Blue Sea fuse block ignition hot?

[offroad_nomad]

I dug around here a bit, but couldn't find anything on point.

What would be the safest way to make a Blue Sea fuse block ignition hot? Could someone provide some directions? I have zero wiring experience and will most likely turn to a buddy to assist me.

In my mind I can see wiring the fuse block to the battery with either a fuse or circuit breaker between them and a relay to an ignition hot fuse in the stock fuse block. Where I'm getting confused is that I've seen posts with "heavy gauge" wiring going from a battery to an aux. fuse block. But if I want to place an ignition hot relay in between, do you run the "heavy gauge" wire from the relay to the Blue Sea block carrying the power? Not sure if I'm making sense.

My intention is to power my 3 pairs of Hella 550s, a pair of Piaa 520s, VHF radios, aux. 12v power outlets and leave room for expansion.

Any assistance is appreciated.

 

[Mlachica]

I think the safest way to do it is to use a solenoid that's rated to the maximum current draw of all your accessories together. And you would use wire suitable to this same current rating from the battery to the solenoid and from the solenoid to the fuse block.

IMHO a safer, easier approach would be to have a constant hot fuse block and wire the control switches in series from an ignition hot 12v source. This way your switch can only activate the relay when the ignition is hot. This method is good for your lights. Your radio is best wired directly to your battery to avoid any interference. You'll just have to remember to turn off your vhf radio when not in use. Also, it's nice to have constant hot 12v accessory outlets.

 

[adventureduo]

My Blue Seas block is wired hot all the time. Never a problem. Some things are always hot like, cigarette plugs, radios, gps. Things that i may want to use while the truck is off. Other things are only work when the ignition is on like Mark said, stuff like my lighting, trailer brakes etc. Generally things that draw more power.

 

[4RunAmok]

Yup, heavy duty relay rated to the sum of your plugged in accessories. Or a solenoid if you're pluggin in serious stuff.

In my (not yet implemented) design, I have a hot and a switched Blue Sea. Either one each, or take apart one to see if I can have both on one fuse block.

Odd that you'd ask this, I was just thinking about this on the way to work this morning.

 

[Mike S]

For your project, calculate the amperage load (watts divided by volts) on each load leg and the total load through the fuse block. Plan wire gauge based on load and run. Fuse the runs at the fuse block. The power to the block is total of all amperage loads supplied by the block. Plan a good ground for the block load. Use good wire, ring terminals, solder or crimp and heat shrink tube the connections.

Relays are good for some things, but usually not super high amperage. For that use a continuous duty solenoid. I expect that your load would be 30 amps or less, so a relay and main fuse (or better yet a circuit breaker) that slightly exceeds total load will do the job. Some loads (motors) will spike on start up and exceed their rated load spec, so figure that into the calculation.

 

[4RunAmok]

Yep, in my setup, between the battery and the fuse blocks will be these:

You can get them here:
http://www.powerwerx.com/fuse-holders-fuses/

In fact there are a LOT of great items for doing your electrical system properly on that site.

 

[Mlachica]

My intention is to power my 3 pairs of Hella 550s, a pair of Piaa 520s, VHF radios, aux. 12v power outlets and leave room for expansion.

6 hella 550's 55watts each
2 piaa 520's 85watts each

6 x 55watts = 330watts / 12volts = 27.5amps
2 x 85watts = 170watts / 12volts = 14.17amps

total load (amps) from lights only = 27.5 + 14.17 = 41.67 amps

add the vhf radio and any expansion and you're looking at a small solenoid to be able to handle the current flow. In addition to the individual relays to control your lights.

It may be inconvenient to you since you already have the blue sea fuse block but may I suggest this fuse block...(I have one on the way in addition to two blue sea 12 circuit fuse blocks)
http://www.sleeoffroad.com/technical/tz_interior_fusebox.htm

Can be purchased from Slee or www.wranglernw.com +/- 30 bucks.

It's a dual feed block, one power source feeds 9 circuits, a seperate power source feeds 3 circuits. You can find an ignition hot circuit and use it to control a relay to feed the 3 circuits. And use a constant hot circuit to feed the other 9 circuits. Then use an ignition hot circuit from the fuse block to power the switches to activate your lights via relays, with your lights directly fed from the 9 circuit side of the block. In other words your lights are fed from the 9 circuit side but controlled from the 3 circuit ignition hot side.

I hope this wasn't too confusing.

 

[offroad_nomad]

I think I may have found what I've been looking for, 3 constant hot and 4 ignition hot circuits:

Painless Wiring Cirkit Boss Auxiliary Fuse Block

 

[offroad_nomad]

Option 2

Running with Mark's suggestions of using a solenoid, I was thinking that this might work too. I'm going to need some help here:

1. Wire a 12V Continuous Duty Solenoid 200 amp to the battery.

2. Protect above with a Bussman Surface Mount circuit breakers manual 150 amp (or similar breaker).

3. Wire solenoid to a 12 Circuit with Negative Bus Blue Sea Fuse Box.

Question: How do I get power to the solenoid to open/close its switch when key is turned to "ACC" or Ignition thus sending current to the fuse box?

 

[adrenaline503]

My Blue Seas block is wired hot all the time. Never a problem. Some things are always hot like, cigarette plugs, radios, gps. Things that i may want to use while the truck is off. Other things are only work when the ignition is on like Mark said, stuff like my lighting, trailer brakes etc. Generally things that draw more power.

I plan on wiring mine to constant hot. I suppose you would have to be more careful to keep thing turned off, but I have never killed a battery before anyway.

 

[jbs]

Option 2

Running with Mark's suggestions of using a solenoid, I was thinking that this might work too. I'm going to need some help here:

1. Wire a 12V Continuous Duty Solenoid 200 amp to the battery.

2. Protect above with a Bussman Surface Mount circuit breakers manual 150 amp (or similar breaker).

3. Wire solenoid to a 12 Circuit with Negative Bus Blue Sea Fuse Box.

Question: How do I get power to the solenoid to open/close its switch when key is turned to "ACC" or Ignition thus sending current to the fuse box?

This is what I did. For the ACC signal, I just used a meter to check all the empty spots in my stock fuse box and found one that was only on with ignition. I have lots of empty spots though b/c I have a base model 4Runner. Alternatively, many 12V sockets are on with ignition only. You could tap into one of these.