So later on this month I will be installing 3 light bars on my bull bar. I have been trying to search for videos for installing a relay harness on side post batteries. So my question is where do the negative and positive wires from the harness go. I haven't messed with anything yet but I would like some feed back from you guys on what you think. I have been getting answers from buddy's of mine saying that there is adapters, and others saying get a battery that has both side and top posts.

 

So later on this month I will be installing 3 light bars on my bull bar. I have been trying to search for videos for installing a relay harness on side post batteries. So my question is where do the negative and positive wires from the harness go. I haven't messed with anything yet but I would like some feed back from you guys on what you think. I have been getting answers from buddy's of mine saying that there is adapters, and others saying get a battery that has both side and top posts.

 

There is a side post accessories adapter. You can find them at autozone/napa/orielly.
Best thing is to get a battery with a side post and top post. But if that is not an option, yes there is an adapter

 

I have more questions than answers.

What year, what model and trim level do you have?

What types of light bars are you looking at? LED types? or old school halogen auxiliary lights? What wattage or current rating?

Do you want a single switch to turn on all three light bars? Three separate switches, one for each bar? One switch for one bar and a second switch for the other two?

Is your goal to have a "factory installed" look to your wiring? Or do you want to show off the "big wiring harness" you have for your lights?

To answer about power supply points, I generally avoid the battery, no matter which way the posts are. Even with the caps and seals on modern battery terminals, corrosion is still an issue. Displacing or removing the covers and adding more nuts, bolts and ring lugs (all with different alloys) to the mix just makes everything corrode that much faster.

For "big wires" for old school halogen headlight relays or auxiliary light relays, I generally put a ring lug on one side of the inline fuse(s) and I prefer to attach that ring lug to the alternator "B+" output stud. If the starter power stud is more convenient, that one works almost as well, and for more modern vehicles with larger power panels or under hood fuse and relay boxes, the power stud on those is also a good point to tap.

For LED technology, and where I want a factory look, I use an "unused" position in the fuse block and wire from there. If there's an "unused" relay socket, I'll use that as well. High quality automotive or marine LED auxiliary lights should produce the same luminous output anywhere from 9V to 15V. These types of lights aren't as sensitive to voltage drop as halogen lights, and get no benefit from over-sized wires. You still need something adequate for the current load, but you don't have to go bigger than "adequate."

 

I have a 2001 LT 4X4 I have a 22 in Cree LED 140watt and 2 12inch 72watt also Cree LED. And I will have 2 relay harnesses one for the 22in and one for both the 12in bars. So you think it's better to use a fuse tapper in the fuse box than use from the battery. I also have 42in led light bar mounted on the roof but that one was wired to the fog light switch.

 

If I go in the fuse box, I populate the "spare" positions with new wiring. I don't use a "fuse tap," I put the proper lugs/pins into the fuse block frame, and I run my new harness out of the box behind the fuse block with the other stock wiring. That's when I'm going for a "stock" or "factory installed" look.

When more "add on" look is acceptable, or when over sized wiring is advantageous (relay harnesses for halogen "euro" headlights, for example), I go with one additional ring lug at the alternator "B+" output. That's the the big post where the charge wire to the battery attaches. If I need two 8 or 10 gauge fused wires, I twist those together and crimp and solder them onto a single ring lug so I'm only adding a single ring to the stack there. If the alternator isn't a convenient location (not really an issue on these vehicles), the starter post or the power post at the under-hood fuse block also works.

My experience is that anything I attach to a battery post causes my new wires, and everything else nearby to turn into strange colored powders and blow away. I just prefer not to deal with corrosion. Corrosion is a big enough issue with the stock battery connections, even with all the stock covers and seals intact.

Each of your circuits/harnesses will probably work from a 20 amp fuse and 12 gauge supply wire. I don't know if you have any "unused" or "spare" fuse positions in the under-hood fuse/relay block, and I've never tried to add new wiring to one of these trucks with the under-hood fuse/relay block, so I'm not sure how difficult it is. It sounds like you won't mind the more "add on" look, so that shouldn't be an issue for you.

 

I will admit that having a battery with side AND top posts opens up a lot more options and makes it a hell of a lot easier to add on anything electrical. I have a yellow top Optima in mine with both side and top posts, and the side posts are all factory wiring while on the top posts I have my amp, alternator big-3 wire, electric fans, and harnesses for my light bars hooked up.

 

^^^This^^^ is the best solution, however for someone who's not in need of a new battery you can always grab a ground almost anywhere and get your positive on the post where the lead from the battery connects at the fuse box under the hood.

 

yeah i always buy side and top post combination batteries. not even for accessories but ive had them crappy side posts strip out so you got another place to put the terminal.

you can try looking at auto stores, some sell terminals where you can attach a bunch of crap

 

Also, with side post batteries, if the battery terminal strips out just go to the hardware store and get a couple 1/4" bolts and a couple nuts, That is what I did, worked out great.