safe Ignition circuit VR exec

trace the ign wire down to there it enters the fuse block. then go either side of one of the fuses. but choose carefully because if its something that draws alot of power you may need to up your fuse amperage

 

The fag lighter in the centre console should be ignition/accessory switched plus it has a big fuse and is easy to get to.

 

+1 I have always done this

 

You could get your signal off the purple (i think) wire off your oil pressure switch, its the one that keeps the fuel pump powered up. Or you could even switch it off the fuel pump wiring.

 

You won't need your multimeter - just pull the brown/yellow tracer wire off the end of the lighter and attach your inverter. The black wire on the lighter is earth.

 

just run a wire from your battery, to where you want the inverter. then inline place a 4 pin relay. standard will do. all you would need to do is cut it where it runs under your dash and put a female terminal connector onto each end that has been cut. then attach the female terminals to pins 87 and 30 on the relay (it will tell you next to each pin which is which). then run a wire direct from your on wire (ign wire). feed this to the relay on pin 85 and then an earth wire from pin 86 to the chassis of your car or any earthed section.

using this method you will have direct power straight from your battery, so you wont have to worry about sucking to much power from the things that run from the ign wire, and it will mean that when the key is off or on acc it wont trigger the relay so it wont be on.

if you need ill wire up one of my relays tomorrow with labels of each wire and where it should go as well as a view of the under side of the relay so you can see the pin layout.

hope this helps.

 

he only wants the inverter to have power when the key is in the on position. eg cig lighter is powered off the acc so this wont work for him

 

I would do this.

As you are running an inverter (to power something 240v I assume) it may draw a resonable amount of current when the inverter is loaded. Using the fuel pump as a trigger will virtually eliminate the risk of accidently flattening the battery by leaving the key on.
Running a fused main supply directly from the battery is a good idea, don't forget to upgrade the earth all the way to the battery post. As you have the supply line running to the boot, you are already close to the fuel pump circuit, use the pump supply line to switch the relay.

FYI pump will run for about 2 sec when the key is first turned on and then turn off if the engine is not running after that.

 

Why not use a 12v power supply for the laptop (Im sure they exist) rather than running it through an inverter?

 

Cig lighter will work with ignition and acc on so should work.

 

hako, read my post again. he doesnt want it to be powered off of the acc circiut. hence why he cant use the cig power. it runs from the acc wire in the key is at acc.

you are correct in that the cig is also powered from the on position.

 

Or.......

you could open up the alternator and pick up the centre of the (star) winding. This should give you enough to power a relay only when the alternator is turning.

 

Yes a dc to dc step up converter is a far better option, I have one and it works well.

Changing 14v into 19v is far easier than changing 14v into 230v then into 19v.

Just be a bit wary of selecting the right voltage on the step up converter, my girlfriend started using a cheap chinese laptop power supply a couple of years ago and the display backlight failed 4 times (repaired each time) before she switched back to a genuine HP charger, and it has not been a problem since. I dont know for sure that the cheap power supply caused the fault, but it certainly looks that way.