How best to get access to IGN Power

[tommax]

Hey Guys,

I'm starting to wire up a few things in the XJ now (Thermo By-Pass, Reversing Cam, Tyre Pressure monitoring, CB etc).
In the rear i have a dual battery setup with a portable AGM that I will connect to a fuse box/block (hopefully on Cup Day) to power leds, compressor, fridge etc.

But in the front I have daisy chained too many things off the cig lighter. I want to have an easy and safe way to access IGN power for future installs.

Any ideas? Experiences? I would appreciate it.

I was going to put a fuse block in the front but there hardly any room even for a small one.

Cheers.

[junglejuice]

You could trigger a relay from the cigarette lighter and have that fused supply feed your accs...

[tommax]

You could trigger a relay from the cigarette lighter and have that fused supply feed your accs...

Just a simple 12v relay?

[Raisins78]

Just a simple 12v relay?

Yep. Run the ciggy wire to the relay coil, earth the other side of the coil.
Run a wire from the battery with a 20-25amp fuse to one of the "switch" terminals (don't believe the 30 amp rating on most relays... They can get hot at 30amps, so better to be safe than sorry)
Finally, use the other side of the switch to power your gear.

For those still confused, the little diagram on the relay will have two symbols.
A box or spiral - this is the coil. It doesn't matter which way you conect the ciggy power and earth, as long as they are connected to the coil.
The other symbol looks like a ramp/jump/drawbridge from a castle etc.
Picture this as a movable part (as it is) and the drawbridge goes up to stop power going through (when the coil has no power) and then it drops down, touching the other side, allowing current flow through (when the coil has 12v on one side and earth on the other.)

[Raisins78]

So...the power wire from the cigarette lighter goes to terminal 85.
Earth to 86.

or the other way round.....

Battery power (fused!) goes to 30.
Power out goes to 87.
87a will have power when the ignition is off, and lose power when the car starts.
You could find a use for this...or just leave it. (you could hook 87a up to a flashing red LED, and mount it in your dash as a dummy car alarm LED for example.
would only come on and flash when the car is off.....it would be a small deterrent and cost about 50c from JAYCAR etc)

[tommax]

So...the power wire from the cigarette lighter goes to terminal 85.
Earth to 86.

or the other way round.....

Battery power (fused!) goes to 30.
Power out goes to 87.
87a will have power when the ignition is off, and lose power when the car starts.
You could find a use for this...or just leave it. (you could hook 87a up to a flashing red LED, and mount it in your dash as a dummy car alarm LED for example.
would only come on and flash when the car is off.....it would be a small deterrent and cost about 50c from JAYCAR etc)

That nice and clear. Cheers. Any gauge cable needed? So I can just keep daisy chaining off pin 87?

[Raisins78]

Use 4mm minimum, run it from 87 to a small fuse block.
The 20amp fuse you put in on the battery wire will protect it to the small fuse block, then run fuses for each accessories rating. 5amp for a UHF etc

[junglejuice]

Just a simple 12v relay?

As raisins said yes, I use 40A or 80A relays myself with no issues, the 40A units like I use in the headlight looms that I make handled my twin 150w aircraft landing lights during my testing phase with no issues, where as a Bosch 30A relay couldn't handle the two of them.
I haven't loaded up the 80A relays yet to see how they would go.
Jaycar sell a "sealed" fuse panel which you could feed from the relay and use that as the fusing for any sub-circuits to you accessories, a bit like the PDC under the bonnet.
Also if you go down that path be very careful of the wire sizes, I only ever use industrial rated cable, so a 4mm2 that I use is over double the actual copper size of 4mm automotive cable which is really only 1.82mm2.
Also place the fuse for the relay feed as close to the battery as practical.
With fusing the fuse is there to protect the wiring, not the device and needs to be sized to suit the wire size.

If you need anymore help don't hesitate to ask.
The 12volt.com is a good source of info although I am of the opinion that they show the relay configuration back to front in regards to 30 & 87/87a, they show the feed going to 87 and the load coming from 30 which to any electrician is completely arse about...

[tommax]

Thanks for the responses guys. I won't have time until tomorrow night to read your comments in full but I appreciate you giving your thoughts. I'll get back to you.

[tommax]

As raisins said yes, I use 40A or 80A relays myself with no issues, the 40A units like I use in the headlight looms that I make handled my twin 150w aircraft landing lights during my testing phase with no issues, where as a Bosch 30A relay couldn't handle the two of them.
I haven't loaded up the 80A relays yet to see how they would go.
Jaycar sell a "sealed" fuse panel which you could feed from the relay and use that as the fusing for any sub-circuits to you accessories, a bit like the PDC under the bonnet.
Also if you go down that path be very careful of the wire sizes, I only ever use industrial rated cable, so a 4mm2 that I use is over double the actual copper size of 4mm automotive cable which is really only 1.82mm2.
Also place the fuse for the relay feed as close to the battery as practical.
With fusing the fuse is there to protect the wiring, not the device and needs to be sized to suit the wire size.

If you need anymore help don't hesitate to ask.
The 12volt.com is a good source of info although I am of the opinion that they show the relay configuration back to front in regards to 30 & 87/87a, they show the feed going to 87 and the load coming from 30 which to any electrician is completely arse about...

Cool. Thanks for the tips on the wiring and fuses too.

So its is advisable to have a fuse block like i have in the back next to the battery. I'm back to my original problem... where to mount a fuse panel in the front? There is just no room.

[junglejuice]

There is plenty of room under the bonnet for a small fuse block, just use some imagination....

[tommax]

There is plenty of room under the bonnet for a small fuse block, just use some imagination....

Fair enough. I'm probably a little impatient and need to look a bit more thoroughly. I'm also running out of grommets to run wires through.

[Raisins78]

Why not run some accessories off the rear battery then? I run my UHF, Stereo amps, Camp lights, fridge and Headrest DVD/TV screens off my rear battery.
UHF can be turned on without the key, fridge too. DVD headrests are keyless also to keep the little one entertained while I fill up etc. Amps draw their power from the rear, but are switched on by the head unit. This way, camp music can be enjoyed without fear of flattening my engine battery.

[tommax]

Why not run some accessories off the rear battery then? I run my UHF, Stereo amps, Camp lights, fridge and Headrest DVD/TV screens off my rear battery.
UHF can be turned on without the key, fridge too. DVD headrests are keyless also to keep the little one entertained while I fill up etc. Amps draw their power from the rear, but are switched on by the head unit. This way, camp music can be enjoyed without fear of flattening my engine battery.

Yeah good idea. Will start playing today. Have a few on-off switches lying about that i can use.

[tommax]

OK i have done something...

Pulled the dash out. Fixed the Thermo By-pass switch (wired wrong) but wreaked the cig lighter aux ign. Stripped the connections back to the first split. Multimeter is saying 0.00. Thought it must be a fuse. Have checked fuse 2 as per manual (nothing in 11 guess that is for the horn) in the fuse box above driver foot well with the multimeter. It beeps so must be ok.

Tried to test the circuit itself by putting the probes in the vacant fuse housing slots but couldnt make it beep. Don't thinks its a problem thought as i tried a few random ones and had the same problem.

The manual says to look at fuse 3 and 6 in the PDC. But the PDC (im guessing the black relay box near battery) has a rubbish diagram on the lid. Any ideas where I should be looking or what i can do?

[tommax]

Is this correct?

http://www.cherokeeforum.com/attachments/f2/142780d1347153114t-pdc-fuse-f18-keeps-blowing-96-xj-pdc-drawing.jpg

[tommax]

OK it seems i have lost all accessory power. I have checked the PDC and all fuses in there. All good. Will look to see if there is a fuse for general accessory power.

[Raisins78]

It will be under the dash. Is it one of the big silver ones?

[junglejuice]

The silver ones are circuit breakers, one is for electric seats, the other is for the blower fan....

[Raisins78]

The sport didnt have electric seats did it?
I have 2 Silver C/B's in mine....

[junglejuice]

You are correct but that is what they are for in the pre-updates....

[tommax]

Blew the accessories fuse, took a bit of hunting and manual reading. Thanks for the help. Also found an unconnected wiring loom in the compartment under the glove box. Was a bit concerned that I had done something as i was rooting around in there installing a TPMS. Got a feeling its something to do with power seat but haven't found it in the manual as yet.