments with me. I have 2 4G usb drives, 16G cf and a 2G mini sd. I keep my file both for business and pleasure outside of my athena for safety. As much as possible, I don't want to attach an external usb hub as it drains my battery. I would rather have an internal hub and changing the led to something smaller to consume less power but integrate them to the cradle.
As much as I want to bring my laptop to the province, the size of my ibm x40 is still to big and heavy for me to carry constantly everywhere.
Click to expand...
Click to collapse
I will upload some pics in a bit. I thought about putting in a 2nd USB slot, however now that you've mentioned the internal USB hub, you gave me a new task for tomorrow. I will go to Rat shack and try to find the smallest hub they have and take it apart and somehow get that bad boy to fit into the cradle. If you've researched any that's pretty small post the link and I'll take a look at it. Give me about 30 mins to upload some pics as I have to take the unit apart and stuff. Oh btw I had to strip the 3.5mm down to the bare metal from a cheap headset I had laying around.

The yellow plastic piece is where the stereo adapter is located. I had to shave down a piece of plastic on the insde that was kinda blocking the space. I also made sure that the unit was able to close properly. As you can see in the pictures there's no other wires for the unit to short out on and everything's secured properly with the hot glue, and some soldering.

Is the audio not availble via the usb plug? I was led to belive the usb to 3.5mm headphone adaptors work with the ameo? If this is correct and all the pins have connectors then the audio should be availble without adding a 3rd plug.
The genuine htc cradle does have audio out but looks like it only has 2 plugs so it must be possible?
I have just got a 2nd dock station from ebay to try and make my own 4 in 1 plug for charging, tv out, and hdd connection for the car. Does any one have the mini usb headphone adaptor and the ability to test for continuity between the headphone socket and the usb plug?
regards

delboydell said:
Is the audio not availble via the usb plug? I was led to belive the usb to 3.5mm headphone adaptors work with the ameo? If this is correct and all the pins have connectors then the audio should be availble without adding a 3rd plug.
The genuine htc cradle does have audio out but looks like it only has 2 plugs so it must be possible?
I have just got a 2nd dock station from ebay to try and make my own 4 in 1 plug for charging, tv out, and hdd connection for the car. Does any one have the mini usb headphone adaptor and the ability to test for continuity between the headphone socket and the usb plug?
regards
Click to expand...
Click to collapse
Those 3 in 1 adapters do work, however I did the mod to eleminate the need to carry around any extra hardware. I used the 3 in 1 adapter in the usb slot from T-mobile wing phone and it worked just fine. It has the 3.5mm slot, and 2 mini usb slots. But again I did it this way to eleminate the need for that. I'm currently in the process of finding a small USB hub that I can strip down from it's housing and fit it inside the docking station. I already located a 3ma adapter with variable voltage settings. This should be good enough to run all the components and charge the batteries at the same time. Let me know how your mod goes or if you need some ideas.

I was considering this: http://www.upgradenation.com/Tripp_Lite_The_ultra_small_4-port/U222-004-R/partinfo-id-551698.html USB hub to implement into the docking station. Let me know what you guys think, I will check the size when I get home to see if it will fit. I drew it to scale on a piece of paper just to make sure before I order it. Now keep in mind that I will be taking it out it's housing to get it to fit inside the unit, hence eleminating the extra load. Oh btw problem solved with the charging. Feedbacks please.

tootallk2000 said:
I was considering this: http://www.upgradenation.com/Tripp_Lite_The_ultra_small_4-port/U222-004-R/partinfo-id-551698.html USB hub to implement into the docking station. Let me know what you guys think, I will check the size when I get home to see if it will fit. I drew it to scale on a piece of paper just to make sure before I order it. Now keep in mind that I will be taking it out it's housing to get it to fit inside the unit, hence eleminating the extra load. Oh btw problem solved with the charging. Feedbacks please.
Click to expand...
Click to collapse
Got a USB hub that may work. It's a hybrid. I also attached pics of how I modified my cradle.

yetdy said:
Got a USB hub that may work. It's a hybrid. I also attached pics of how I modified my cradle.
Click to expand...
Click to collapse
I got in late yesterday, and wasn't able to check the size against the cradle. I see you have slots for a flash card reader on yours, the question now is, have you found a spot to fit all that in there? The size of the one I saw looks like it would work, but it doesn't have the card readers in it. I think that would be very ideal to have in there too. Let me see pics of the final product, if you can get it to fit, if you can't no biggy i'll just do without the card reader in it.

tootallk2000 said:
I was considering this: http://www.upgradenation.com/Tripp_Lite_The_ultra_small_4-port/U222-004-R/partinfo-id-551698.html USB hub to implement into the docking station. Let me know what you guys think, I will check the size when I get home to see if it will fit. I drew it to scale on a piece of paper just to make sure before I order it. Now keep in mind that I will be taking it out it's housing to get it to fit inside the unit, hence eleminating the extra load. Oh btw problem solved with the charging. Feedbacks please.
Click to expand...
Click to collapse
What was the solution for charging? Have you talked with the folks at gpsforless or HTC to see if they could fix there design, by using the designs that you have developed so far? Or are you interested in making a couple extra docking stations for a fee? Sometimes we have more time than money and other times we are starved for time... Lately, I have been starved of time...
Thanks for taking the time to develop a solution that I have been dreaming about, while on the road traveling, ect...
Part of the work around that I was using was BT audio recievers, they have been a great work around, but also have some limitations as well...
I look forward to hearing and seeing good things from you in the future
v/r
Bob

yetdy said:
Got a USB hub that may work. It's a hybrid. I also attached pics of how I modified my cradle.
Click to expand...
Click to collapse
Have you gotten any of the hubs to allow for you to power and recharge the device or spare battery via USB?

the usb hub works but it literally drains my battery so much that i prefer not to use it anymore.

[Q] Modify car cradle to automatically enable car mode ?

Hi there,
I just bought an active car cradle for the Htc HD2 (Carcomm), no problem, working as expected.
Then I began wondering why the phone would not go into car mode when connected to the car cradle... If it's a car cradle, it should put the phone into car mode, right ??
So I was wondering what could possibly trigger the phone into car mode when connected to a charger.
Found this in another thread (http://forum.xda-developers.com/showthread.php?t=767961):
To the person who wanted to know about connecting pins 2&3 to 4 to create a car doc? Looking at the USB spec datasheet It's not that simple. You need to insert a voltage divider across the data lines and tie it back into the 3.2v of the device. A little more trouble than it's worth unless you are doing it for the learning experience.
Click to expand...
Click to collapse
and also from user dabigcheezze :
unfortunately it is a problem with froyo, whenever the phone is placed into dock mode, no matter what the charging input, it will only show up charging in usb mode, i have a homemade dock cable with pin 4 to ground, when i hook that up to my 1 amp charger it only shows usb, using a normal cable it shows ac charging, it has nothing to do with the HTC dock, it will happen whenever the phone is placed into dock mode, it also locks the vol output on the 3.5 jack 3/4 up....sooooo stupid.
Click to expand...
Click to collapse
Does anyone know about grounding pin 4 to enable car mode ? what about power, is the charger powering enough the phone while using BT, GPS and navigation ? Also, the limitations in Froyo are they gone in Gingerbread or could it be fixed ?
Thank you for sharing your experience, I would really like to have a car cradle working 100%

Nobody ?
Sent from my HD2 using XDA App

Come on, I'm sure somebody did the modification... or tried to do it
Willing to share ?

Hi !
Just wait I can contact the guy I wish to buy that second hand HD2 first, then find an appropriate car charger craddle, and I'll look for a solution.

Don't know how to automatically enable car mode, but just solder the 2 middle wires in your USB cable together and you'll get 1A instead of 500mA, which charges way faster. Your car charger needs an output of 1A, of course, else it's just gonna remain 500mA.

StephanV said:
Don't know how to automatically enable car mode, but just solder the 2 middle wires in your USB cable together and you'll get 1A instead of 500mA, which charges way faster. Your car charger needs an output of 1A, of course, else it's just gonna remain 500mA.
Click to expand...
Click to collapse
Thanks for your reply. Yes, it's true. I've seen this small hack to enable AC charging for cheap chargers that are charging with USB mode (400mA I think).
My charger was good enough to provide AC charging (1A), which is great, but not enough to enable the car mode...
What I would like to confirm is if grounding pin 4 will really put the phone in car mode when plugged into the car cradle, before doing it myself...

Do not hack the hardware!
Use a software
http://forum.xda-developers.com/showthread.php?p=8178010

Thank you for your response.
But... is it a software for windows only ?
I run Android on my HD2

Unfortunately, the software only runs on Windows Mobile :-(
So you have to try that:
http://translate.google.at/translat....cz/forum/viewtopic.php?f=3&t=73&p=1037#p1037
seen here:
http://www.youtube.com/watch?v=Nx0zPFQtyxs
I personally ordered the original car holder from htc and it is really a very good one!

Excellent !!
I think that if the mentionned modification works with a HD2 AND a Desire HD, the official Htc android software should work also, like the windows software in the video.
Thank you, it's great ! I will post here my results when done

Even easier - try using PhoneWeaver (can't add a link as a noob)
It's basically an app for setting your phone's parameters, based on all sorts of external influences, such as time, date, power source etc.
So, for example, I have the following settings:-
6:15 am - turn phone on, set volume to Normal
8:15am - set volume to low (for when I'm in the office - its a personal mobile)
4:45pm - set volume to Normal
6:45pm, turn wireless on (as I'm at home, and browsing is much faster)
10:00pm - turn phone / wireless off, set volume to low, start SPB Time (my alarm clock)
Additionally, I have the following:-
If external power is detected AND Activesync isn't running (ie it's not connected to a PC) then turn on Bluetooth and increase volume (this is because the only other possibility for this environment is when its in the powered car cradle)
If external power is detected AND Activesync IS running, turn Bluetooth off, but turn wireless on
It's completely brilliant - never fails and I never have to remember to do anything

Nexus 7 in-dash install in European Toyota Avensis T25 (2008)

Hello,
I share in this thread, my experience of mounting a 2012 Nexus 7 in my 2008 Toyota avensis.
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The biggest problem was about :
- Power : a Nexus 7 tablet will not boot, or behave strangely if battery is over discharged. This is a real problem because you have to take care of battery deep-sleep when not in car, remove battery heater apps that will prevent to sleep (frequent with GPS apps). To resume, having a battery in the Nexus 7 in car install raise a lot of complication.
- Risk and security to have an Li-ion battery in the top of my dashboard (danger with high temp and direct sun exposition) : Even in north of France, direct sunlight can raise very very high temperature at the top of the dash. So i was very worried to have a lithium battery. For my safety. I was afraid to find my car burned. It can arrive. I think it's really not a good thing when i see other in-dash mount that keep battery inside the nexus.
So, i decided to remove completely the Li-Ion Battery, and power the tablet directly from a 12V->3.7V DC converter, connected to my cigarette lighter.
Everythink work perfectly now. The only two small side-effect are :
- Car ignition will shut off power 2 ou 3 second, and tablet will reboot.
- 40 seconds boot time. It could be long, but i am rarely in my car for less than 2 minutes. So it's really not a problem. My Tom Tom GPS sometime take 30 seconds to be ok.
Total cost for this project are
- 15 dollar for 12V->3.7V converter on ebay
- 130 dollar for a 16G Nexus 7 on ebay
- 120 dollar for a genuine toyota navigation dash mount extracted from an broken avensis that had toyota GPS.
- Some dollar for adhesive, cigarette lighter plug, etc...
Here is some photo. I will add photo from inside if someone is interested (maybe not for a Toyota).
The main interest is to share for my Power problems
(sorry for my french-english)
My avensis before nexus 7 install
ebay - 12V to 3.7V DC Converter
ebay - Genuine Toyota GPS dash part
Final mount

Battery Wires
Which battery wires did you connect the DC-DC converter to? I see the connector has 2 red and 2 black wires.
Thanks

That is amazing. It turned out very professional looking and clean. May I ask how long it took you to get everything just right? i.e. months, weeks, ect. Very very impressive work.

this is really cool
Sent from my HTC One using Tapatalk

edwin108 said:
Which battery wires did you connect the DC-DC converter to? I see the connector has 2 red and 2 black wires.
Thanks
Click to expand...
Click to collapse
On the Nexus 7 :
- I cut the small battery connector keeping the longest cable possible (so i have say bye bye to the battery !)
- I have connected
> the 2 red cable of the nexus 7 connector to the red DC-DC output
> the 2 black cable of the nexus 7 connector the the yellow DC-DC output
> I cut the yellow and white (the 2 remaining) cables of the nexus 7 connector. Those 2 cable role is to let the nexus 7 know about the temperature and battery status. Not anymore useful as no more battery.
---------- Post added at 09:21 PM ---------- Previous post was at 09:17 PM ----------
nicholi2789 said:
That is amazing. It turned out very professional looking and clean. May I ask how long it took you to get everything just right? i.e. months, weeks, ect. Very very impressive work.
Click to expand...
Click to collapse
Thanks. After 3 month, everything work perfectly. It took me about 1 month before i was able to find the best balance.
I unmount Toyota dashboard about 4 times (bad wire, with battery / without battery, etc...)
I really stressed the Nexus 7 and i can say it's really robust !
I am not worried anymore of battery explosion. I wait 45 seconds before tablet is ready to work.

Nice install! I'm going this route with mine.
Are you using Timur's Rom/Kernel?
How did you set it up to power on with the car without having access to the power button on the N7?
Thanks!

I wonder if I can do something like that on my car... And how to make it pleasing.
Sent from my Nexus 7 using Tapatalk

looks great very well done

@iiolivier Wow man - that's awesome. I have toyota avensis 2003 with GPS included. And I already have Nexus 7 2012.
I will definitely try this.
Can you provide any link for this dc adapter, please? I'm not well-known with electric, wires and etc. (maybe PM to me will be great). Thanks in advance!!!
Cheers from Bulgaria!

iiolivier said:
B]Risk and security to have an Li-ion battery in the top of my dashboard[/B] (danger with high temp and direct sun exposition) : Even in north of France, direct sunlight can raise very very high temperature at the top of the dash. So i was very worried to have a lithium battery. For my safety. I was afraid to find my car burned. It can arrive. I think it's really not a good thing when i see other in-dash mount that keep battery inside the nexus.
So, i decided to remove completely the Li-Ion Battery, and power the tablet directly from a 12V->3.7V DC converter, connected to my cigarette lighter.
Click to expand...
Click to collapse
I've had my Nexus 7 installed in my truck last year, but am concerned because I live in Arizona and it's starting to get hot. So there are no issues removingthe bbattery and running the Nexus 7 directly off power? What if I'm currently plugged in from microusb port of tablet to a cigarette lighter charger? this is all hidden behind the dash. Will it still receive power this way?
Bawb3 said:
Nice install! I'm going this route with mine.
Are you using Timur's Rom/Kernel?
How did you set it up to power on with the car without having access to the power button on the N7?
Thanks!
Click to expand...
Click to collapse
I'll try to find it as I did this mod last year and didn't save the url. There is a bootloader adb mod where you can set the Nexus 7 to boot by itself when it receives AC power. I have it set up to boot when key turns ignition and power off after 1 minute without power, using Tasker.
Edit, here's the adb command to have the tablet power on when it receives AC power
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.
Click to expand...
Click to collapse

you could connect your 3.7v adapter to a constant 12v line and then connect your usb OTG power adapter to a switched 12v line. Then use tasker to detect when the 12v switched goes dead and 'hibernate' the tablet. Then the tablet would run in low power mode off of the car battery untill you turn the car back on. No waiting for the tablet to boot that way and you would keep your time/date.
Great idea about the 3.7v adapter though. I'm stealing that one so I don't need a LiIon battery in the tablet at all.
-J

miatawnt2b said:
you could connect your 3.7v adapter to a constant 12v line and then connect your usb OTG power adapter to a switched 12v line. Then use tasker to detect when the 12v switched goes dead and 'hibernate' the tablet. Then the tablet would run in low power mode off of the car battery untill you turn the car back on. No waiting for the tablet to boot that way and you would keep your time/date.
Great idea about the 3.7v adapter though. I'm stealing that one so I don't need a LiIon battery in the tablet at all.
-J
Click to expand...
Click to collapse
Were you replyingto me? II'm not well versed in electrical tinkering. What would I have to do to take the battery out of my tablet, if you don't mind explaining. Currently the tablet is receiving power through a cigarette lighter adapter hard wired behind the dash. When it receives power it boots the tablet, when power is off Tasker shuts down the tablet after 1 min. I'd like to take the battery out because of extreme temperatures here.

Can you tell me how did you install the nexus 7 inside the toyota navigation dash mount ? It's not to biger ? Do you have any pictures from inside the unit with the system mounted where I cand see how you mounted (fixed) the tablet inside? I wont to do the same thing, but my problem is that Nexus 7 (2012) has this dimensions: 198.5 x 120 and do not fit inside. The inside dimensions are maximum 180 x 110. Please help with some pictures. Thanks.

movy said:
Can you tell me how did you install the nexus 7 inside the toyota navigation dash mount ? It's not to biger ? Do you have any pictures from inside the unit with the system mounted where I cand see how you mounted (fixed) the tablet inside? I wont to do the same thing, but my problem is that Nexus 7 (2012) has this dimensions: 198.5 x 120 and do not fit inside. The inside dimensions are maximum 180 x 110. Please help with some pictures. Thanks.
Click to expand...
Click to collapse
I'm in the process of upgrading from the 2012 N7 (which I just sold) to the 2013. I wanted to fill in the gaps on either side of the tablet in the dash because it was bothering me. Here's what I did.
I dremeled the sides of my dash and a bit behind it to accommodate the tablet. You may need to do a little dremeling/sanding to accommodate yours. I then built a 3 sided wooden box that serves as a double DIN dummy to mount the N7 too. The dimensions are:
Front face: 7"
Sides: 5 1/2"
Top and bottom: 5 1/2"
As you can see in the pictures, I cut out a portion of the sides and bottom so it could wrap around the single DIN radio that's behind the N7 in the dash. The box wouldn't have fit for me otherwise, but for you, at least leave the back open so you can put cables and stuff inside.
I left the side mounts that the old radio bolted to in the truck, so basically the box slides in and is held in place just by the pressure from the sides of the mounts and the front when the dash is put back on.
On the wooden box I put two strips of double sided sticky tape. I chose the heavy duty 5lbs, but it's a little more than what's needed and makes adjusting a pain. Just use the cheaper 2 lb strength tape.
On the front of the box, attached to the sticky tape, I mounted a hard plastic snap on case/shell for the tablet (only thing not pictured). The tablet snaps into the case and is subsequently held on the box. You can just take the tablet out of the case if you need to remove it. That way, you're not affixing the actual tablet to the box.
Finally, I had spaces on either side of the tablet (the dash was a bit wider than the tablet itself). I lived with it for a year, but it was ugly and I finally decided to do something about it. I bought standard double DIN trim for a radio, dremeled, sanded, and cut it so it fits, and taped it to the sides of the tablet (pictured). Now, there won't be any spaces, and it looks like it's actually a factory install.
Hope this helps.

I want to know how he mount Nexus 7 in Avensis T25 dash navigation. This is a picture of 2 way to install: the whole tablet (in first case) or only the lcd touch screen in original frame of navigation. For example this is how it fit a GPS Lexand (Russian) inside the unit. The dimensions of the gps-tablet in this case are max 180*110 mm to fit in. And olso, the dimension of lcd (of image) are max 155*90 mm to fit in (la lcd of 7") . This is my problem in finding a tablet with this exterior size and with this lcd size.

Hy guys,
today I also tried to remove my Nexus battery to power it directly. Sadly it isn't working!
The screen is flickering one time, after I hit the power button. Does someone know what could be the issue?

Mugga said:
Hy guys,
today I also tried to remove my Nexus battery to power it directly. Sadly it isn't working!
The screen is flickering one time, after I hit the power button. Does someone know what could be the issue?
Click to expand...
Click to collapse
can you take a pic of how you hooked it up?
50,000 foot howto:
You will need a 12v to 3.7v converter. take the + and - 3.7v wires and attach them to the red/black wires of the battery plug. If you don't want to cut the plug off the battery you can solder directly to the board where the connector is attached. There are an additional two wires off of the battery plug I believe they are white/yellow. I think these are temp sensors. You should be able to leave them unattached, but I haven't played with it yet. You may need to bridge them with a small resistor.
-J

miatawnt2b said:
can you take a pic of how you hooked it up?
50,000 foot howto:
You will need a 12v to 3.7v converter. take the + and - 3.7v wires and attach them to the red/black wires of the battery plug. If you don't want to cut the plug off the battery you can solder directly to the board where the connector is attached. There are an additional two wires off of the battery plug I believe they are white/yellow. I think these are temp sensors. You should be able to leave them unattached, but I haven't played with it yet. You may need to bridge them with a small resistor.
-J
Click to expand...
Click to collapse
Haven't got any pics, but i hooked them up directly without the battery. The two red lines with the plus line, and the black ones with ground.
I tried it with my car dc-dc converter. I can program the voltage down to 4,2V. I also measured the voltage directly at the nexus pcb, and it says 4,15-4,2V. I tried it with different voltage levels, up to 5v. When the voltage is too low, I just get one flickering. With a little bit more, I get something like a grey screen. And with round about 5v, I get the Nexus startup screen for about 2 seconds, and then the screen is going black, but the backlight is still turned on.
When I attach the battery like before without any external power, everything is running smooth. I don't really see what could be the problem. The dc-dc converter is able to provide 10A.
EDIT:
Nevermind got it working!
The problem was that the wires for the testing at home where to thin, to provide enough juice (Ampere). After going with two cables for each line, the tablet was booting fine. Any way thx for the help.

iiolivier said:
- Car ignition will shut off power 2 ou 3 second, and tablet will reboot.
- 40 seconds boot time. It could be long, but i am rarely in my car for less than 2 minutes. So it's really not a problem. My Tom Tom GPS sometime take 30 seconds to be ok.
Click to expand...
Click to collapse
Hi. Great post, thank you! I plan to do the same but had a few questions:
1. How is it faring over long term use? I imagine the 12V from a car battery is pretty 'noisy' so my concern is with device longevity.
2. Does the N7 2013 model work with 3.7V as well, or does it need a different voltage?
3. Are you able to hook up USB devices using an OTG cable without the battery?
My ideal solution would be to hook the N7 battery connectors to an 'always on' power line and the micro-USB connectors to a switched power line. This way I can use Tasker to hibernate/shut-down the N7 when the car is turned off. A trickle charge after hibernation/shutdown probably won't drain out my car battery too soon. I'm not so much concerned about start-up time (though a quicker startup through hibernation would be a bonus), but rather the concern that repeatedly shutting off power to the tablet abruptly (without giving it a chance to shutdown) probably wouldn't be good for it.
Obviously the assumption here is that the N7 uses voltage detection at the micro-usb connection to determine if power is incoming to the battery. I'll need to test this out. But I want to know if OTG even works (I need it for backup cam) before I tear down my N7 and start poking around with a multimeter.

question
Hi guys. After few long weeks I finally managed to put my nexus 7 in.
Everything works pretty much ok but I was a bit worried about the battery so I bought a power supply buck module, which proved to be a beast . Provides my continuous 3.7V, having the battery removed without any problem AT ALL.
I would like to know if someone tried something similar because I am a bit concerned about the power consumption. Is it ok to leave it on all the time, or not ? Please advice.

Few general questions..

Questions:
- I copied over a few mp3's. In the HTC music app I see there is a way to turn off getting album art, etc. Anyway, out of 10 songs, 3 of them got tagged with correct album art, correct band. The rest show up in an unknown folder. Any way to stop or fix it? Now that I turned off album art, should I delete the songs and put them back again?
- I have a 1,5A car charger. Do you think it's safe to use mp3 and GPS for an 8 hour drive or do you think I'm best to stick with just GPS? I'm not using bluetooth as I only have 3.5mm jack in my car.

yuppicide said:
Questions:
- I copied over a few mp3's. In the HTC music app I see there is a way to turn off getting album art, etc. Anyway, out of 10 songs, 3 of them got tagged with correct album art, correct band. The rest show up in an unknown folder. Any way to stop or fix it? Now that I turned off album art, should I delete the songs and put them back again?
- I have a 1,5A car charger. Do you think it's safe to use mp3 and GPS for an 8 hour drive or do you think I'm best to stick with just GPS? I'm not using bluetooth as I only have 3.5mm jack in my car.
Click to expand...
Click to collapse
1 - id force stop the music app and clear all data from it and when you reopen it turn off album art and see if you get no album art anyways, it could be that your mp3 have meta data that contain the album art.
2 - i see no problem with this..are you concerned about heat? or it drawing too much power? I've never had an issue doing both of the above mentioned things and using a charger, go for it. Ive driven from NY to TX using gps and audio through my car through 3.5 and never had any issues with any phones i had.

Thanks. Will try your music suggestion soon as I get home.
As for the power question, I had an HTC EVO and the GPS used to draw more power than the charger provided. Granted its been years since I've really used a car charger because most of my drives have been short. Not to mention this runs newer Android.
Today I left work, my phone was 100%. I drove for an hour using GPS, took 5 or 6 pictures, used GPS for another hour, here I am about 5 minutes from home am at 24%.
In my OP I said wrong.. I don't have a charger yet. Will have to see if radio shack has a 1.5a in stock. Most places only carry 1a.
deakelem said:
1 - id force stop the music app and clear all data from it and when you reopen it turn off album art and see if you get no album art anyways, it could be that your mp3 have meta data that contain the album art.
2 - i see no problem with this..are you concerned about heat? or it drawing too much power? I've never had an issue doing both of the above mentioned things and using a charger, go for it. Ive driven from NY to TX using gps and audio through my car through 3.5 and never had any issues with any phones i had.
Click to expand...
Click to collapse

yuppicide said:
Thanks. Will try your music suggestion soon as I get home.
As for the power question, I had an HTC EVO and the GPS used to draw more power than the charger provided. Granted its been years since I've really used a car charger because most of my drives have been short. Not to mention this runs newer Android.
Today I left work, my phone was 100%. I drove for an hour using GPS, took 5 or 6 pictures, used GPS for another hour, here I am about 5 minutes from home am at 24%.
In my OP I said wrong.. I don't have a charger yet. Will have to see if radio shack has a 1.5a in stock. Most places only carry 1a.
Click to expand...
Click to collapse
Go to target they have dual USB car chargers that work great! They are about $15-20 but the brand is Griffen and they work very well and will be more than enough to keep your phone charged and at the very least... Keep it from discharging they are in a sorta basic red and white or range and white thin box in their electronic depr
---------- Post added at 07:15 PM ---------- Previous post was at 07:11 PM ----------
deakelem said:
Go to target they have dual USB car chargers that work great! They are about $15-20 but the brand is Griffen and they work very well and will be more than enough to keep your phone charged and at the very least... Keep it from discharging they are in a sorta basic red and white or range and white thin box in their electronic depr
Click to expand...
Click to collapse
They look like this! And believe they are 2 amps

deakelem said:
Go to target they have dual USB car chargers that work great! They are about $15-20 but the brand is Griffen and they work very well and will be more than enough to keep your phone charged and at the very least... Keep it from discharging they are in a sorta basic red and white or range and white thin box in their electronic depr
---------- Post added at 07:15 PM ---------- Previous post was at 07:11 PM ----------
They look like this! And believe they are 2 amps
Click to expand...
Click to collapse
Ugh..trouble adding pic

Problem is those chargers usually put out 2A or more. People here reported overheating, screen problems, and bricking their phones when used with a charger of higher amp. Also might be due to some crappy Chinese brand. Who knows.

1 - I managed to get a 1.5a car charger online for under $5 with shipping.
2 - I can't figure out the damn music thing. I just copied over a bunch of songs.. all of them are displaying a picture of the Bee Gee's lol! The songs are hardcore music.. not even close to the same genre. Driving me crazy.

yuppicide said:
2 - I can't figure out the damn music thing. I just copied over a bunch of songs.. all of them are displaying a picture of the Bee Gee's lol! The songs are hardcore music.. not even close to the same genre. Driving me crazy.
Click to expand...
Click to collapse
Test your music.problem on a different music app or an (shudder) Apple. See what happens.
Send me your Bee Gees songs. Problem solved. lol

Download this and you can edit your mp3s so they will catalog correctly.
https://play.google.com/store/apps/details?id=com.ADnet

[Discussion/Tips] Nexus 7 as Car-Tablet.

There's millions of these devices around. If not laying in a draw or closet, they're on craigslist or ebay half of a N7'13, (2013 model should be considered if purchasing).
Share and discuss your setup, apps, and experiences here.
ROMs:
Timur's USBRom: Android 4.2 Jellybean. No longer developed.
http://www.adrive.com/public/hMdX4p/cm-10.1-20130817-USBROM-grouper.zip
Gapps: http://www.adrive.com/public/rj748P/gapps-jb-20130812-signed.zip
AutoDroid: Android 4.4.4 Kit Kat. No longer developed.
http://forum.xda-developers.com/showthread.php?t=2789993
*May have a problem booting after install. Flash a below kernel to fix.
Kernels:
Kangeroo: For Kit Kat ROMs. Inactive(?) since Jan 2014.
http://forum.xda-developers.com/showthread.php?t=2558717
Oxydo: For Lollipop ROMs.
http://forum.xda-developers.com/nexus-7/development/oxydo-revamped-kernel-nexus-7-2012-t2978950
Apps:
Headunit: Android Auto head unit app.
http://forum.xda-developers.com/gen...nit-android-auto-t3125252/page69#post62485618
Power Event Manager 1.8: Changes power settings for above kernels allowing tablet to sleep/wake with external power.
http://forum.xda-developers.com/showpost.php?p=62287264&postcount=145
App Ops: Or any permission manager you like.
https://play.google.com/store/apps/details?id=com.findsdk.apppermission
Autosleeper Auto power ON-OFF: I haven't tried this but functionality seems somewhat equivalent to PEM above.
https://play.google.com/store/apps/details?id=com.as.powerchecker
Wakelock Detector [Root]: Use with App Ops to stop apps keeping the tablet awake.
https://play.google.com/store/apps/details?id=com.uzumapps.wakelockdetector&hl=en
Trigger: Tasker-like app for automation. Simple set-up..
https://play.google.com/store/apps/details?id=com.jwsoft.nfcactionlauncher
Tasker: Powerful automation app but incredibly user unfriendly.
https://play.google.com/store/apps/details?id=net.dinglisch.android.taskerm
[*]Secure Settings: Allows Tasker to perform even more powerful automation.
https://play.google.com/store/apps/details?id=com.intangibleobject.securesettings.plugin
[*]Power Event Manager Helper: Helps PEM kill a few stubborn apps then put the tablet in lp0.
Attached in 2nd post.
Hardware:
OTG Cable: Don't cheap out here, charging for the tablet and phone must go through the wires.
http://www.amazon.com/dp/B00UJ5D5ZS?psc=1
http://www.amazon.com/gp/product/B00NSBVNCM?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00
Ground Loop Isolator: Filters alternator, and charging whine. Doesn't degrade music quality.
http://www.amazon.com/gp/product/B00NSBVNCM?psc=1&redirect=true&ref_=oh_aui_detailpage_o00_s00
Digital Audio Convertor: Can be found locally at music stores. Fantastically excellent sound!!
http://www.behringer.com/EN/Products/UCA202.aspx
Others/Tips/etc:
Put the tablet in bootloader and type this command into CMD/terminal.
This makes the tablet to boot when external power is turned on without physically pressing the button, even if the battery has completely discharged.
Code:
fastboot oem off-mode-charge 0
If using a Lollipop ROM and experiencing the NlpCollectorWakeLock here's a fix, you must be rooted:
Remove com.google.android.gms with titanium backup (or another utility),
Download the latest "230" version of Google Play Services from apkmirror.com,
Install,
Reboot.
Smooth Scroll Mod: Possible created a random reboot on the order of once 3 or 4 days.
It goes without saying, maybe, but do not install 3rd party widgets. Beautiful Widgets for example will cause thousnads of different wakelocks though a night. -inadvertently tested.

Attached is my V2 blocked list for Debloater. It removes more apps, but leaves a few others for better stability.
V2 now removes Connectivity Services and Play Services. I recommend using on a clean install immediately going into airplane mode so no apps will start auto-updating.
With Play Services being removed by the app you will need to install with adb if no file manager is installed beforehand.
Created a Tasker app that helps Power Event Manager. Secure Settings and Power Event Manger is needed.
If PEM doesn't shut down in 7 seconds, The app closes some problem apps, hope you used the debloat list, and calls PEM to sleep the tablet. Upon wake up app then disables airplane mode.

My current setup [Edited 09/18]:
Stock lollipop, from factory image, rooted, with Oxydo-Revamp kernel.
All apps not suitable for stand-alone tablet use have been removed. Debloat list is above in post #2.
Power Event Manager installed as system app.
Es File Explorer for file management, and ftp file transfer.
$3.50 OTG cable from Amazon. Charging seems severely hampered. Tablet and phone both occasionally discharge.
OTG is now handled by the 2nd cable listed in the OP with Amazon Basic USB extensions. Charging problems fixed.
Cheap USB 2.0 hub with independent power. Simple and impressive mod.
Torque Pro with a ELM327.
Tasker. To kill apps and use Power Event Manager to put the tablet to sleep.
Now using my Power Event Manager Helper app.
Behringer UCA202 to stock stereo AUX input: This is an incredible mod. Highly recommend over bluetooth.
Notes:
Torque can keep the phone awake if configured improperly.
Leaving ES File Explorer in FTP mode will also cause a partial wakelock.
Google Play Services, and Google App are causing wakeup triggers every 2-3 minutes.
Power Event Manager combined with Oxydo kernel is putting the tablet to sleep reliably.
Power Event Manager isn't terribly reliable. The Tasker profile is set to kill apps and call PEM for when PEM alone fails.
My awake time with stripped system and Tasker is consistently 0% over 24 hours. Longer periods show Tasker awake for 2s!
Settings:
I use Synapse and UKM TricksterMod for kernel management. Since battery life isn't a primary concern, my settings are to maximize the tablet's performance.
Turning the Nexus7 into a "terminal" is about the only hope it has to run Lollipop.
Tablet can run music, maps, and youtube flawlessly. Chrome appears to be the biggest problem app.
CPU Minimum frequency is set a 640MHZ 340MHZ,
Maximum 1624MHZ 1500MHZ,
Ondemand Governor.
Splitting the power to use two chargers is super simple when you figure it out.
Open the hub,
Remove the red wire from the PCB, and tape it off.
Connect a salvaged USB cable's red wire to the where the previous was,
Connect the new black wire to the PCB with the existing black wire.
Green and white wires on new cable are not used.

Whoa, mine if using stock lollipop is barely usable (too slow especially when multitask). Then I installed tiimut'r usbrom it's a lot bettrr (but then I needed the inmersive mode).
Current setup is slimrom (slimkat 4.4.4), all converted to all-f2fs. I dont need usb host stuff (yet), so far i'm satisfied with it. Use macrodroid for auto on/off stuff, automate as launcher, google maps for navigation, spotify/poweramp for music, and dash command for obd2 stuff.
Sent from my LG-D802 using Tapatalk

tesna said:
Whoa, mine if using stock lollipop is barely usable (too slow especially when multitask). Then I installed tiimut'r usbrom it's a lot bettrr (but then I needed the inmersive mode).
Current setup is slimrom (slimkat 4.4.4), all converted to all-f2fs. I dont need usb host stuff (yet), so far i'm satisfied with it. Use macrodroid for auto on/off stuff, automate as launcher, google maps for navigation, spotify/poweramp for music, and dash command for obd2 stuff.
Sent from my LG-D802 using Tapatalk
Click to expand...
Click to collapse
I ran into the multitasking bit while setting up , everything last night.
With Torque and Headunit, running as it would in the car it's perfectly usable.
Open chrome, settings, es file explorer, and Ampere and it falls apart. Chrome is the biggest problem though.
How does Dash Command run for you? I've tried it, and seen many, that say the refresh rate is slow.

fr4nk1yn said:
I ran into the multitasking bit while setting up , everything last night.
With Torque and Headunit, running as it would in the car it's perfectly usable.
Open chrome, settings, es file explorer, and Ampere and it falls apart. Chrome is the biggest problem though.
How does Dash Command run for you? I've tried it, and seen many, that say the refresh rate is slow.
Click to expand...
Click to collapse
I had issues even opening up Google maps while in lollipop, soooo sllooooow. I only able to open maps, or music, or OBD stuff, cannot run them together. Now on kitkat I can run at least 2 apps simultaneously without any issues (like maps and music, or music and OBDII stuff). I did get issues when running three apps (music, maps, and obdII stuff). As for dashcommand, the refresh rates is quite ok for me. I like dashcommand morecompared to torque since it has nicer layout/themes out of the box. It's like having GTR multi information display that looks very factory.
I have another irritating issues though. If the nexus7 battery nearly full (above 90%) and charging. I hear a lot of strange noises, even when the engine is off. I touch the screen, doing any activities creates a lot of noises. if I disconnect the charger the noises are gone! and if the battery was like at 50% and charging no funny noises either. I was wondering how do I fix this.....
My setup is using the aux output of the nexus 7 to aux input of the factory bose head unit. Tried to use bluetooth to aux adapter but I did not like the sound quality (too many hissing noise) and also introduces alternator whine
Should I get the USB DAC thing?

tesna said:
I had issues even opening up Google maps while in lollipop, soooo sllooooow. I only able to open maps, or music, or OBD stuff, cannot run them together. Now on kitkat I can run at least 2 apps simultaneously without any issues (like maps and music, or music and OBDII stuff). I did get issues when running three apps (music, maps, and obdII stuff). As for dashcommand, the refresh rates is quite ok for me. I like dashcommand morecompared to torque since it has nicer layout/themes out of the box. It's like having GTR multi information display that looks very factory.
I have another irritating issues though. If the nexus7 battery nearly full (above 90%) and charging. I hear a lot of strange noises, even when the engine is off. I touch the screen, doing any activities creates a lot of noises. if I disconnect the charger the noises are gone! and if the battery was like at 50% and charging no funny noises either. I was wondering how do I fix this.....
My setup is using the aux output of the nexus 7 to aux input of the factory bose head unit. Tried to use bluetooth to aux adapter but I did not like the sound quality (too many hissing noise) and also introduces alternator whine
Should I get the USB DAC thing?
Click to expand...
Click to collapse
I'm sure lollipop is working so well because of everything I stripped out of it. I'm about to strip some more. Was working on gauges for torque. I'll give Dash Command another try though. It does look much better.
I'm still getting my cables added to my cart but you need one of these for noise:
http://www.amazon.com/PAC-SNI-1-3-5...=1440642269&sr=8-1&keywords=3.5mm+ground+loop

Are you using a stripped down stock ROM or you manually disabled everything?

fr4nk1yn said:
I'm sure lollipop is working so well because of everything I stripped out of it. I'm about to strip some more. Was working on gauges for torque. I'll give Dash Command another try though. It does look much better.
I'm still getting my cables added to my cart but you need one of these for noise:
http://www.amazon.com/PAC-SNI-1-3-5...=1440642269&sr=8-1&keywords=3.5mm+ground+loop
Click to expand...
Click to collapse
I just bought one of these.. (not exactly that brand), on mine one of the channels is not working so I only got one side audio channel only It also degrades the sound quality I think. I guess I need to bought the better one.
EDIT: What if I buy the ground loop isolator intended for 12volt line like this one? Install it on 12v cigarette lighter (before 12v to 5v dc-dc adapter). If this one works the audio quality will not changed as the ground is lifted on the 12v line.

gabrielbsb said:
Are you using a stripped down stock ROM or you manually disabled everything?
Click to expand...
Click to collapse
Yes, A manually stripped/blocked stock ROM.
tesna said:
I just bought one of these.. (not exactly that brand), on mine one of the channels is not working so I only got one side audio channel only It also degrades the sound quality I think. I guess I need to bought the better one.
Click to expand...
Click to collapse
Hopefully the one I ordered works. It has a decibal increase to make up for that degradation from the transformers.

fr4nk1yn said:
Hopefully the one I ordered works. It has a decibal increase to make up for that degradation from the transformers.
Click to expand...
Click to collapse
I ended up ordering one of these . Let's see how it goes few days from now when the package arrives (and time to install it)

Counting on PEM to sleep the tablet might not be the best idea. It only seems to actually do it IF the tablet is charging in OTG mode.
Tablet went dead in the car during a test possibly because the OTG cable, or another cable, is malfunctioning.
Might have to go Tasker although I've never gotten it to work properly for anything, and I've never accepted it won't demolish battery polling every few seconds.

Damn. Whatever happened to my tablet it appears to be dead. Won't power on, won't reboot. May be a short lived experiment.
I've ordered hundred of dollars worth of parts for the car so If it doesn't charge by Wednesday i'll have to buy a N7'13 off CL.

fr4nk1yn said:
Counting on PEM to sleep the tablet might not be the best idea. It only seems to actually do it IF the tablet is charging in OTG mode.
Tablet went dead in the car during a test possibly because the OTG cable, or another cable, is malfunctioning.
Might have to go Tasker although I've never gotten it to work properly for anything, and I've never accepted it won't demolish battery polling every few seconds.
Click to expand...
Click to collapse
I use Macrodroid to manage sleep/wake up on mine. Very simple app and easy to understand.
fr4nk1yn said:
Damn. Whatever happened to my tablet it appears to be dead. Won't power on, won't reboot. May be a short lived experiment.
I've ordered hundred of dollars worth of parts for the car so If it doesn't charge by Wednesday i'll have to buy a N7'13 off CL.
Click to expand...
Click to collapse
That's too bad maybe try to plug in to your pc and recognize adb or fastboot or something?

tesna said:
I use Macrodroid to manage sleep/wake up on mine. Very simple app and easy to understand.
Click to expand...
Click to collapse
I going to try it out. I'm quite used to Trigger, I haven't used it in awhile though and not for this type of power control.
tesna said:
That's too bad maybe try to plug in to your pc and recognize adb or fastboot or something?
Click to expand...
Click to collapse
Took it apart after not charging at all. Checked battery voltage, then voltage at the microUSB, tried powering it on, yet again, and it did. I did nothing different, same cable and charger. Wiggling and poking the socket it doesn't appear to have a loose connection.
My new OTG cable is on the proverbial slow boat so I can't eliminate that until early October!

tesna said:
I use Macrodroid to manage sleep/wake up on mine. Very simple app and easy to understand.
Click to expand...
Click to collapse
Care to give your macros for power? It's time to try other methods of forcing the tablet to sleep.
Tasker, as usual, is impossible.

fr4nk1yn said:
Care to give your macros for power? It's time to try other methods of forcing the tablet to sleep.
Tasker, as usual, is impossible.
Click to expand...
Click to collapse
My macro is pretty simple, I just set on charger connect, screen on, run app A,B,C Then another macro on charger disconnect, screen off, close app ABC (killing navigation apps, music, OBD stuff). You can apply also turn on/off airplane mode, turn/off mobile data, wifi AP, etc but I decided to keep them on even when not charging to track the location of my car in case my car got stolen lol. Another macro that I occasionally use is, turning off the tablet when the charger is disconnected (key ACC off). No need another macro since the tablet will auto power on when charger is connected (key ACC on).
Before macrodroid I was using condi, and it was not always working.

@tesna Thanks. While playing with Tasker I found it doesn't actually cause deep sleep, just shuts down radios.
We really need a kernel with some of the newer improvements. And firm sleep.
Since my car isn't a daily driver and only goes out for relatively short trips the tablet will eventually go completely dead.

@fr4nkl1yn, there's simpler solution to that problem. Just set in tasker/macrodroid to turn off the tablet once the ignition key is on the off position (charger disconnected). Bam no battery drain issue...

tesna said:
@fr4nkl1yn, there's simpler solution to that problem. Just set in tasker/macrodroid to turn off the tablet once the ignition key is on the off position (charger disconnected). Bam no battery drain issue...
Click to expand...
Click to collapse
yeah, I'm going to have to do it. close apps and set airplane mode with screen off at power, and a timer to shut down after a few hours. Off_charge_mode will take care of the rest with screen, radios on at power on.
Having an add issue. the tablet is powering the charger, and the key circuit of the car, through the otg cable.
Further research shows its functioning just as it's supposed too. This is also the cause of the issues I was contributing to pem.
When the power is shut off while a otg device is connected, or the tablet thinks is connected, it doesn't sleep and powers the otg device, my charger, from the tablet. At that point it doesn't recognize any change in external power until its physically unplugged and reconnected.
Source, timur: http://mehrvarz.github.io/usb-host-mode-power-management-nexus7/
This leads me to believe pem isn't switching the fixed install trigger, or oxydo-revamp has a bug.