Electrical Help Needed

[scott slade]

Hello,  My 05 TJ Unlimited is used as a camera vehicle on various television and commercial shoots.   I need to install a remote fuse block to power some of the add on's, like a power inverter and extra 12 volt outlets. I already have police style strobes running from a splice in the cig lighter,but don't like that.  Is there a pre-made kit to run a fuse block off the battery..? I need about six fuse points.   Should I think about dual batteries..??   Can anyone offer some help with this.  Installing a stereo and speakers seems easy...  this bigger power demand is kind of scary... need to do it right. So any advice would be great... Thanks....

[4PLAYZJ]

F.Y.I.  If you are wiring strobes yourself be careful the capacitors in the system can deliver 50,000volts +, next to no amperage but it will give you one hell of a jolt.  Also make sure that the strobes do not alternate, if they do you are breaking the law.

[BlackAura]

I haven't tried to do this myself, however I have read about other people's electrical installs, and have a friend who ran a second fuse box in his truck.  (In other words, confirm everything I'm writing with someone else first, and don't hold me to it)

My buddy went to the wreckers and grabbed a Ford Ranger fuse box, which he installed under the dash (of his Ford Ranger), and then ran the appropriate cables from there to his additional devices (additional in-cab lighting, a power inverter, and box lighting).

Some basic info on choosing fuses, which gauge wire, and how to wire everything (somewhat technical, sorry):
[spoiler]You have to remember that the fuse you choose for each device in the fuse box is based on the wire you're running to the device.  The wire you choose is based on the power requirements.  For example if you know something pulls 24W off 12V DC, you can calculate the amperage:

(P is the power in watts, V is the voltage, I is the current in amps)

Thinking back to high school algebra:

We can take P = IV, and rewrite it as:

P / V = I

So 24W / 12V = I

I = 2 amps.

Then you find a site which has a cable size calculator, to determine which gauge wire you need.  In this case, I assumed a 6 foot run with 5% loss (I'm just going by their recommended values), and 75 degree insulation, and wound up with 18 AWG.  Honestly, I would just punch in 5 amps, so you can fuse it for that.  Turns out 5 amps is also 18 AWG.  Going higher gives you a bit of breathing room in case your device overloads the circuit slightly for a short time (when it's first starting up).


Now, when wiring the actual fuse box, say you've got 5 x 5 amp fuses, and 2 x 10 amp fuse.  With that you could theoretically pull 45 amps with your secondary fuse box (someone correct me if I'm wrong, but I'm pretty sure the additive property applies).

Lets say you have an 8-foot wire from your battery to your secondary fuse box.  You can find ANL fuses for 100amps pretty easily, I believe.  (giving you room to install more fuses as required)

Plugging in 8 feet and 100amps into the calculator above shows 4AWG.  Proper install techniques would be to run a very short lead from the battery to the ANL fuse (i.e. 6 inches or so), that way the remaining 7.5 feet going to your secondary fuse box, would be safely fused, in case it shorts out along the way for some reason.
[/spoiler]

Other things to think about:

Is your alternator able to handle the additional load on the system?  If not, you may want to look into upgrading it.  As long as your alternator can handle everything you ask it to, there's no reason to get a second battery, unless you intend to run some of your electronics with the engine off.


If you plan on running switches for some of these electronics, make sure you setup relays, rather than putting the switches inline in the circuit....at least for heavy-load devices.  Or find a switch that can handle the amperage you plan on putting through it.

[Tinkerer]

All very good pointers.

From the Ham community, who run tons of moderate current toys, I'd suggest a RigRunner.  The reason I suggest it is multiple in your application:

• It provides warning if the voltage is too low or too high before it trashes expensive electronics.
• It cuts power before the battery is dead or you fry the expensive electronics.
• It has an overall fuse and individual fuses to protect each device
• It has easily plugged and un-plugged connectors that are standard for Ham equipment and some industry, but not so much for anyone else.

http://www.westmountainradio.com/product_info.php?products_id=rr_4008_c



They can be bought locally at NTF communications up by Barlow Truck Stop, possibly from the CB shop in Road King or online from various vendors such as http://www.radioworld.ca.

Edit: I wired mine straight to the battery through a circuit breaker, the recommended way to do it.

[murray195]

  BlackAura is on the Ball!
And that would have made things a little cleaner on my project Tinkerer  lol
I figured I'd throw in my $0.02:
Back on the family farm in Manitoba, I had '81 Chev 1/2ton that was primarily used as a farm workhorse. I was running I had a cb radio, multiple spotlights, power inverter and a small winch for pulling stuff out of the bush. For the lights,and cb,  I had one 8 gauge stereo wire running from the battery to a re-settable circuit breaker. From the fire wall mounted circuit breaker, I ran 8 gauge into the cab to a power distribution box. I got stereo system fuse holders which happen to be mountable and accept the LARGE rectangle fuses. These wires with fuses coming from my power distribution box supplied the constant 12V  input for the accessory relays.

I used 3 pin KC switches as above. I connected all the "PIN 86" to the accessory wire for my ignition so I didn't accidentally leave something on. I put all my grounds together into a crimp and shrink eye-lit connector and used a self tapper screw to secure the ground network to the body under the dash.

This kind of gives you an idea and is by no means a complete explanation for everything that had to be done. The power inverter had its own circuit breaker and had a stereo capacitor in-line.

[scott slade]

Thanks Guys...  that unit you suggested Tinkerer looks like just what I need.  Good point about the alternator and the switches. I am sure the switches that come with any product are rated for the unit.  With something like the Rig Runner I feel I can do the job myself... will try and find one this week.   In regards to the strobes Playzj....  they are used in a controlled traffic situation (non police colors) such as the last Iron Man here and in Penticton...   Local police who attend such shoots think it was so much better than a cheap revolving roof light.  So all is good there.  but yes something like that could be abused.   What are the options on a higher output alternator..? 

[4PLAYZJ]

The highway traffic act states that only emergency vehicles can have alternating warning lights, color does not matter.  I work for a utility as a tech and we have to sink all of the strobes we install or our guys can be given a ticket.

[yyc_tbird_sc]

Hmmm...alternating lights....just gotta be sure you're permitted for it 

I'm going to have to add some circuits here soon to my new truck, and I will be picking up a Blue Sea Systems fuse block. They come in either 6 or 12 circuit versions, and even have the ground block in place. I'd look into something like this for simplistic installs.

[scott slade]

Thanks for the tip on the Blue Sea System.... Anything easy and safe is what I need... I did not realize what was out there....  Have to do some research on the alternator... any thoughts on a dual battery...?  thanks....     

[Tinkerer]

Hmmm...alternating lights....just gotta be sure you're permitted for it 

Yep, they changed things since the last time I looked: http://www.canlii.org/en/ab/laws/regu/alta-reg-122-2009/latest/alta-reg-122-2009.html It's a new regulation with some twists, but in general, more permissive. One definite exception to the alternating lights is school buses, they are *mandatory* unless a municipal regulation says otherwise, which is why they tend not to have them in the city, but they do in the country.

[BlackAura]

I did not realize what was out there

Nor did I, some of these fuse block setups are awesome.  Will make my electrical plan for the TJ much easier!  Thanks for asking the original question Scott!

Have to do some research on the alternator... any thoughts on a dual battery...?  thanks....

As I said, regarding the dual battery, in my experience most people run it so if their accessories drain the "main" battery, they always have the starting battery charged and ready.

So it really depends on how you plan on using your electronics.  If you'll be running them with the engine off for long periods of time, I would recommend looking into it.

If you'll always have someone there to jump you, maybe it doesn't matter. (although replacing dead / non-recoverable batteries could end up costing more than the dual setup)

If you'll always have the engine running, and your alternator can handle it, it's probably not worth the extra cost to you (in my opinion at least).

[Vinman]

http://performanceparts.com/part.php?partID=23129

I've used these in 3 different vehicles with great results.
Best part is they're weather resistant and you have the choice of switched and/or constant power.
Vince