Electrical questions...what works best?

Sometime this weekend, or maybe the next, I'm gonna be replacing/rewiring my headlights and battery. I'm going to be following the instructions from projectxj.com for making a new wiring harness for the headlights (switching from sealed to Hella composites with Hella Optilux H4 Xenon White XB 100/80w bulbs) and switching to an Optima battery. I've seen people running the red top, and the yellow top. For those that have them, what works best for handling moderate load pull (I.E.- lights mentioned above, fog lights, soon to have pair of hella off-road lights, and sound system with amp, sub, etc.)??? Is there a big difference between the two? I'm hoping 5-90 will chime in on this next part since I've heard he has welding cable for battery wires. Does this help with anything? I know they offer little to no resistance as far as electrical flow goes, but will it be enough to be noticeable and/or effect anything? Basically, is it worth doing? Thanks in advance to anyone that's still reading. Any help is greatly appreciated!!

I've recently been told that installing my battery cables made for brighter headlights - something told me that his OEM cables were farther gone than originally thought...

I use 1 gage since it's good for about 250A for any run under 50' - and the longest we've got to look at it about 14' bumper to bumper.

As far as battery selection, I'm running Optima Red Tops backed up by 140A alternators - and I'll probably keep it that way until I get around to relocating the starting battery and adding the two deep cycles (blue top?) that I've got in mind - but I'm also planning on rerouting most of my lighting to go right to the secondary batteries, ditto the stereo and sub/amp, and some auxiliary two-way radios I haven't installed yet. I won't be using a solid-state isolator - they cost too much and I can do the job cheaper, better, and more reliably using a 100% DC solenoid.

Unless you are planning on running a lot of electrical stuff without your engine going at the time, a red top will serve nicely - the reserve capacity and Ah ratings are quite enough unless you are going to get silly. Save the deep-cycle idea for if/when you are going to run significant loads without the engine running and the alternator going - but it would be a good idea to upgrade your alternator and your mains cabling (and if you can't find a good rewind shop, mine is willing to do mail orders. I can give you contact information if you'd like - he's in San Jose, CA.)

For electrical loads - especially high-current electrical loads - there is no harm whatever in using a wire that is several sizes too large (and some good can come of it.) The larger cross-section presents a lower effective resistance, and therefore less drain in the circuit before the power gets to the consumer. Also, the fine strands of the welding cable that I use both make the cable more flexible (and therefore easier to handly) but also effective larger than a "battery" cable of the same composite gage (resulting in a higher ampacity.) Welding cable has about 150% the current-carrying capacity than a coarse-stranded battery cable of the same nominal gage.

I selected one gage cable as an effective compromise between shipping weight, cost, and overkill - you just don't need anything larger unles you're running several alternators, or a multi-kW generator under the hood. I honestly believe you're not going to use the full capacity of 1 gage wire with common equipment - including an average winch (and if you want to go larger than what's generally available, you're better off with fluid power or a PTO anyhow.)

If you have a lot of trouble rigging a headlight harness, let me know. I've been getting requests to see what I can do about costs on that little project, and if I feel like there are enough people interested, I'll do some digging and see what I can do. People seem to be happy with my battery cables (especially for the money you pay for them!) and I'm always willing to help fellow Jeepers save a few bucks...

5-90

Thanks for the great info....I sent you a PM with further questions, etc.

red top under the hood there are 2 sizes a less cranking amp one and a 800cca go with the bigger one and if you want more juice hook up a 2nd battery a yellow top not blue because blue is for marine use yellow is industrial.

Most "marine" batteries are "semi-deep cycle" - they're designed to handle the LARGE load from cranking (can be up to 400A or so!) and not prematurely discharge from a sustained low-current load (that's the deep cycle part.)

The "industrial" is probably a "pure" deep cycle, meaning it's designed for nothing but a sustained low-current load (anywhere from, say, two to fifty amps,) and repeated high-drain cycling (starting an engine) will cause premature failure.

When I do my "three-battery" setup, I'm planning on retaining the Red Top, and adding two Blue Tops - which will give me a backup starting reserve in case the Red Top goes silly. That's why I'll install a bypass switch on the solenoid I use as an alternator...

Naturally, get the most power you can fit into the space - the system will only draw what it wants, and the additional capacity simply makes for a longer reserve...

5-90

firehazzard said:

red top under the hood there are 2 sizes a less cranking amp one and a 800cca go with the bigger one and if you want more juice hook up a 2nd battery a yellow top not blue because blue is for marine use yellow is industrial.

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The yellow top and the blue top are identical inside. I checked with Optima before putting in my blue top. The only difference is the blue has extra screw terminals.
And I used 2/0 welding cable to make my battery and starter cables with soldered lugs and heat shrink. I know. Waaaay overkill. But what the heck. I had an opportunity to get some 2/0 real cheap.

K

Yeah - I've got 2/0 cables in my 87, but that cable was left over from a rewiring job (GPU's at the airport) and it was already paid for - along with the terminals and tools.

I eventually settled on 1 gage for two reasons - 1) it's already big overkill, 2) anything bigger just costs too damn much to ship.

Since 1 gage is good for about 250A at 50 feet, I don't think it CAN be overloaded in an automotive application - unless your alternator is stamped "Leece-Neville" or is two feet across...

5-90

Instead of starting a whole new thread, I figured I'd just post up on this again since it is loosely related to my original questions. I was looking through the article on Gojeep.com (www.go.jeep-xj.info/HowtoHeadlightLoom.htm) on how to make your own headlight harness. I understand all of it except for one part. Where is the stock headlight switch that they keep talking about wirn g stuff to???? The length they give for the switch wires isn't long enough to run all the way to the dash switch, so where is it?

Dvipercop said:

Instead of starting a whole new thread, I figured I'd just post up on this again since it is loosely related to my original questions. I was looking through the article on Gojeep.com (www.go.jeep-xj.info/HowtoHeadlightLoom.htm) on how to make your own headlight harness. I understand all of it except for one part. Where is the stock headlight switch that they keep talking about wirn g stuff to???? The length they give for the switch wires isn't long enough to run all the way to the dash switch, so where is it?

Click to expand...

I think what he means is that you plug the new homemade harness into one of the original sockets that goes to the headlamp. That would still be controlled by the original switch in the dash and supply power to the new relay instead of the existing headlamp.

K

If you want check out Jason West's write up on his site... www.jeepin.com. He installed the IPF headlight upgrade with a new harness and relay set up... I would suggest it to anyone thats going to upgrade the lights or else you risk the chance of burning up the factory harness and possible vechicle FIRE.