<%@LANGUAGE="VBSCRIPT"%> ROCKCRAWLER.com - Kilby Enterprises Dual Battery Tray


By Bill "Willie G" Snowden

Send this article to a friend!

Kilby Dual Battery Tray
Kilby Dual Battery Tray
Everyone knows the excellent reputation of the products developed by Kilby Enterprises and available at 4x4rockshop.com, as well as direct from Kilby and other retailers. Unfortunately, I had never had quite gotten around to purchasing anything from them for any of my Jeeps because I traded vehicles so frequently. So, when I was offered the chance to test an early production version of his new dual battery tray for TJ’s with air conditioning, I jumped at it.

Dual battery setups have not been offered for TJ’s with the 4.0L engine and A/C until now because the return side of the system places the accumulator right next to the stock battery tray and limits the room available for two batteries. The Kilby dual battery setup comes with a new A/C line designed to move the accumulator closer to the engine and free up that much needed room. You can use this line or discard it and have an A/C shop fabricate one to suit your needs if you need a more custom setup. Either way, you will need to take your Jeep to an A/C shop to have the lines evacuated and refilled once you replace the A/C line.

The box arrived from Kilby Enterprises at the shop of Staff Writer, Tony Lopez in Brighton, Colorado and he and I eagerly tore into it as if it was Christmas morning! We verified that the parts were all there and admired the thick, 3/16” black powder coated steel tray with its milled hold-down bar and KILBY logo. Truly a work of art and very stout, which considering that each Optima battery is 43 pounds, it needs to be!

Tony quickly placed a phone call to his friends at Total Car Care, just a few blocks down the street. Their master A/C technician, Eric Welch, was intrigued by the idea of seeing a ’03 Rubicon up close, as well as the Kilby dual battery setup.

Eric examined the new A/C line furnished with the Kilby kit, hooked up his Robinair service unit, and evacuated the system in short order. Eric then removed the old line, and after coating the o-rings with refrigeration oil, installed the new Kilby line in its place.

The bracket that supported the accumulator was flipped over and reattached to the accumulator and to the firewall. It all fit perfectly. Eric recharged the system, checked for leaks, and pronounced the Rubicon fit for summer. The whole operation took 35 minutes and $75.

Kilby Dual Battery Tray
A/C Lines Before
Kilby Dual Battery Tray
Kilby line being held in place to show location.

Then it was back to the shop to install the tray and two new Optima batteries. Removal of the old battery and tray was accomplished quickly. Following the instructions, the new tray, with the accumulator out of the way, went in just as easily.

[NOTE: If you have ever experienced problems with water in the passenger floorboard when running the A/C during the summer, you know that the underhood airflow can sometimes force the water back up the drain hose, which causes the problem. I took this opportunity to install a ½” plastic elbow into the drain hose. I filed down the ridges on one end and it slid into the hose easily. I did this now, because the drain hose will be much harder to reach with the dual battery tray in place.]

The instructions suggested that the PDC (Power Distribution Center) be moved forward to ease the installation of the batteries. On my Rubicon, the second battery installed easily enough, so I didn’t move the PDC. Yours may be different, due to manufacturing variances at the Jeep factory.

Kilby Dual Battery Tray
Tray shown installed, after installing the new A/C line.
Kilby Dual Battery Tray
Notice that the battery temperature sensor is reused.

With both batteries in position and the hold-down bar in place, all that remained was to wire the batteries. There are several ways to wire your dual batteries. Painless Wiring makes a dual battery wiring harness that includes the option of switching between Battery A, Battery B, or both. Or, you can choose to use an electronic isolator from one of several manufacturers which will allow you to divide your vehicle’s electrical load between the two batteries, while at the same time, making sure that both are kept fully charged by the alternator.

Kilby Dual Battery Tray
Tray with batteries installed.
Kilby Dual Battery Tray
Tray with batteries installed.

A third option, which I chose, was to simply wire both batteries together in parallel – positive to positive, negative to negative. Though you lose any sort of battery management, this method is the least expensive, and gives you double the cranking power and double the reserve capacity. The only absolute requirement is that both batteries be the same (identical) capacity and age. You cannot mix and match or the weaker battery will drain the stronger and could cause both to fail.

Tony and I built two new battery cables to link the batteries - each one about 7 ½” long and 2/0 guage. We soldered the terminals (use rosin core solder, not acid core) and used heat shrink tubing to seal the job.

Kilby Dual Battery Tray
Completed Installation with wire jumpers
I chose to reuse the original OEM battery cables and combined them with two of the new battery terminals supplied with the kit. You’ll notice from the pictures that I placed the positive cable exactly where it had been on the original - close to the PDC. The negative cable was cut loose from the factory loom and placed over next to the firewall and the accumulator. My thinking, totally unsupported by any scientific knowledge, was that this positioning would force the two batteries to act as one, with the current unable to take a shortcut through just one battery – just as your radiator hoses are placed at opposite corners of the radiator to avoid the water failing to flow through the entire radiator.

So, how does it work? Well, after a hard day of winching myself and others, I had no starting problems and noticed no unusual alternator activity. Most importantly, I had complete peace of mind that I wouldn’t be stranded with dead batteries.

Currently, there are no other dual battery kits on the market that allow the use of dual Optima batteries. If these are your battery of choice, then I would highly recommend the Kilby dual battery setup for any TJ with A/C and expected heavy electrical loads, such as lights, stereo, winching, etc.

Kilby Enterprises
1847 N. Keystone St.
Burbank, Ca. 91504
Phone: 818-848-2900


Help spread the ROCKCRAWLER world!           Share on Facebook

©1997-2022 ROCKCRAWLER 4x4 and Off-Road Magazine. All Rights Reserved.

RockCrawler.com   -   IH8MUD.com