Electric Gurus! Two way switch questions!

[midnitewarya]

Hey all,

Wiring in some off road lights. I'll have lights on the bumper, roof, rear and rock lights. I do a lot of stuff out in the sand dunes at Glamis/Pismo, and out there you can never get enough lights.

My question... I have a on/off/on switch. I also have a bank of four switches. Each of the four powers a relay to each of my four zones. I'd like to wire the on/off/on to power everything on at once in the first on position. The second on position would power the switch bank, allowing me to chose what I want to power. Would I need a bank of relays for each of the on positions, or could I share the relays? I'm worried about back current burning something out or bleeding to the other accessories.

No exact reason to do it, I just like switches and think it would be neat to have a one touch all on button.

Thanks in advance!

 

[6872xtc]

My thought says that you could do it that way as long as you install diodes to separate signal power when in the "individual select" side.

 

[Blue85]

Sounds easy. Just use diodes. Only 1 relay required per device.

The 2nd on of the master switch will power ALL of the individual switches. Then each individual switch powers a relay. That's straightforward. The 1st on of the master switch will power the relays through diodes. That is, one diode per relay. That engages everything no matter what position the secondary switches are in. Without diodes, they would all come on together all the time, whenever any of the switches is engaged.

Now if all of the switches were on-off-on, that would give you another option. Each item could be ON, OFF or MASTER and no diodes required - even using relays would be optional.

 

[midnitewarya]

Diodes you say? I've heard of them, but have never played around with them. I'm assuming they come rated for certain voltage and amperage? Are they made for auto installations or more on the electronic side.

I'm intrigued for sure, I'm excited to get to assembly.

 

[6872xtc]

This is knid of info is where Blue85 does awesome work! You need correct volt/amp rating, plus proper install.

 

[midnitewarya]

I've started digging trying to educate myself on the use of Diodes. I've got the theory of it down, however I'm stuck on application. It seems there is an auto specific type of diode, made for 12v DC systems. I even found some info on Diodes that look like blade fuses, which would be awesome, cause all I would need is a fuse block to do the install. Most of the other Diodes I'm seeing are simple pieces of wire. Having a hard time wrapping my kind around reliably installing something like that.

 

[bronc3buster842001]

The blade style diodes are easy to find... Just hit the local junk yard and look at the 96 up model trucks... That style diode was in the fuse box for the A/C system..

 

[wasted wages]

Make it easy for ya.....

diode = electric check valve..... lets current flow only one direction.

simple as that.


Oh, and they have a marking on them to let you know which way the current flows.

Pick one up at radio shack,,, find a 1156 light bulb and a few jumper wires and a 12 volt power source...
will be easy to figure it out...

 

[midnitewarya]

Things are moving along with this. Had a quick question about the diodes and amperage. My relays are rated at 5amp at the switch. The most popular blade diodes are rated at one amp. I forsee blowing my diodes out. If I drop the voltage down to 1 (or 3 b/c I have found some 3), will my relays stick kick on at a voltage that is safe for the diodes? One amp just doesn't seem like enough juice to kick on four relays.

 

[Blue85]

What part of the relay is rated for 5A? That's WAY high for the coil, but pretty low for the contacts. I would think some of your accessories draw more than 5A. The diode will only power the relay coil - the current of your accessory is irrelevant (this is sort of the point of relays). Most automotive relay coils are well below 1A, so it would be strange if a 1A diode wasn't fine. Can you post a part number for the relay?

As for "drop the voltage down", I don't know what you mean - maybe reducing current through the coil to protect the diode? Like I said above, it's probably not necessary. An automotive relay probably needs around 9V to pull in, but you will have available the battery voltage, probably minus 1V or so.


The attached is what I what proposing. This is for 4 devices, but obviously it can be scaled to any number.

 

[midnitewarya]

What part of the relay is rated for 5A? That's WAY high for the coil, but pretty low for the contacts. I would think some of your accessories draw more than 5A. The diode will only power the relay coil - the current of your accessory is irrelevant (this is sort of the point of relays). Most automotive relay coils are well below 1A, so it would be strange if a 1A diode wasn't fine. Can you post a part number for the relay?

As for "drop the voltage down", I don't know what you mean - maybe reducing current through the coil to protect the diode? Like I said above, it's probably not necessary. An automotive relay probably needs around 9V to pull in, but you will have available the battery voltage, probably minus 1V or so.


The attached is what I what proposing. This is for 4 devices, but obviously it can be scaled to any number.

Hey Blue, thanks for the diagram, that's exactly how I have it sketched out, less the fancy symbols...

Here are the components that I'm using so far:

On/Off/On - http://www.k-four.net/Product.aspx?pid=273
On/Off - http://www.k-four.net/Product.aspx?pid=272#
Relay - http://www.k-four.net/Product.aspx?pid=102
Blade Style Diode - http://www.waytekwire.com/item/46880/1-AMP-MINI-FUSE-DIODE/
Fuse Blocks (One for Diodes) - http://www.k-four.net/Product.aspx?pid=98
Wire Harness for output to acc. (x4)- http://www.ebay.com/itm/2-Pin-Quick...-volt-12in-SAE-connectors-Solar-/261381149000

Still deciding on what kind of box to put all the hardware in. I have the switch box figured out, but for the relays/fuses/diodes I'm thinking of modifying a Pelican case or something similar. All outputs will be male/female connector harness, so I won't have to worry about wiring in the box once it is installed. All grounding will come from the box and wire directly to the accessories, this way I'm not drilling a million ground screws into my truck.

Thanks for the help!

 

[Blue85]

That all looks good.

One idea to consider is to get an electrical center from some car in a junkyard - one with relays and fuses already in it. Then you just rewire it all from the bottom to suit your needs. It's likely that many of the relays will already be tied into a buss bar. I got one from a Ranger or something - it had like 6 relays in it, slots for mini fuses and maxi fuses and already had a couple of those diodes.

Also, be wary of pre-wired fuse sockets. The cheaper ones have terrible crimps that will fail. A 40A relay is no good if the socket melts at 20A. I like to back the terminals out and solder the core crimps before using them. (Factory electrical centers, on the other hand will use proper validated crimp procedures).

 

[midnitewarya]

That's some good info on the fuse blocks. I'll definitely go through the ones that I purchased. I'd grab some junkers, but the closest yard to me is about a 100 miles, so the trip kinda kills it.

So you think the diodes that I picked will be fine? That's awesome.

I'll keep this thread updated as the build comes along.

Thanks again.

 

[AR_K5]

Wow talk about over complicating things.

Two simple options are get a heavy duty master switch to power all of your other switches, then you can keep the accessory switches on and just kill the power to everything all at once or turn the master on a select what you want.

They also make control boxes to do exactly that. Look in places where they sell police/fire lights and such. I had one hooked to a full size multi function light bar, and it worked great.

Here are some links that should help.
http://www.galls.com/galls-nine-fun...tch?PMSRCE=20920030&SESSIONID=000000063457532

http://www.galls.com/galls-six-function-switch-box?PMSRCE=20920030&SESSIONID=000000063457532

http://www.chiefsupply.com/search/?q=Switch+box

Also check eBay.
Good luck!

 

[midnitewarya]

Wow talk about over complicating things.

Two simple options are get a heavy duty master switch to power all of your other switches, then you can keep the accessory switches on and just kill the power to everything all at once or turn the master on a select what you want.

They also make control boxes to do exactly that. Look in places where they sell police/fire lights and such. I had one hooked to a full size multi function light bar, and it worked great.

Here are some links that should help.
http://www.galls.com/galls-nine-fun...tch?PMSRCE=20920030&SESSIONID=000000063457532

http://www.galls.com/galls-six-function-switch-box?PMSRCE=20920030&SESSIONID=000000063457532

http://www.chiefsupply.com/search/?q=Switch+box

Also check eBay.
Good luck!

I thought of that, that was actually my first choice, but they get very expensive fast. My goal was to mount the solenoids in the engine compartment, that way I would only have to bring a single harness through the firewall. With the law enforcement stuff, wiring is everywhere. If you do use a relay box, it gets mounted inside with the switch box. If you don't use the relay box you have to juice all the power through the switches, which is something I don't want to do.

What I'm building is something similar to the SPOD for the JK Jeeps.
http://www.4x4spod.com/

 

[AR_K5]

Another recommendation if you are worried about amp draw would be to upgrade to a 1000 cranking amp battery, add a power cap like those used for hight wattage stereo amplifiers in cars (essentially a small battery), or add a second battery to power your accessories.

This should help you understand
Volts = pressure
Amp = volume
Watts = units
Amps x Volts = Watts
Watts/amps=volts
Watts/volts=amps
1 amp @ 1 volt = 1 watt

So to figure how big of a fuse you need for 5 lights rated at 100w each would be calculated like this: 500(w)/12(v)=41.66(a)
Therefore you would want a 50a fuse between your master switch and your battery and (if you are really anal about it) 10 amp fuses between each switch and light. That is considering each switch controls 1-100w light.

Of course you would want to use a volt meter to get your actual voltage at the light.

*in order to keep it simple I skipped over Ohms (resistance), but this should give you a basic understanding.

 

[AR_K5]

I thought of that, that was actually my first choice, but they get very expensive fast. My goal was to mount the solenoids in the engine compartment, that way I would only have to bring a single harness through the firewall. With the law enforcement stuff, wiring is everywhere. If you do use a relay box, it gets mounted inside with the switch box. If you don't use the relay box you have to juice all the power through the switches, which is something I don't want to do.

What I'm building is something similar to the SPOD for the JK Jeeps.
http://www.4x4spod.com/

Ebay - 300 amp master switch - $6.52 with shipping
http://bit.ly/KVHIMz

 

[AR_K5]

What exactly is your reasoning for with using relays, and what type are you trying to use?

I just don't understand why you want all the extra connections. Every added connection just creates more resistance (more amp draw) and more places for problems to develop. Just use fuses and heavy enough wire to handle the load without heating.

I'd run 10 gauge (or bigger) wire with an inline 50-60a fuse from your battery to the master switch, then 12-14g wire to everything else.

The Galls 6 way switch box already has built in fuses on each switch.
Read the descriptions.

As far as wires go, loom them together with tape, zip ties, heat shrink tubing, or that plastic stuff with a slit down the side, and hide the wires.

Keep it Simple!

 

[midnitewarya]

This is why I use relays...

This JKU had a switch setup similar to the galls setup. Fire started behind the dash. Problem with running accessories without relays is all the heat and amperage you have to run in through the firewall, and through the switches. All it takes is some exposure and rubbing and the heat can become a serious problem.

That's why every single auto manufacturer uses relays for high draw accessories. My switch box will be very low amperage, with all the high amperage located in a fuse block. Relays are also the best way to run high draw accessories, you can place the relay closer to the thing you want to power than you can the switch.

Most of the Galls and Whelen switches you are talking about usually end up getting hooked to something like this:
http://www.galls.com/galls-90-watt-remote-power-supply

That way with this you run low amperage through the console and fuse replacement is easier. Ever blown a fuse on a Whelen without a remote power supply? Got to disassemble the center console and those ridiculous safety torx to get to it. When you blow one with the remote power, you reach behind the seat and pop the fuse out.

 

[AR_K5]

The only reasons it would have heated up is if:
A: there was a short and no fuse
B: the wires were too thin to handle the load
C: the wires were not properly connected.
Aka: human error

They probably used little bitty wires connected with electrical tape on some devise that draws a lot of current. For example putting power to 4-KC lights with 20g speaker wire will result in melted wires and fire.

I've wired everything from competition grade stereo systems, to remote control airplanes, and never once have I had to add relays.

IMO
The reason auto manufactures use them is to allow them to save weight and money by using smaller wires, thus smaller looms of wires running throughout the vehicle.

I think you are being a bit paranoid, but hey, it's your rig, not mine, do what ever you want. I was just giving my 2¢ Trying to help, but it sounds like you've got it under control. Good luck.