Finding/splitting a 12v supply to power Tablet

[che47audio]

Hi there,

I recently started to install a Nexus 7 to be used as a head unit in my car. I have it fitted and looking nice with the line output running to the aux input of my car stereo which is now mounted in the glove box. Now I just need to power it!!

So my questions are,

- can I split the 12v that currently feeds the ISO connector to the stereo and use an adapter to get the 5v 2a that I need? Or is this dangerous?

- It would make sense to use the "switched" 12v volts so the tablet is only powered when the ignition is on. Agree?

- If I can't use the twelve volts that is currently powering the car stereo at the same time, where can I get power from?

Thanks for your time

Most appreicated

Chris

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[bradl79 10+ year member]

That sounds cool can u take pictures

 

[che47audio]

Here is one.

 

[CrossoverOre 10+ year member]

dont do that. just go and get one of these.

Scosche reVOLT c2 Dual USB Car Charger Review - reVOLT c2 Dual USB Car Charger - Legit Reviews

I have one in may car and works great. plus you get 2 usb charge ports

 

[che47audio]

Good shout. I was just thinking I would make sense if the tablet was only getting power whilst the engine was running. I can set the tablet to sleep when there is no power and wake when it sees ac power. So if I hard wired it, it would wake/sleep when the ignition was on/off. Otherwise I have to unplug it every time I leave the car.

Thoughts? I should have probably mentioned that this tablet is permanently mounted in the dash.

Cheers

 

[bradl79 10+ year member]

Is Ur tablet rooted?

 

[che47audio]

Yep. It is.

Does anyone here know if its ok to take the 12 volts from the stereo harness? It would be sharing that 12volts with the Sony head unit that I am using for the aux input and probably radio.

Thanks again

 

[maylar 10+ year member]

You would be fine with your original plan. Tap into the 12 v switched power line going to the HU.

 

[CrossoverOre 10+ year member]

I just soldered wires directly onto the contacts for the usb charger and tapped the power at the deck.

 

[che47audio]

Thanks for your responses. Please could you explain in more detail the points at which you soldered on to the usb charger as this is what I plan to do . And tapped the power at the deck. What does that mean? This may be easier than I had orignally thought! Exciting!

Cheers

 

[CrossoverOre 10+ year member]

picture the cig lighter plug car charger. on the tip is the + contact and on both sides of it are the - contacts. I just solder wires to those contacts and connect them to power and ground. you will have to find a switched 12v but you can find ground pretty much everywhere there is metal in those vehicles.

 

[che47audio]

Cool. So I can solder the tip of the cigarette adapter to the "switched + 12v" and solder the "-12v" to one of the sides?

Cheers

 

[CJL 10+ year member]

install looks good. How do you have it mounted?

 

[Lexicon740iL 10+ year member]

1. You need to feed that USB plug that goes into your tablet 5V not 12V

2. Use a cigarette lighter to USB plug adapter like mentioned previously to knock you 12V feed down to 5V for your USB cable into the tablet.

3. If you want to hide everything just use a female 12V cigarette lighter adapter that terminates into bare wires or get one with a trailer plug or something and cut the end off and wire it into the 12V Switched and Ground of the harness for your stereo.

Like this

Hook one of these into your 12V switched and Ground on the stereo harness

Then hide it behind the dash and plug one of these into it

Now plug your tablet usb cable into the USB adapter and heat shrink the connection.

Voila

12V to 5V USB rail hidden behind dash and the lead is only charging or hot in key position 2.

But keep in mind just because the car is off it wont turn your tablet off it just wont charge. You will still have to power down you device manually for a full off or just let it go to sleep.

Hope this helps. I have hooked up tons of A/V retrofits into OEM screens/Navi head units in my BMW's this way.