12v ingnition ON Source

I have a handy looking power/fuse box which is supplied directly with battery power for things I want to run with ignition off. It looks like so:

I have both 12v and ground available from battery.

My question is, where can I get enough 12v ignition ON power source for another box to power accesories, lights etc. Electrical wizards please chime in.

 

I are no wizard. But I used my multimeter to find a circuit in the fuse box that was only on with ignition, used an add a fuse for a little current, then used that as the signal for a relay for moar current.

Like I said though. I'm just a hack, no wizard.

 

Use a relay that you can turn on with with a switched source and feed the fuse panel through that from the battery

 

This is the correct answer.

Just connect an add a fuse to any switched source such as the power point or radio fuses to power the small relay.

Switched Source >>> Add A Fuse >>> Relay Coil >>> Ground.

Battery >>>>>>>>>>>>>>>>>>>> Relay Contact >>> Your Added Fusebox.

 

Don't forget the fuse between the battery and the relay contact.

And use term 87 for the battery side. If you use term 30, then 87a is hot when the relay is turned off

 

It seems my hack job is actually the proper way, although these guys explained it a little better.

But yes, use a fuse or a breaker between battery and relay for sure. And make sure your relay can handle whatever current you want to put through it.

 

I look at it this way. He is adding in a fuse panel for multiple things he adds on. I really see no need to fuse a fuse panel because each load of the fuse panel will itself be fused.

1.) Battery >>> Fuse >>> Relay Contact>>> Fuse Panel >>> Multiple Individual Fuses >>> Multiple loads

Or

2.) Battery >>> Relay Contact >>> Fuse Panel >>> Multiple Individual Fuses >>> Multiple Loads

Make sense? I like # 2. I see no reason to fuse a fuse panel.

 

You fuse the wire feeding the fuse panel because it is unprotected. Fuses aren't there to protect the things they're feeding. They're there to protect the wires from burning up! Make sense?

 

What your saying seems to make logical sense. But I would still recommend a fuse. I just tried to type out my reasoning but it didn't read very well and I'm pressed for time, so I'll leave it at "I've been told by professionals that it's best practice"

 

Put a circuit breaker between the battery and fuse panel, itll protect the fuse panel and its easier to reset vs replacing a fuse.

 

The ACC fuse in the kick panel fuse box to the left of the steering wheels is
12v switched

 

Yes it makes sense as in I understand what you are saying. I've been an electrician and electronics technician for greater than 40 years....

How about that piece of wire between the battery and the fuse? It could go on and on... At what point do you stop fusing a wire?

My point is there is no load on that wire until it is connected at the fuse panel. And each of those loads will have its own fuse. That being said it doesn't hurt to add one and neither way is wrong. You will just have to ensure the wire feeding the panel can handle the full load of the panel and then fuse it according to the full load of the devices that are added.



Not my truck, not my issue.

 

The only way a fuse between the battery and the relay would do it's job, is if a wire before the fuseblock rubbed through and shorted to ground. Route your wires carefully and protect them from sharp edges. Look at it this way. You already have a VERY large unprotected wire going from the battery to the starter, going right past surfaces that could melt the insulation very easily. Even if you install the above mentioned fuse/ circuit breaker, you still have an unprotected section of wire between the battery and fuse/ circuit breaker.

 

Winch main power wires are unfused also.

 

Keep the wire feeding the fuse as short as practical because it is unprotected. There's no load, that's true. However, for the sake of argument, imagine running the feed through the firewall to the fuse box and it gets nicked and is now a direct short. Not a pretty picture...

Also, for those that don't know, rule of thumb, 120 watts at 12 volts is 10 amps of current.

If this was my project, I would feed the fuse panel for what it's rated for.

@Muddinfun, that wire is oversized to begin with and the insulation is rated for the temps it encounters

Btw, I am an electrician.

 

Mine is on a big breaker.

 

I guess the issue here is where the OP intends to mount this fusebox. I just assumed it was going to be within a foot of the battery. If it is going to be mounted anywhere past the firewall, I would definitely install a main fuse or fuseable link wire.

 

Yeah, mine is also. Well, not a breaker, but fused. I have a disconnect for the main winch wire, and when the disconnect is on, my main battery wire is fused. I only fused it because the run from my battery, in the bed, is so long to the engine bay.

The stock battery main 12v wires are not fused.

 

It will be mounted near the main battery. This is good info. So what I'm reading is fuse the wire that's directly feeing the panel? And or the 12v supplied wire for the relay as well?

 

Everything I run is protected from the point it receives power. That's the safest way and the only "legal" way in the field.