Jeep JK Dual Battery Kits To Keep Your Jeep Starting in the Boonies
If you spend a lot of time on trails or in the backcountry, dual batteries are your friend.
The extra capacity can be put to good use for winching, refrigerating, emergency starting, and the other high draw loads that happen when you're in your Jeep, miles from anywhere.
But man, is this electrical stuff hard!!
It seems like you need a degree to figure out how to put together a dual battery setup - mounting, isolation, wiring, and all that stuff. Not fun.
In this article, we'll take a look at some of the easy ways you can install dual batteries in your JK.
The Most Complete Dual Battery Kit for Jeep Jks
It's bolt-in, prewired, and you can use your existing battery cables. The isolator is fully automatic - it charges intelligently, isolates to ensure that you have enough juice to charge, and you should never need to think about it unless you use the "boost" button for self-jumping.
If you want to get fancy, you can monitor the system with the Genesis G Screen Dual Battery Monitoring System.
Why Do You Need Dual Batteries?
There are a few use cases we see for using dual batteries. Basically, if you need extra electricity or redundancy, you should hook up dual batteries.
Starting Redundancy for Your Jeep
Clearly, if you're out in the boonies and you run your battery down, you're screwed.
Your Jeep JK's battery has one job: To start your engine.
If it can't do that, you're either hiking out or stuck waiting for someone that can give you a jump. This situation can either be a mild inconvenience on a well-traveled route, or dangerous if you're far from roads in bad weather.
With a dual battery setup, you just flick a switch to "hook up" your other battery and start your Jeep. No hiking. No waiting. No worrying.
We do a lot of solo trips at Roundforge, and we know that lots of other people do too. There is something nice about going at your own pace and exploring what you want when you want to do it.
Dual batteries give you peace of mind that you can be far from civilization, but still be able to come back!
Winching Your JK
It's well-known that if you winch your Jeep a lot, you want dual batteries. Batteries have a certain amount of capacity and winching can quickly drain a battery.
Remember that in starting your Jeep, your starter only runs for a a few seconds. But your winch may have to run for several minutes! (Tip: Keep your winch cool by letting it rest!)
If your battery is a glass of water:
- Your starter motor takes a sip of water.
- Your winch guzzles the water.
Many a single-battery Jeeper has found out that their Jeep won't start after an extended winching session due to a dead battery that wasn't replenished long enough by the alternator.
Dual batteries mean you can winch longer and harder without worrying.
12 Volt Fridges
While starting redundancy and winching are about safety, an extra battery also provides you with more comfort and ability.
We've camped for years with a cooler that needed ice - usually a sloppy mess by the end of the first day. But a 12 volt fridge can immediately change how you expedition.
Suddenly you can keep meat, fruit, and veggies properly refrigerated indefinitely - it makes a huge difference in camp each night.
However, you don't want to be running that fridge on a single battery:
- It runs all the time
- It uses a lot of electricity
If you leave your Jeep for a while with the fridge going, you might come back and find out that your battery is dead!
An isolated second battery fixes this.
Lights, Pumps, Electronics - OH MY!
The second battery in a dual battery setup can also be hooked up to provide you with other in-camp comforts without worrying about your starting battery. These are things like:
- Extra cabin lights
- Inverters for running laptops
- Water pumps for onboard showers
- Off road lights
Basically, having a dual battery setup in your JK can give you some creature comforts without worrying about whether your Jeep will start after you've watched a whole season of "Housewives of Atlanta" in the rooftop tent.
Which Batteries For a Dual Battery Setup in My Jeep?
If you need lots of detail, we talk a little about different Optima batteries here, plus the differences between deep cycle and starting batteries. If you want the best of the best, we'd go with two deep cycle Group 34 Odysseys. They have a higher CCA rating than Optimas and an excellent reputation.
If for some reason you want a dual post battery, you should look at a Group 34/78 battery like the Optima YellowTop D34/78. These batteries have two top posts and two side posts.
However, we think you're better off using positive and negative bus bars for power distribution, rather than relying on the dual side posts.
For starting redundancy
Get 2 starting batteries that are the same brand, model, and age.
You can get standard starting batteries from the local auto parts store - generally, these should be a Group 34 - that's the battery size that most battery trays are made for.
Want something more robust? Get an Optima RedTop in the Group 34 size.
For starting redundancy plus winches, refrigerators, or loads that can draw down your battery
Get 2 deep cycle batteries that are the same brand, model, and age.
Deep cycle batteries handle can handle deep discharges regularly without getting wrecked like a starting battery.
These batteries should be the Group 34 size. We'd recommend either an Optima YellowTop D34 or an Odyssey 34-PC1500T. The Optima is a very well-known upgrade, but the Odyssey is both well-regarded and has higher cold-cranking amps.
What's the Basic Dual Battery Setup in a JK?
Here's the deal:
You basically have two choices here: buy a full kit, or piece something together by yourself.
If you want to bolt in, plugin, and go, you can do that.
If you want to piece together a system and tinker, you can do that, too. We'll show you a few of the parts you can use if you want a DIY battery setup.
We'll warn you, though, that several of the commercial tray-only Jeep JK kits are made in China and have pretty poor fit and finish.
A basic dual battery setup for your Jeep JK will include:
- A bolt-in dual battery tray: In JKs, these trays are setup to fit the batteries side-by-side. They are not stacked or end-to-end.
- An isolator/solenoid: The setups for isolation range from super dumb (you decide how to charge/discharge with a manual switch) to super smart (electronics decide how to charge/discharge). We recommend a smarter setup
- Wiring: Obviously, you need more battery cables and wiring for the isolator/solenoid, and any accessories you want to add.
Full Dual Battery Kits
Genesis Offroad Jeep JK Dual Battery Kit with 200 AMP Isolator
If you want a bolt-in kit, buy this one.
It has everything!
Genesis clearly put a lot of thought into this kit and it's the top-selling dual battery setup for Jeep JKs on Amazon.
This is a bolt-in, plug-in dual battery kit. No fuss, no muss. And it does exactly what you want it to:
- Charges both batteries when necessary.
- Isolates the "starting" battery and preserves starting juice when you're using a lot of electricity
- Provides a "boost" mode to jump your starting battery from your secondary battery
- Includes pre-cut and pre-terminated cables and wires
- Provisioned for a battery status monitor
- Places to hook up power and ground for any accessories
- Easily pop out your batteries since the isolator and wiring are integrated into the battery tray clamp
It comes with:
- A dual battery tray: It fits two Group 34 batteries side by side up against the passenger side firewall
- A 200 amp smart isolator: You don't need to even think about the dual batteries unless you use the jumpstarting "boost" mode
- Pre-cut and pre-terminated cables and wires: This probably eliminates about half a day of figuring if you do this on your own
- An extension cable for the evap solenoid: On '07-'11 JKs
And to top it all off, it's made in the USA!Basically, if you want it all in the perfect package, this is the Jeep JK dual battery kit that you want.
Jeep JK Dual Battery Trays and Isolators - FOR DIY DUAL BATTERIES
Some of these trays are "bolt-in" but many of the reports we've seen say that they really aren't. You may have to do some filing/drilling/grinding to make some of these kits fit your Jeep.
If you want a custom tray setup you can see dual battery tray setups here. Those trays will involve making your own brackets, but you might decide that's preferable to working with one of these battery trays.
Rugged Ridge Jeep JK Dual Battery Tray
The Rugged Ridge Tray will fit two Group 34 batteries side by side against the passenger side firewall. These trays come in black powdercoat and include hardware. We're not a big fan of this tray for a few reasons.
First, the installation isn't the greatest - many users report that the installation is difficult to do and difficult to figure out because the instructions are just terrible. This tray doesn't actually use a metal clamp - it uses straps!
Sure, this probably works okay.
But frankly, we'd rather have the set-it-and-forget-it of standard metal clamps.
Lastly, this setup mounts the batteries left to right. The Genesis kit mounts them front and back. With the Genesis kit, you can reuse your original Jeep battery cables, but it's a little more difficult with the Rugged Ridge dual tray setup.
Of course, once you have this tray installed, you still need to figure out your wiring and isolation setup.
Rugged Ridge Tray 2007-2011 JKs
Rugged Ridge Tray 2012 JKs
Smittybilt Jeep JK Dual Battery Tray ('07-'11 only)
Like the Rugged Ridge tray, this isn't the best Wrangler dual battery arrangement we've seen. Again, the batteries are placed left and right, not front to back. This can make it more difficult to retain your stock battery cables.
Also, Smittybilt strangley says that this tray is only for Optimas. Some trays have the problem that the top clamp is specifically designed for Optimas, but this one is really just a piece of angle with holes drilled in it.
You should be able to use any battery in it that you want.
We'd prefer this tray to the Rugged Ridge, mostly because it use does not use a strap to hold the battery down.
It's probably the most budget of the budget trays and would be our pick if you need a cheap, bolt-in dual battery tray for your Wrangler.
KeyLine Dual Battery Isolator
Want to DIY your dual battery setup in your Jeep? This is a little trickier, since you need to figure out how to wire things and also terminate all the connections yourself.
However, if you don't mind spending a few hours putting things together, you can definitely save some cash with a DIY setup.
One component you'll need is a smart isolator. The isolator determines which and how your batteries should be charged. It also ensures that you'll always have enough capacity left to start your Jeep.
Isolators work by sensing voltage and "flipping the switch". So, once your primary battery drops to a pre-determined voltage, the isolator cuts it off so that it won't be used any further.
This isolator from Keyline is rated for 140 amps. It smartly charges both battteries when they need charging. It cuts in at 13.3V and cuts out at 12.8V to preserve the charge in your starting battery, meaning that you should alway have enough juice for starting.
Blue Sea Systems HD Battery Switch
If you want a robust, this is a solution that boaters have used for years. Effectively, a battery switch is manual isolation. Instead of circuitry deciding whether to charge your batteries or whether to isolate one of them in the setup, you decide to do it.
There are different ways to set this up, but you would generally want a switch that supports running off battery 1, running off battery 2, and running off battery 1+2.
Let's say you want to take this setup Jeep camping:
On the drive to your camp, your selector is at "1+2", charging both batteries. At camp, you want to run a 12V fridge and some lights, so you switch to "2" to run only off battery 2. When you finally leave, you switch to "1" to use battery 1 to start up - it's still fresh since it wasn't used at camp. Once started, you switch back to "1+2" to charge them both.
A switch is a lot more mental work to run, but they are the cheapest way to get dual batteries in your JK with the benefits of isolation.
Last updated: Jun 2019