A question for those of you who are more "electrically inclined"...

My Expedition had power ports that turned off with the key except one (the actual cig lighter).

I like not having to worry about draing the battery if I forget to unplug something, and I can appreciate where Ford was coming from having them on all the time.

The question is...if I run a lead from a switched outlet on the fuse box (add-a-tap, etc) to relays placed near each outlet behind the panels, couldn't I add a switch that would use the "always on" power and have he switch decide if the outlet was getting power via the key? ...wouldn't that let me decide at each power port which ones were constant on vs switched?

I'm picturing a three-way switch (on-off-on) that the On1 would be straight through (always on)...Off would be, well, off...and On2 would be put power to the relay making it switched. I think I also need to add a couple of diodes in there, but it should work.

...right?

 

This is what I'm thinking...do you electrical guru's think it would work?


Also wondering if I could get a different type of switch that I could use to only activate the relay when it's in 'Keyed' mode...in this diagram the relay will "open" every time you turn the key to the 'on' position...even if the switch is set to 'always on'. That would in theory wear out the relay prematurely.

I'd like to find a switch that when you select it to be the 'switched' position (vs 'always on'), it would also then route the fuse block line in the "on" position, letting the relay activate, but when in the 'always on' position it would not let power to the relay trigger.

 

As long as the "existing power line" and the line coming off of the 87A pins are different sources (hot and ignition switched) it looks like it would work. If you want to use a switch like you mentioned, you could run it inline with the fuse panel and 86 pin in your drawing above. You would have 2 (+) inputs, one always hot and the other ignition switchable. When you have the switch in the "always on" position, it would always charge the relay. When you have it set to the "ignition" position, it would only charge the relay with the ignition on. One thing to be careful of is the existing power feeds you are using can power what they intend to power in addition to what you want to power at the ports. Otherwise, you may want to run a new fused wire to the battery.

 

I think 87A would need to stay disconnected...connecting it to anything would have the same effect it has now - always on.


That is what I am trying not to do...if the switch is in the "always on" setting, I want the relay ignored (why charge the coil and "wear our" the relay when it isn't doing anything?). I am hoping to find a switch that basically has two circuits simultaneously...when in "always on" it sends no power to the relay coil...when in "ignition on" it routes power ro the relay hot and the relay trigger. I had a switch for some backup list in my Expedition (on-off-on) that had 6 contacts...one set was higher amp than the other set...I think that would work. When I described the project the guy just got the switch - didn't think to write down what it was called.

That is why there would be one of these setups at each power port - I could set each one independently without accidentally messing with something else that may be run from that same fuse. I am picturing a switch below the ignition but above the fuse panel that would control the one in the dash (not the cig lighter, the other one), another under the one in the back of the console below the power port, and a final one in the back near the rear one. That would let the cig lighter run all the time, but the other three would be "user settable".

 

Get 2 batteries. I've left numerous devices plugged in, and on, for days on end. Never an issue. Hell, I left my truck in the run position(while off) priming glow plugs, for 4 hours, on accident of course. I came out and realized what I had done, radio was on and everything. I thought surely it was dead. A little slow to turn over but fired right up and not an issue after that. Have you experienced a dead battery due to leaving something plugged in before?

 

No, but I will be running a light bar on the roof (4 strobes, 8 segment halogen TA), 4 grille LED's, rear strobes and LED's along with side warning...could weaken a battery and if I turn everything off without starting to recharge and leave something plugged in, I don't want it to be dead. I'll be abusing the battery something wicked, last thing I need is a dead battery while doing what I do...

 

Sounds like you're a great candidate for a second battery mod on the V-10. Then, you'll never worry about the starter battery being dead. Just use and isolator kit and a deep cycle battery for all your radios and lights.

 

Oh yea...already working on the 2nd batt...thinking about the E350 battery box mod

 

Sorry for the crude drawing. I didn't put the contact numbers on the relay, but the position is standard on most, make sure you have one with all 5 contacts. When switch is off, power comes from Ign, when switch is on relay connects power point to constant power. I try not to use diodes directly powering anything with much current draw, they can get hot and burn up, especially any kind of light.

 

I cant post the pic, working on it

 

http://i1086.photobucket.com/albums/...erpointpic.png
Thats a link to the pic i made

 

Is that box on the left a switch?

 

Yes, sorry. Drew it quick.

 

Looks like in your pic the power would be on to the coil of the relay all the time and would give me only two states...trying to find a way to have three states (on constant, on ignition, off), and a way where the coil only has to be energized as needed, not all the time.

...unless I'm misreading your diagram...

 

The coil would be engaged when the switch is on, but not when the ign power is on. If you used a center off dual pole dual throw switch, you could wire a 2nd relay to turn off the ign power. I use relays all the time, they are built for it and the coil doesn't draw much for amperage, so I wouldn't worry about having a relay on whenever the circuit is engaged. It is still better then diodes. Not only do they get hot, but there is a voltage loss across them, so there is still wasted power.