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Discussion Starter #1
Switched 12v power in Ampera boot ?

I’m looking to try and mount a cheap rearward facing dash cam, and wondered if anyone knows of an easy switched source of power I can use for my dash cam wiring ?

Thanks :)
 

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Ampera aka IGOR
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I don't know of one but it might be worth just rigging up a bulb one cable to earth (would come in handy for the camera too and then poke the fuses until you find one that is power on with the car. There is a fusebox behind the left-hand side panel in the boot. F12, according to the handbook, is for the rear windows. F15, F17 & F18 are empty according to the manual so one of those may be powered up with the car.
 

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Discussion Starter #3
ok, cool, well it started raining earlier when I was having a look, but all the ones I poked at with the multi meter were powered with the car off, and the one I found which wasn't powered, also didn't seem to be powered with the car on. I'm not great with this stuff but will take a closer look at it again tomorrow :)

thanks

Paul
 

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Ampera aka IGOR
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It's page 160 of the PDF manual I have. There are some feeds in there for things that you would expect to be live with the car powered off but the one I mentioned I would have thought it would be car powered dependent.
 

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Discussion Starter #5
thanks for your help with this, yeah, I've found that page and am looking at it, based on what most of that stuff is, I would have expected most of it to be ignition controlled ?

eg :


F6 Fuel (Diurnal valve and evap.
leak check module)
F7 Accessory power module cooling fan
F8 Amplifier
F9 Digital audio broadcast
F10 Regulated voltage control/ Ultrasonic front and rear
parking assist F11 Horn
F12 Rear power windows F13 Electrical parking brake F14 Rear defog (Upper grid) F15 –
F16 Tailgate release
F17 –
F18 –
 

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ok, cool, well it started raining earlier when I was having a look, but all the ones I poked at with the multi meter were powered with the car off, and the one I found which wasn't powered, also didn't seem to be powered with the car on. I'm not great with this stuff but will take a closer look at it again tomorrow :)

thanks

Paul
You may find that many supplies are on when the car is being fiddled with i.e. doors opened etc so leave it for ten minutes and check again as modern cars are notorious for powering up when sensing a door opening. They go into battery save and power down when left alone.
 

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I had a good hunt for a switched 12V in boot, couldn't find one. I did find a switched 2.5V DC signal inside the DAB box under the boot floor! So I used that to drive a MOSFET which then switches one of the permanent 12Vs from the fusebox. Circuit diag & pics in "Eliminating the Double-Beep when Charging Starts" thread.
 

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Ok, again in words of one syllable! As I couldn't find the same thing you're after, I took the lid off a promising looking box under the boot floor, which has an aeriel lead coming into it. My son googled the long number and identified it as the DAB radio decoder thingummy, as fitted to tons of Astras etc, so should be cheap as chips to replace from a scrapyard if I blew it up. Poking around inside with my voltmeter, all I could find that got switched on & off with the ignition was a 2.5V pin.

You don't want to just wire in a relay to that; every chance you'll overload something. But there are wonderful electronic transistors called Mosfets (Metal Oxide Semiconductor Field Effect Transistor) which only need a voltage signal to switch them on. Perfect for the job. You can switch them on by just touching the control pin with your finger! So one of these can be connected to that low power 2.5V pin inside the radio box, and then the mosfet can switch the considerable amount of power (maybe half a Watt, whatever) needed to power a proper car relay connected to the permanent 12V in the fusebox. Has this made it clearer?
 

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Discussion Starter #12
That sounds interesting, would that source not turn on the standard auto relax I have sat on the shelf in the garage, or is that looking for 12v

So this thing is a MOSFET relay ? Got a link to one ?

Many many thanks
 

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