Powering on unit outside of car - MTCB Android Head Units Q&A

Hello,
I recently sold my car and no longer have the need for one of these MTCB units. Like an idiot, I forgot to wipe my information from the unit (Eonon / KLD) before uninstalling it.
The unit is made for plug and play with a Mazda 3. Is there something I can do to power it on without the car, so I can erase all of my information / settings and get it ready for resale. Otherwise I'm not going to feel safe selling it. (Even though I could probably revoke the important accounts from the cloud.)
Thanks.

I used a PC power supply.
You need 3 pins Positive and negative for power and positive for ignition power
Look at the adapter wiring specific for your car and you will figure it out.

DRidilla said:
Hello,
I recently sold my car and no longer have the need for one of these MTCB units. Like an idiot, I forgot to wipe my information from the unit (Eonon / KLD) before uninstalling it.
The unit is made for plug and play with a Mazda 3. Is there something I can do to power it on without the car, so I can erase all of my information / settings and get it ready for resale. Otherwise I'm not going to feel safe selling it. (Even though I could probably revoke the important accounts from the cloud.)
Thanks.
Click to expand...
Click to collapse
dazza007 said:
I used a PC power supply.
You need 3 pins Positive and negative for power and positive for ignition power
Look at the adapter wiring specific for your car and you will figure it out.
Click to expand...
Click to collapse
No need to a PC power supply, an AC Adapter 12v - 2a is sufficient.
Cut the end if the connector and make 3 wire ( 2x positive - 1x negative ).
1 positive, 1 negative wire to the power pins "normally the thin pins" to power up the unit
1 positive wire to the ignition wire to start the unit.

I used a PC power supply, the yellow wires are 12V, black are ground. I just put the battery and ignition wires in the yellow wire plug and the ground in a black wire black on a 4-pin Molex connector.
To turn on the power supply, you have to jumper the green wire to a black wire in the 24-pin motherboard connector.
Make sure the power wires can't touch the ground pins. I kept shorting mine out and took me a couple times to figure out what was happening.

I'm like an absolutely moron with wiring so this sounds fun!
I guess hacking up the adapter is better than never selling the unit anyway. Thanks everyone for all the help.

youtube is your friend when it comes to this.. plenty of video's on it..
I have made one up myself from youtube videos
Sent from my K00C using Tapatalk

Related

How to Modify 1 Amp Car Chargers to show AC Mode

So I was getting a bit frustrated with buying single and dual USB car chargers that were rated at 1Amp/Port and still having the EVO showing USB charging. I have five chargers now and they all show USB Charging while in spare parts. So being frustrated, I wanted to figure out and solve the problem. After a lot of surfing and digging, I came across the answer. If you check out this wikipedia link:
http://en.wikipedia.org/wiki/Universal_Serial_Bus#Power
You'll find the answer in the Battery Charging Specification of the link:
"In Battery Charging Specification,[31] new powering modes are added to the USB specification. A host or hub Charging Downstream Port can supply a maximum of 1.5 A when communicating at low-bandwidth or full-bandwidth, a maximum of 900 mA when communicating at high-bandwidth, and as much current as the connector will safely handle when no communication is taking place; USB 2.0 standard-A connectors are rated at 1500 mA by default. A Dedicated Charging Port can supply a maximum of 1.8 A of current at 5.25 V. A portable device can draw up to 1.8 A from a Dedicated Charging Port. The Dedicated Charging Port shorts the D+ and D- pins with a resistance of at most 200Ω. The short disables data transfer, but allows devices to detect the Dedicated Charging Port and allows very simple, high current chargers to be manufactured. The increased current (faster, 9 W charging) will occur once both the host/hub and devices support the new charging specification."
The key here is shorting the D+ and D- pins. Looking up the USB pinout can be found here:
http://pinouts.ru/Slots/USB_pinout.shtml
So, taking my cheapest charger that I bought from Walmart for $5.99 that had dual ports that said it was rated at 1A/Port, I opened it up and soldered pins 2 and 3 together for each port and put it back together.
So now with my modified cheapo USB car charger I went to the car and plugged it in and plugged in the EVO. Low and behold, it now says it's "AC Charging" and now it will pull the full 1 Amp.
So with the result to my satisfaction, I opened up my other chargers, ranging from three different Scosche chargers and one single port Belkin 1 Amp charger, soldered pins 2 and 3 together, and now all of my chargers are showing "AC Charging" using the "Spare Parts" app.
Once you take the charger apart, it's fairly obvious which pins are 2 and 3. I guess I should have taken pictures of each one as I had it apart so you could see it.
I hope this helps others with getting the full charging capacity out of their 1 Amp car chargers. Because running Google Navigation or apps such as Pandora/Subsonic will really suck down the juice.
Wow.. great info! Thanks for posting that!
What gives you the impression that it's not drawing 1A when on an actual USB port...or vice versa, what guarantees you the 1A after this trick? ...(yes, I'm just trying to see your logic)...
RavenII said:
What gives you the impression that it's not drawing 1A when on an actual USB port...or vice versa, what guarantees you the 1A after this trick? ...(yes, I'm just trying to see your logic)...
Click to expand...
Click to collapse
According to everything that I've read on how the EVO and other phones charge, unless it can detect that the charger is a dedicated charger and not connected to a computer, the phone will only draw a max of 500 milliamps at 5 volts. Most of the time, it will only draw 400 milliamps at 5 volts.
There are a lot of threads here on trying to get chargers rated at 1 amp to actually have the EVO charge at 1 amp. The secret is that the 2 and 3 pins must be shorted before the EVO will even attempt to draw more amperage then a normal USB port.
Though you should only do this mod if the charger is truly rated at 1 amp at 5 volts.
So, if I bridge pins 2 and 3, and ground pin 4...I should be able to get it to pull 1 amp and launch into car mode right?
scl23enn4m3 said:
So, if I bridge pins 2 and 3, and ground pin 4...I should be able to get it to pull 1 amp and launch into car mode right?
Click to expand...
Click to collapse
Just bridge pins 2 and 3. Leave pin 4 alone. You could also mod a cable to do this, but make sure you never plug it into a computer!
The EVO will now see the charger as a dedicated charger and attempt to draw 1 amp. Though, based on what I have been reading, it wil more than likely draw 800 milliamps instead of 1000 milliamps. Same goes for USB charging at 400 milliamps instead of 500.
How did you get the belkin apart??
Can someone describe to me specifically what it looks like on 1A AC vs a 500mA?
I've tried plugging mine into a couple of 1A wall chargers that I have (including the HTC included charger) as well as my car and house 5mA chargers, and don't see the difference on screen.
ntron1 said:
How did you get the belkin apart??
Click to expand...
Click to collapse
I had to use my pocket knife to slip it in between the spring loaded metal ground part and the plastic case. Make sure you identify which side will lift off. The top part is attached to one of the halves and you don't want to pry against that side. Just put a bit of pressure on each side until you can crack it apart. When putting it back together, I had to use some super glue on each side of the case after I had pressed it together. Just a couple of drops on each side and it looks none the worse for wear. Except it now charges at a a full amp (probably 800 milliamps)
Just to verify, this is the Belkin charger in question:
http://www.amazon.com/Belkin-Micro-...3?ie=UTF8&s=electronics&qid=1283093014&sr=8-3
Andy S said:
Can someone describe to me specifically what it looks like on 1A AC vs a 500mA?
I've tried plugging mine into a couple of 1A wall chargers that I have (including the HTC included charger) as well as my car and house 5mA chargers, and don't see the difference on screen.
Click to expand...
Click to collapse
Download spare parts from the market. Under battery information it will tell you which mode it's charging in. Either USB or AC.
ChrisDos said:
Download spare parts from the market. Under battery information it will tell you which mode it's charging in. Either USB or AC.
Click to expand...
Click to collapse
Thanks. I knew I was missing something.
Battery droid will also tell you USB vs. A/C charging.
Andy S said:
Can someone describe to me specifically what it looks like on 1A AC vs a 500mA?
I've tried plugging mine into a couple of 1A wall chargers that I have (including the HTC included charger) as well as my car and house 5mA chargers, and don't see the difference on screen.
Click to expand...
Click to collapse
Go into Settings, About Phone, Battery... It will say under Battery Status (just in case you don't want to download a new app)
SteelH said:
Battery droid will also tell you USB vs. A/C charging.
Click to expand...
Click to collapse
JKGoodrich said:
Go into Settings, About Phone, Battery... It will say under Battery Status (just in case you don't want to download a new app)
Click to expand...
Click to collapse
Thanks all.
Now if I could find my soldering iron, I'll attempt this on my 1A wall charger from a time circa Rio Carbon
ChrisDos said:
I had to use my pocket knife to slip it in between the spring loaded metal ground part and the plastic case. Make sure you identify which side will lift off. The top part is attached to one of the halves and you don't want to pry against that side. Just put a bit of pressure on each side until you can crack it apart. When putting it back together, I had to use some super glue on each side of the case after I had pressed it together. Just a couple of drops on each side and it looks none the worse for wear. Except it now charges at a a full amp (probably 800 milliamps)
Just to verify, this is the Belkin charger in question:
http://www.amazon.com/Belkin-Micro-...3?ie=UTF8&s=electronics&qid=1283093014&sr=8-3
Click to expand...
Click to collapse
Thanks, 5 minutes and worked like a champ.
Ten minutes of looking for a lost soldering iron, and the Rio Carbon's charger now shows AC. Cool.
Thanks. I'm planning a hardwired mod to make a physical mount (out of a $5 ebay belt clip that I'm going to saw the clip off of...) in the empty Nav hole on my car. Have been trying to find a cheap donar USB plug charger to wire straight into the fuse box, and this will make that search easier.
scl23enn4m3 said:
So, if I bridge pins 2 and 3, and ground pin 4...I should be able to get it to pull 1 amp and launch into car mode right?
Click to expand...
Click to collapse
Back to this one about grounding pin 4. I know that in another thread someone mentioned hacking a cable on the mini USB end to bridge pins 4 and 5 (the "X" on the diagrams on the second page linked in the first post) to automatically put the car in "car dock" mode. Any ideas how we could accomplish this at the regular USB plug end, since there are only 4 contacts on that side?
Andy S said:
Ten minutes of looking for a lost soldering iron, and the Rio Carbon's charger now shows AC. Cool.
Back to this one about grounding pin 4. I know that in another thread someone mentioned hacking a cable on the mini USB end to bridge pins 4 and 5 (the "X" on the diagrams on the second page linked in the first post) to automatically put the car in "car dock" mode. Any ideas how we could accomplish this at the regular USB plug end, since there are only 4 contacts on that side?
Click to expand...
Click to collapse
Glad to see that the modified charger is showing AC. Afraid I don't know about the car dock mode. Haven't researched that yet.
Thanks again OP. Just modified one and it worked perfectly.
ChrisDos said:
Just bridge pins 2 and 3. Leave pin 4 alone. You could also mod a cable to do this, but make sure you never plug it into a computer!
Click to expand...
Click to collapse
I don't think you understood my question...Grounding 4 (same as bridging it to 5) should kick the phone into dock mod. So if I can pull an amp and get it into dock mod in my car, it'd be perfect.
Andy S said:
Back to this one about grounding pin 4. I know that in another thread someone mentioned hacking a cable on the mini USB end to bridge pins 4 and 5 (the "X" on the diagrams on the second page linked in the first post) to automatically put the car in "car dock" mode. Any ideas how we could accomplish this at the regular USB plug end, since there are only 4 contacts on that side?
Click to expand...
Click to collapse
I believe pin 4 doesn't get used so it's the one missing on the regular USB side...Based on that it would make sense for a wire from pin 4 to not extend all the way. You might just be stuck with with opening it towards the micro usb end.
My htc wall charger shows AC charging. So does my motorola car charger. Do I need to modify anything??
Sent from my PC36100 using XDA App

[FAQ] Charger mod, howto USB fast charge.

I know this is mostly common knowledge but I still see many questions regarding this come up, so instead of explaining this over and over I can now link to this and flame away.
anyway...
When you charge your phone using an original HTC wall charger you phone gets all the power it needs to run itself and charge (up to 1000ma).
When you charge from any (most) other devices (this includes car chargers,non HTC wall chargers or any USB port) your phone will draw up to 500ma (the USB standard) REGARDLESS of the devices output.
The reason why the phone only draws 500ma on USB is so it does not damage any equipment by drawing more power than it can output safely (by design anything with a USB port can safely output 500ma).
The trouble is pretty much all equipment can safely output more than the USB standard of 500ma and safely charge your phone at full speed.
The phone distinguishes between an original HTC charger and other devices by whether or not the data wires are shorted (connected to each other).
How to do the charger mod.
Disclaimer: I take no responsibility for anything that may happen as a result of doing this, by following these instructions you will be pushing any device you charge your phone from beyond the USB specifications, results of this may be, but not limited to your motherboard bursting into flames, you car exploding, the inventor/s of USB knocking on your door and slapping you in the face, but most probably faster charging and not a lot else.
Get yourself a short USB extender wire, male at one end, female at the other.
Cut the wire in half.
Connect the red and black wires up as they were before (or don't cut them in step 1).
On the Female side of the wire connect the green and white wires together.
On the Male side of the wire simply leave the green and white wires connected to nothing.
Insulate the ends of all of the wires with insulating tape.
Tie a knot in the wire so if the wire is pulled the knot is pulled and not the connection you made, it doesn't look pretty but the wire will last a lifetime this way.
All done, now use this wire in between your desire and whatever you want to charge from and get a full speed charge. You will lose data connectivity when using this wire.
There are other ways of doing this, for example.
Soldering together the data pins (middle 2) on the device you wish to charge from. Don't do this on your laptop...this method is intended for car chargers, wall plugs, and external USB battery packs.
Soldering together a male and female USB port and plug directly with no wire in between, this can look really good if you know what your doing.
Great guide! Just a quick question I have a 3rd party USB cable but an official htc wall plug. Will my desire still get 1000mA? Or will it only get 500 because of the 3rd party charger?
ste1164 said:
Great guide! Just a quick question I have a 3rd party USB cable but an official htc wall plug. Will my desire still get 1000mA? Or will it only get 500 because of the 3rd party charger?
Click to expand...
Click to collapse
I have a 3rd party changer and I did this mod and it's working really great it's charging really fast
ste1164 said:
Great guide! Just a quick question I have a 3rd party USB cable but an official htc wall plug. Will my desire still get 1000mA? Or will it only get 500 because of the 3rd party charger?
Click to expand...
Click to collapse
The original charger shorts the data pins so it doesn't matter what cable you use.
Hi,
just wanted to say thank you for the idea. For me this is really usefull in some situations at work, where I have no access to a socket, but a pc.
It charges not as fast as the AC charger, but MUCH faster, than the usual 500mah USB method.
And so does it look like:
fileden.com/files/2006/9/25/238757/charger2.jpg
fileden.com/files/2006/9/25/238757/charger1.jpg
TrTech said:
just wanted to say thank you for the idea. For me this is really usefull in some situations at work, where I have no access to a socket, but a pc.
Click to expand...
Click to collapse
And next time, use your brain first, please.
Do you have an idea why the HTC Desire does limit the current to 500mA if it's not connected to a dedicated charger which shorts the two data pins? Ever thought about it? Ever?
Umm... yes. But please feel free to enlight me.
TrTech said:
Umm... yes. But please feel free to enlight me.
Click to expand...
Click to collapse
umm, and I thought the post starter already answered this question:
The reason why the phone only draws 500ma on USB is so it does not damage any equipment by drawing more power than it can output safely (by design anything with a USB port can safely output 500ma).
Click to expand...
Click to collapse
So in other words:
Any laptop or computer can output max. 500mA by USB specifications.
So this means:
You can have luck and your computer doesn't get damaged if more current gets requested, it just limits the current to something around 500mA.
You can have luck and your computer just shuts down the USB port and Windows reports you that a malfunction device got connected.
You can have bad luck, most often the case, especially on cheap notebooks, netbooks, computers, a fuse will prevent bigger damage and the USB port remains dead until the rest of it's computer live.
So the limit got wisely chosen. So if you want to use your USB ports in the future, too, then only use this 'trick' on wall adapters which support an output current equal or larger than 1A (1000mA), or use it only in combination with USB ports which support that high currents (most often advertised as being able to charge the Apple IPad), most often found on external USB hubs.
UpSpin said:
umm, and I thought the post starter already answered this question
Click to expand...
Click to collapse
Me too. Its all written in the first post and I'm doing it on my own risk. Still wondering about your raging post.
I will update this, as soon as the first pc was fried.
TrTech said:
Me too. Its all written in the first post and I'm doing it on my own risk. Still wondering about your raging post.
I will update this, as soon as the first pc was fried.
Click to expand...
Click to collapse
I was that 'unfriendly' because other people will do the same, because person xy said that it works. Then they fry their mainboard or notebook and complain.
I also don't understand why anyone risks damaging intentionally its computer or parts of it, especially if there's absolutely no need for it, e.g. just let it charge in USB mode, or take a small charger with you, or at least use two USB ports to separate the load.
But well, maybe some people don't have to take care of their computer.
This is an interesting thread. I have a Pebble charger and it literally takes four hours to charge my 1400mAh from ~0% to 100%, now my question is, will this damage my Pebble charger shorting the two wires to draw a greater current from the unit?
Overheating, melting and explosions are something I am looking to avoid.
I have yet to find a device that has been damaged doing this. I have personally tried this on a ps3, Xbox wii, 4 laptops 2 desktops, car radio,car charger and a sky+ box.
Kalavere said:
This is an interesting thread. I have a Pebble charger and it literally takes four hours to charge my 1400mAh from ~0% to 100%, now my question is, will this damage my Pebble charger shorting the two wires to draw a greater current from the unit?
Overheating, melting and explosions are something I am looking to avoid.
Click to expand...
Click to collapse
Did you try this? I too have a Pebble and would be interested to know if I have just 30 minutes to plug it in, can I charge quicker.
Also, did the guys PC blow up? He said he would come back!?!? Maybe it did and he's in hospital still Dangerous things USB ports...
thanks for this ! I go to try this
MM i have an interesting one (which i still dont get)
i have a pebble charger
with OEM HTC Micro USB charger cable
and Pebble charger
plug phone into OEM micro USB charger to phone (phone says Power AC) yeh thats right
OEM Micro USB to computer (chargin USB)
So far so good
Pebble charger OEM USB to phone (chargin USB)
Pebble Cable charger to phone ( Power AC)
why are the OEM and Pebble charger cables different?
Sorry if i am posting in the wrong area but the topics seem pretty similar to me =P
to put my 2pence in, i've just done this but slightly different than the OP method..
i bought the belkin car charger, gives 1amp, but is detected as 'USB', not 'AC' charging mode, so my phone only charges upto 500ma which isnt enough (in reality it doesnt charge when i have GPS & max screen brightness).
instead of modding a USB cable (unable to use for data) or buying extra kit (money/ordering/going out) i pulled a strand of wire from a spare mains cable i had, threaded it through the 2 center pins on the belkin charger and then twisted the wire together.
USB cable is slightly tighter in the socket now, but still removable and keeps everything nice and tidy.... and more to the point; cheap!
poor shown from belkin; 'USB charger' mode in a car! like it would ever have data connection to the 12v socket.
hope that helps someone!
USB cable to quick-charge an HTC smartphone
Check http://winhlp.com/node/855 for some more details and photos of a USB cable modification.
Does this mod change the detection of car mode
Hi,
I have just started flashing a couple of roms and noticed that when using my desire with my car charger (1amp rated) it does not charge when doing navigation. looking on battery widget I get a max 289mw on car charge and it is showing as a USB charge. Flashed back to stock and now the car charger shows up as ac connected rather than USB. This does solve the discharging on navigation issue but I would like to run Gingerbread.
my question is...
Will this mod stop the Desire detecting and automatically entering car mode when it is plugged in? Anyone done it to their car charger?
Ta
Yes
The cable modification (shorting the data lines 2 and 3, instructions at http://winhlp.com/node/855 ) will switch any HTC smartphone into AC charging mode.
But I am totally stumped as to why you can achieve AC charging mode without this mod. I know of no other way the HTC phone could detect a car USB charger. I'm tempted to ask you to repeat the test.
If anybody here has any idea, please respond. To the best of my knowledge no USB device is allowed to pull more than 0.5 A from USB power, lest the power source switch off according to the USB specification. The only exception is that the device gets positive information that it is connected to a charger that can deliver a higher current, and for HTC devices that is signalled by a shortcut between the two data lines.
Thank you. I would rather not check again I did look for a while. Reverted back to stock for now.
It is a Huawei curly lead car charger with a 1a rating. The strangest thing is that with my stock Vodafone rom it detects as AC power on battery widget but on both leedroid and RCMix it shows up as a USB charge and I get the power issue. On all three roms it detects car mode correctly (Which is good!).
I was just wondering if the mod would also break the car mode detection?
I can't find anything on how car mode is detected!

[Q] Docking station broken, is it repairable?

Hi,
My made-in-china docking station has just arrived, unfortunately its already been broken (quality material of a matchbox :\),
I have plugged in my micro usb into the socket (female micro usb on the dock) and somehow after few tests the female receiver of the dock fell out.. (I guess it wasn't glued strong enough because I haven't use any extra power to push it in)
Any way.. I have opened it up to see whats going on and found this:
http://img841.imageshack.us/img841/9554/a84p.jpg
The small piece on the left is the female micro usb plugger that was attached to the green board but fell off..
This is a sort of explanation:
http://img856.imageshack.us/img856/2971/4wbl.jpg
And thats the part it self:
http://img43.imageshack.us/img43/8735/ew44.jpg
Unfortunately I can't glue it back and definately not weld it on since its too tiny and I don't have proper equipment for that..
But I do want to try to fix it because god damn its 1 day old ! totally brand new!
So I was thinking maybe I should simply tear a cable and plug the + - to the red and black wires at the end of that board..
And so, here comes the question for you expert fellers.
First this is the board:
http://img856.imageshack.us/img856/8915/xo1u.jpg
I have a basic knowledge in electricity but its from engineering study and not from real world, so I don't really know how to read this thing..
Perhaps a better intuition than mines will help too..
Is this board necessary? What does it do? and can't it live with out it?
Why they didn't simply plug the + and - straight to the + - pins of the docking points?
Because thats what I am willing to do but I guess that "Ask the experts before you ruin it" is a helpful tip my mom taught me..
Thanks!
Jordan.
I'm curious about this too. I'm in the same boat as you: basic knowledge but not too much real world experience. So, I can't tell you what the board does, but maybe we can figure some things out and perhaps someone with more knowledge will chime in eventually.
I can at least answer (I think) why you don't just have a red and black wire going to the point where the phone docks: you have data too (assuming the dock does data as well as charge). Those are the green and white wires in USB.
Well actually I have already figured out out..
First of all there is no data..
You can't minimize 4 cables to 2, its not possible in any way..
Those two pins are for charge only..
The board is for security defense, if you plug into it something with high voltage, it shuts it down or something.. Or transfor only the needed voltage and ampher (5v and 1A for me)..
Any way I cutted out that board and opened up a micro usb cable on the microusb side, attatched the red (+) to the dock's red and the brown (could also be white blue or somwthing, check it out to be sure) to the dock's white (-), closed every thing nice and tight, plugged the usb to charger with 1 ampher output, and it worked..
My phone is getting charged nicely and showing up Docking signal as well..
I'm not sure what exactly this board does and if its useless or not, but it sure ain't must..
Good luck!
Sent from my C6603 using xda premium
Makes sense. I kind of expected there to be no data (hence why I made the comment about it ) Glad you figured it out!

Hardwiring a car charger (USB 500mA vs 1A)

I'm trying to figure out what the best way to implement a hardwired charger.. more specifically in terms of getting the most mA as I can. What I understand is that when the data pins on a USB charger are floating, the phone requests only for 500mA. When the data pins are shorted, the phone requests for 1A (or 1000mA). On any decent 5v ciglighter /wall outlet phone charger, I understand that the charger shorts these data pins, allowing for that full 1A charging capacity.
I plan to use one of these ebay 12v to 5v converters:
http://tinyurl.com/oogbhyn
..and splice a standard micro-usb connector to the 5v output, also connecting both data wires together.
If I understand this correctly, would this provide 1A to the phone? Does anyone see any implications?
Thanks!
Smiert said:
I'm trying to figure out what the best way to implement a hardwired charger.. more specifically in terms of getting the most mA as I can. What I understand is that when the data pins on a USB charger are floating, the phone requests only for 500mA. When the data pins are shorted, the phone requests for 1A (or 1000mA). On any decent 5v ciglighter /wall outlet phone charger, I understand that the charger shorts these data pins, allowing for that full 1A charging capacity.
I plan to use one of these ebay 12v to 5v converters:
http://tinyurl.com/oogbhyn
..and splice a standard micro-usb connector to the 5v output, also connecting both data wires together.
If I understand this correctly, would this provide 1A to the phone? Does anyone see any implications?
Thanks!
Click to expand...
Click to collapse
In theory it should work OK.
I would recommend a few things. Make sure that dc-dc converter is easily accessible if you need to check it or smell a smoke in the car. Don't bury it too deeply where you will have to take too many things apart to get to it. I made plenty of mistakes in the past where years later wire cracks or connector is not making a good contact and I have to take the whole damn thing apart to get to it Also, I would STRONGLY recommend to add in-line blade fuse, like this: http://www.ebay.com/itm/Waterproof-..._Video_Fuses_Fuse_Holders&hash=item3f2dc85fa3
The last thing you want is to damage your phone if you get some in-rush spike. DC-DC converter looks ok, but you never know what could go wrong if it overheats and something shorts out. At least you will have a fuse to protect your 5V power supply line going to the phone. And since blade fuses are replaceable, you just pop in 1.5A or 2A, obviously don't use 10A that comes with it.
Once you done, comeback and post some DIY pics!!!
I was planning to use these add-a-fuse circuit extensions. I'll be sure to pick up some 2A fuses (supposedly the smallest fuse for mini-fuses)!
I want to actually hardwire chargers for two things into my car; my phone, to the left of the steering wheel dash, and a recently acquired dashcam right next to the rearview mirror. I drive a little Mazda so space isn't plentiful. The fusebox is to the left of the driver's left foot, so I planned to wire two add-a-fuse circuits; bring one up 2~ feet before the windshield pillar (phone), and the other along the pillar, over the headliner, where it would go to the 5v converter, and then bring the mini-usb cable where the headliner and windshield connect. There really isn't much I can work with..
Do you think that sun damage would damage the exposed cable? Perhaps it would be better to have an exposed female-usb outlet "installed" and use adapters to charge the electronics?
Smiert said:
I was planning to use these add-a-fuse circuit extensions. I'll be sure to pick up some 2A fuses (supposedly the smallest fuse for mini-fuses)!
I want to actually hardwire chargers for two things into my car; my phone, to the left of the steering wheel dash, and a recently acquired dashcam right next to the rearview mirror. I drive a little Mazda so space isn't plentiful. The fusebox is to the left of the driver's left foot, so I planned to wire two add-a-fuse circuits; bring one up 2~ feet before the windshield pillar (phone), and the other along the pillar, over the headliner, where it would go to the 5v converter, and then bring the mini-usb cable where the headliner and windshield connect. There really isn't much I can work with..
Do you think that sun damage would damage the exposed cable? Perhaps it would be better to have an exposed female-usb outlet "installed" and use adapters to charge the electronics?
Click to expand...
Click to collapse
I have my Passport X50 wired through a-pillar. It's not usb, but 12V tapped off cigarette lighter internal wires so I can use another usb converter plugged into a cigarette lighter.. l was able to run the wire under upholstery of my GS350, but it was kind of tricky. I actually used credit card to push it in along the edge. Otherwise it would not look clean, and will be exposed to a sun - in my opinion sun damage is a problem. Perhaps get one of those cigarette lighter to AC adapters and use something like that 40W 5-port Anker wall charger I just reviewed?
I want to do the same, but for a dashcam.
Can I tap in to the power line that goes to the auto dimming rear view mirror and connect something like this to it?
Does the converter comes with a fuse or do I need to add an additional fuse?
Thanks in advance

Nexus 7 2013 (wifi) no battery mod - car install - otg - power problem

Hi there everyone,
I have been trying to get my Nexus 7 2013 installed into my car seamlessly without problems since December 2015. I have Timur's Kernel v4 (6.0.1) running on it, and it was working flawlessly.
However, I decided that the no battery mod needed to be done as I just could not leave that battery inside a hot car - way too risky.
So, I did the Kevdav no battery mod - with success.
However, once the battery connection was receiving 5v via a usb car charger the OTG cable connected to the tablet's mini usb port would not wake/suspend the tablet properly. It would wake it up, but once it was awake the little battery icon at the top would forever show that it was 'charging' and once power was cut to the otg y cable / mini usb, it would not suspend (would still show as charging).
I did research, and bought a Drok DC-DC step down converter. I lowered the voltage to the battery mod connection to 3.7v (and tested up to 4.7v) and this alleviated the problem of suspend/wake. I think since the original battery gave out less voltage then the otg/charging connection, this needed to be replicated in order for the otg to work.
However, I now have a new problem that I cannot seem to fix. This problem only seems to happen in the car and does not occur when testing it in the house using normal wall chargers.
For clarity, this is how everything is wired up in the car.
Nexus 7 battery mod side of things:
Nexus 7 battery terminals > 22awg usb cable > drok dc dc step down power supply (this board has a female usb port for output) set at 3.7v (tested up to 4.7v) > input is connected to car's constant 12v connected directly to battery on a fused wire.
Nexus 7 mini usb port side of things:
Nexus 7 mini usb port > usb otg y cable > mini usb cable > 2.4a usb car cig adapter hardwired to car's switched 12v accessory wire.
The link to the drok dc dc step down is this - https://www.amazon.co.uk/dp/B01FDBY66Y/ref=twister_B01GO268W6?_encoding=UTF8&psc=1
I turn on acc ignition to send power to the otg connection. It'll power up. However, if left in standby overnight the tablet won't power up. If I physically press the tablet's power button it'll wake up, show the wake up animation, and react as normal (including any subsequent power downs). However, if I don't press the power button and I turn off the ign again, an icon on my car's instrument cluster will be faintly illuminated - this is odd behaviour and should be completely out. When this is the case, if I get out and try to lock the car the remote central locking doesn't work.
This light will go out if I physically disconnect the otg y cable from the tablet, and low and behold the remote central locking works.
I'm no expert on electronics and such, but it seems to me that power may be flooding back into the OTG connection from the no battery mod power?
Does this make sense? Sorry for the long question, but I was wondering if anyone had any experience with troubleshooting or any advice? I've this one problem and then I'm set but I just can't seem to figure anything out and need someone's advice who is in the know rather than take wild stabs in the dark using my own logic because if I do the latter, not only will I waste money on needless components but I'll more than likely break something. I've read stuff about diodes or something in order to regulate power flow but I'm not even sure I'm using the correct terminology here so if anyone can tell me I'm onto something here or I'm talking complete nonsense then anything is appreciated!
I did search these forums and google but I really cannot find anything that is similar to my problem.
Thanks for any input guys, whether it be any tips on what I'm missing or what I need to change (software or hardware, electrical, etc) - it's all very much appreciated.
Antony
Edit: so sorry I think I posted this is the wrong n7 2013 sub section. I can't delete the post but if a mod could please kindly move it to the relevant forum I'd appreciate it. Thanks!
antc101 said:
it seems to me that power may be flooding back into the OTG connection from the no battery mod power?
Click to expand...
Click to collapse
Hi, indeed, and your "2.4a usb car cig adapter hardwired to car's switched 12v accessory wire" requires a small mod to prevent the power feedback. It needs an extra 1A+ diode connected directly to 12V input. You could modify the adapter's PCB or simply replace the fuse's internal wire with a diode where its cathode goes to the spring and its anode to 12V input. Or just place the diode somewhere along the adapter's hardwire. $0.16 1N4001 is good enough ([email protected] is OK for [email protected]).
Not sure if thread is still active but I also have the same symptom with tablet turning off completely overnight. I am running constant 12v to 3.7v dc to dc on battery input and car adapter 12v to 5v on microusb cable in. Tablet will work fine with on and off but after car is shutdown for the night it will not turn on in the morning. It shows me battery charge icon only. I dont have diode installed either. Not sure if thats the cause. Anyone know why it would completly shutdown overnight?
Neo2020Marz said:
Not sure if thread is still active but I also have the same symptom with tablet turning off completely overnight. I am running constant 12v to 3.7v dc to dc on battery input and car adapter 12v to 5v on microusb cable in. Tablet will work fine with on and off but after car is shutdown for the night it will not turn on in the morning. It shows me battery charge icon only. I dont have diode installed either. Not sure if thats the cause. Anyone know why it would completly shutdown overnight?
Click to expand...
Click to collapse
Hi there,
Been a while since I posted on this thread but just wanted to update on what I have done so far.
Since my last post, I don't have any issues. I placed a diode as mentioned above on the +12v for the accessory power. This seemed to have fixed any back flow of power.
Concerning the power off over night, I'm pretty sure this was something to do with Timur's kernel. I forever had issues with that thing - eg, suspect and wake issues, accessories connected to my usb hub..
I switched to a stock version of android 6.0.1 - MOB30X if memory serves... and installed Elemental X version 5.16. No issues with this setup what so ever.
Huh.
I run my Nexus 7 on my car with the battery, mounted just above the dashboard, with direct sunlight exposition and no UV film on the windshield. It's been a whole year without issues, thank God.
https://i.imgur.com/cPNhDDc.jpg
I live in the Northeast of Brazil, where's 30C to 40C through the year. Sometimes I come up to the car and the tablet shut off due to the heat.
Battery still lasts wonders and there's no signs of damage.. yet.
Is it really adamant to remove the battery, or is it just a precautionary measure?
GTMoraes said:
Huh.
I run my Nexus 7 on my car with the battery, mounted just above the dashboard, with direct sunlight exposition and no UV film on the windshield. It's been a whole year without issues, thank God.
https://i.imgur.com/cPNhDDc.jpg
I live in the Northeast of Brazil, where's 30C to 40C through the year. Sometimes I come up to the car and the tablet shut off due to the heat.
Battery still lasts wonders and there's no signs of damage.. yet.
Is it really adamant to remove the battery, or is it just a precautionary measure?
Click to expand...
Click to collapse
You better have more luck.
My nexus was put under the dash and was fine for around 3 years. And it became expanded in just 2 days, separating the screen and the case. So I have urgently remove the battery.

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