How to Install Onboard Air and an Auxiliary Battery in Your Jeep Wrangler JL
American Adventure Lab has a smart and seamless solution for adding OBA and auxiliary power to your Jeep.
Jeep's Wrangler JLs are electrically complicated vehicles. From the two factory batteries under the hood to all of the sensors that run the CAN bus system, these rigs are incredibly sensitive to unapproved loads and curious voltage drops. Because of this, Jeep offers four auxiliary switches to easily access the vehicle's electrical power without upsetting all of the modules and data flowing across the vehicle. But what do you do if you need more ways to power up accessories and require more onboard capacity to extend time between engine starts?
A dual battery kit seems like the best option, but most people don't realize that the Wrangler JL already has two batteries under the hood. The main battery is a traditional Group 48 size AGM battery with 65 Ah of capacity used for cranking, and there is a smaller 12 Ah supplemental AGM battery used to power everything else (when Electronic Start Stop ESS is active at a stoplight, for example). The system also uses an Intelligent Battery Sensor (IBS) and variable-voltage alternator.
There is a popular dual battery conversion system on the market, but there is disagreement amongst some enthusiasts about the strategy of its operation, and if the instructions for which battery to connect the IBS sensor is optimal for the setup. It also requires a new battery tray and two smaller Group 25 59-Ah batteries (we will stick with Odyssesy's number throughout this story to be as apples-to-apples as possible) to replace the stock units, which might be a red flag for some owners with Wranglers still under warranty. Another issue is with an error code from the Electronic Start Stop system that triggers because the system expects to see a voltage differential during cranking between the two batteries when they disconnect. Obviously if you are using one battery in this scenario, you can't have a voltage differential and the JL flags it. It will automatically clear after six ESS events (per start), or it can be turned off manually via the switch on the dash (each start).
So, with those things in mind, we went looking for a solution that would give us additional battery capacity to run our accessories in the backcountry, but without going to a true dual system or modifying the factory battery setup or operation. What we found was an innovative setup being offered by American Adventure Lab out of Washington, Utah, that answered all of our concerns. It mounts an Odyssey PC1100 AGM Powersports battery in the rear underfloor storage area on a bracket that can also support ARB's exceptional CKMTA12 twin-motor high-performance air compressor.
The PC1100 auxiliary battery itself has 45 Ah of capacity (enough to run our Dometic CFX3 45 fridge for about two days in ideal conditions) and, when combined with the 65 Ah of the factory cranking battery, gives us 114 Ah of total power. The popular dual battery system that uses two Odyssey Group 25 batteries has a total of 118 Ah, making this a comparable alternate solution. Something else to consider is that an easily removed tab in the Wrangler JL's battery tray allows for fitment of a Group 94 battery, which offers 80 Ah with the Odyssey platform. When upgrading to an Odyssey Group 94 and using the PC1100 with AAL's kit, the total rating jumps to 125 Ah.
Controlling the charging function is REDARC's BCDC1225D dual-input 25A charge controller. This is a 12V DC-DC battery charger that is designed to charge an auxiliary battery to 100 percent capacity while on the move and also allows for solar input, which it will prioritize if both inputs are active. It's a smart controller that can be set up for compatibility with a variable-voltage alternator, making it a perfect fit for the Wrangler JL. A multi-stage charging algorithm provides specific charging profiles for all common battery types, including AGM, gel, standard lead acid, calcium, and even LiFePO4 batteries. The Australian-made REDARC has been designed to be tough and rugged. It can withstand extreme heat, up to 176 F, is fully sealed against dust and water, and can handle battery banks with up to 200 Ah.
Circling back to the ARB CKMTA12 air compressor, it is perfectly at home on the AAL mounting bracket. This is one of our all-time favorite compressors, and at 6.16 cfm, it has the highest compressor output rating that we've seen. The CKMTA12 has enough output to run most air tools without a tank, inflates tires quickly, is sealed from moisture and dust (IP55 rating), and has a 100 percent duty cycle. It's constructed of lightweight, high-strength materials and utilizes Teflon-impregnated carbon-fiber piston seals, hard anodized cylinder bores for reduced friction, and a brushless fan for cooling. To keep things safe, the CKMTA12 incorporates an over-pressure safety valve, thermal protection, and fuses for each motor.
American Adventure Lab also offers an optional remote bracket that is designed to make this setup more user friendly. In addition to housing the compressor switch, breathers, and air chuck out of the way, the AAL remote kit adds a 12V plug for your fridge and a six-way ATC fuse block with a negative bus. This allows you to hook up six additional electrical circuits in the back of the Jeep that work off the auxiliary battery. Having 45 Ah of additional capacity to run your fridge and other electronics means one to two days of additional power without having to start the vehicle. Supplementing this system with solar can extend that by days, depending on the panel setup you choose.
The beauty of this setup is that it gives you comparable dual battery capacity without modifying anything under the hood, keeping your Jeep looking stock. In fact, only two wires touch the JL's factory electrical system. One is the power wire from the REDARC to the cranking battery, and one is a trigger wire to a keyed ignition wire (we used the ignition wire in the auxiliary switch bundle) that tells the REDARC you have a variable alternator. Of course, there is also a chassis ground. Everything else about this setup is completely self-contained, safely maintaining the integrity of your factory electrical system without introducing any mysterious draws or voltage drops.
Are you still you intrigued like we were intrigued? If so, read on to see how we completed the install on our manual AEV JL370 3.6L, and head over to American Adventure Lab (americanadventurelab.com) for more information on how to get your hands on a setup like this for your Jeep Wrangler JL, and soon JK.
American Adventure Lab
American Expedition Vehicles
American Expedition VehiclesWixom, MI
Baja RackSan Diego, CA
Odyssey BatteryReading, PA