Update -- This modification was done prior to my S2K Build-Up, at which time I removed the Cole Hersee switches and replaced them with three ARB switches to control my York compressor and two air lockers.  I've since removed the ashtray and installed a second 3-switch bezel, which houses the three Cole Hersee lighted rockers switches.  One of the switches, plus a new double-pole double-throw (DPDT) momentary toggle switch that I added, controls my winch from inside the cab; click here for the write-up on my winch page.

For more information about the Cole Hersee line of electrical switches and other related products, visit their web site at www.colehersee.com

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I was looking at my fuse block (behind the glove box) the other day. This is what I saw. What a mess! No less than 5 wires, from various accessories, jammed into several fuse openings. You know . . . remove the fuse, insert the wire, and mash the fuse back into the hole. Works great! But I have no idea how many amps these various electrical accessories draw and what the impact is on my vehicle's electrical system. To tell the truth, I don't even know which wires go to which accessories! Therefore, I decided to purchase a Painless Wiring Weatherproof Circuit Isolator (auxiliary fuse block). It has 3 "hot" circuits and 4 "ignition-switched" circuits. Installation is pretty straight forward. First, find a location to mount the isolator and the main fuse. I mounted mine next to the under-the-hood fuse/relay box on the passenger side fender well. Feed the pink wire through the firewall and connect it to an ignition-switched circuit. You get a little fuse adapter thingie with the kit, but I used the tried and true insert-the-wire-and-mash-the-fuse-back-in-the-hole method. Cut the huge 10-gauge red wire to length, crimp on the supplied connector, and attach it to one of the terminals on the 30-amp main fuse (also provided with the kit). Using the remaining 10-gauge wire to connect the other terminal on the main fuse to the battery. And that's about all there is to it.

Here are a couple of shots of the isolator. In the picture on the left, the weatherproof cover is installed. The small square part on the right side of the isolator is a relay, which is replaceable if it ever burns out. Just in front of the stock auxiliary fuse block, is the 30-amp main fuse that comes with the isolator. After making the connections to the fuse, I sealed them with some "liquid" electrical tape. In the photo on the right, the weatherproof cover is removed. Note the larger size fuses as compared to the mini fuses used in the main fuse block behind the glove box.

               

The next step is to reconnect all those wires that are currently plugged into various fuses behind the glove box (or otherwise spliced somewhere into the vehicle's wiring harness), to the 7 new circuits provided by the circuit isolator. Here's what my Jeep's main fuse block looks like now!  The pink wire that's still connected is the one that powers the ignition-switched circuits on the new isolator. BTW, if any of your electrical accessories contain an in-line fuse, I highly recommend not removing that fuse. Each of the fuses in the circuit isolator is rated at 20 amps, whereas your in-line fuses are likely rated much lower. Therefore, the 20-amp fuse in the isolator is rated way too high to adequately protect many of your lower-rated electrical accessories. Speaking of fuses, the only thing that I don't like about the circuit isolator is that it uses the larger size fuses instead of the mini fuses that are in the main fuse block. Now I have to carry extras of both sizes.

After connecting all of my accessories to the isolator, I made up a little laminated card, which fits under the fuse cover, to identify what's connected to each circuit. The circuit isolator basically returns your vehicle's electrical system back to stock condition. All of my accessories are now powered by dedicated 20-amp circuits and are totally isolated from the vehicle's electrical circuitry. 

For more information about the Painless Wiring Circuit Isolator and other related products, visit their web site at www.painlesswiring.com

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Well, it was just a matter of time before my original factory battery went Tango Uniform.  Nearly five years I got out of it . . . and it didn't live an easy live, either!  I had drained it down several times, either from winching or running electrical devices off of my inverter.  I think that's pretty impressive.  So when it finally died, I decided to replace it with a complimentary pair of Optimas.  Having previously read several articles about dual batteries, I knew exactly what I wanted: a Red Top to power my starter, and a Yellow Top for everything else.  But I wasn't sure exactly how I wanted to "manage" the two batteries.  After researching various options, I finally decided on a simple, good 'ole multi-battery isolator . . . forget all the fancy switches, lights, and relays.   I picked up a heavy-duty (for use with up to a 120-amp alternator) Sure Power Isolator (Model #1202-D) from Pep Boys for $49.  At the same time, I also wanted to upgrade all of the battery cables.  So I purchased 25 feet each of red and black 1-gauge cable (not cheap at $1.40 per foot!), and a handful of matching lugs.  Finally, the batteries.  Also not cheap: $160 for the Yellow Top and $130 for the Red.

My first challenge was to position each of the batteries.  A couple of companies manufacture dual battery trays for TJs (without A/C).  Trust me, if you have a 4.0L TJ with A/C, a York compressor, and a 2.5-gallon air tank all stuffed under your hood, you ain't gettin' no second battery in there!  Although I hated to sacrifice the storage space, I decided to locate the starting battery in my "trunk".  I build a wooden tray out of plywood and secured it to the tub with a few sheet metal screws.  Then I secured the battery to the tray with some wood screws.  I built a cover for the battery, with a slot in the side for the cables.  Finally, I drilled a pair of holes in the tub and ran the cables through some grommets, forward along the frame rail, and into the engine compartment.  

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Under the hood, I installed the deep cycle battery in the stock battery location.  Next I fashioned a bracket to securely mount the isolator.  After removing all of the old wiring, I cut the new 1-gauge cable to length and soldered the heavy-duty lugs to each end.   From here, it was just a matter of connecting everything together.  This was the easy part.  The isolator only has 3 posts, "1",  "A", and "2".  Connect from the positive terminal of one battery to post "1" and the positive terminal of the second battery to post "2".  The positive terminal on the alternator goes to post "A" on the isolator.  The negative terminals of both batteries and the alternator, all connect to the engine.  Next I ran a jumper from the Yellow Top's positive terminal to the vehicle's main fuse box, and a jumper from the Red Top's positive terminal (from the #2 post on the isolator, actually) to the starter.  Finally, I reconnected the positive and negative winch cables to the Yellow Top's positive and negative terminals, respectively.  To the right is a closer view of the battery isolator.

Click here for a schematic diagram of the system

Management of the two batteries is totally automatic.  As I understand it, the isolator contains some diodes, which allow the alternator to simultaneously charge both batteries (while the engine is running, of course), yet totally isolate the power flowing from each of the batteries to their respective systems.  That means I can "winch and invert" off of my Yellow Top to my heart's content, and still be able to start up the engine with my Red Top!

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As I stated in my Dual Optima Batteries write-up above,  "Trust me, if you have a 4.0L TJ with A/C, a York compressor, and a 2.5-gallon air tank all stuffed under your hood, you ain't gettin' no second battery in there! " 

Well, Mean Green (known for their gear reduction starters and high output alternators), went and made a liar out of me!  They've come up with a dual battery tray, that will accommodate 2 Optima batteries (mounted on their sides) under the hood of a 4.0L TJ with A/C!  Amazing!  Installation is a simple bolt-in.  Start by removing the battery and the factory battery tray.  You will also have to disconnect and remove the battery temperature sensor from the factory battery tray.  At first, I didn't know why Mean Green didn't make accommodations for the battery temp sensor in their dual battery tray.  So I simply welded in a small piece of 3/4" x 1/8" steel in one of the corners, and shoved in the sensor.  The instructions that came with the battery tray stated that failure to reconnect the sensor may cause the Check Engine Light to come on.  And we wouldn't want THAT to happen!  Later I found out that all you have to do is "reconnect" it, not "reinstall" it.  It will suffice just to zip tie it off to some other wires in the engine compartment, just to keep it out of the way.  It supposedly doesn't even work with gel cell batteries, like the Optima. 

The lower Mean Green tray installs using the existing holes in the engine compartment (as shown above).  Carefully lower the first battery (on its side) into the tray, with the terminals facing towards the front of the vehicle.  Connect the lower battery at this time, cuz once the second one is placed on top, it's impossible to access the terminals on the lower one!  I connected the batteries the same way as I did originally, when the Red Top was located in the trunk.  I simply pulled the wires out from the rear, re-cut them to length, and soldered new lugs to them.  The negative terminal on the Red Top battery is grounded to the engine block.  The positive terminal goes to Post #2 on the battery isolator, and then to the starter. 

Next, install the upper battery tray and the two sections of all-thread rods (as shown above).  Secure the lower battery and the upper tray using two of the nuts provided (but don't over tighten).  Place the second battery in the upper tray and install and secure the top strap.  Again, over tightening may damage the battery case, so use care.  Note: you might have to reposition the PCM box forward just a bit in order to fit the second battery.  Mine fit, but just barely, so I moved the box forward anyway, about a inch.  The negative terminal of the Yellow Top battery is grounded to the engine block.  And the positive terminal runs to Post #1 on the battery isolator, as well as to the vehicle's main fuse box.  The finished product is shown to the left.  It's a super clean installation and frees up that precious space in my trunk that I've been missing for the past year.

For more information about the Mean Green Dual Battery Tray, as well as their gear reduction starters and high output alternators, visit their web site at www.mean-green.com

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