If you are into off-road adventures, you know that you need power for your portable electronics to enhance self-sufficiency and functionality while traveling. Therefore, having a dead battery is a major inconvenience and even dangerous in some situations. Fortunately, installing a second battery in your vehicle will prevent the risk of losing power to your gear while in the backcountry.
There are different ways to hook up a second battery in your vehicle. However, with the right tools, you’ll need to wire the second battery in parallel with the original battery. Then you’ll have to install a solenoid or relay to isolate the batteries depending on whether you’re driving or parked.
Researching dual battery system setups can be quite confusing. Therefore, we have explained all you need to know about setting up a second battery on your Isuzu MU-X.
What is a dual battery system?
The dual battery setup is a battery system that connects a secondary battery to a vehicle’s starter battery. The second battery acts as a power source for auxiliary gear and accessories. This system ensures your vehicle has enough start-up power and your campsite and gear have consistent power, too, without the risk of draining your vehicle’s starter battery.
How does the dual battery system work?
The second(auxiliary) battery is connected to the vehicle’s main battery in a dual-battery system. The alternator also charges both batteries while you’re driving, but the two batteries function as two isolated systems. This means your vehicle’s main battery and alternator power the car and its electronics while the engine runs.
On the other hand, the second battery powers all the other camp-based devices, such as lights, portable fridges, and radios, when you stop your car and turn off the ignition. You can also use the auxiliary battery to jump-start the starter battery.
You connect the two batteries in parallel (positive to positive and negative or negative) through a relay. The relay connects to an ignition switch and senses voltage to connect the batteries when the engine is running.
So, when you turn off the ignition, the relay isolates the batteries so that the starter battery does not get drained when you are powering your campsite gear off the auxiliary battery.
Who needs a dual-battery system?
A dual battery system is vital to anyone who wants their car to run a heavy electrical load without worrying about draining their starter battery.
Anyone who does off-the-grid camping often will need a dual battery system for their vehicle. In addition, you’ll need the auxiliary battery to power your campsite accessories, such as a camping fridge, lights, inverters, and other essential equipment you’ll need while in remote areas without compromising your vehicle’s power source.
The dual battery system is also worthwhile if you plan a long-distance drive. Should your starter battery suddenly drop in voltage, the auxiliary battery will help jump start, preventing you from getting stuck.
Another reason to hook up a second battery is if you want to operate a heavy-duty electrical device, such as an electrical winch, that draws a large amount of power.
People with a high-performance audio systems can also benefit from a dual battery system in their car.
What parts do I need for a dual-battery system?
You need several things besides an additional battery to have a functional dual-battery setup in your vehicle. Fortunately, several dual-battery system kits have everything you need for a DIY install. Here are all the components you need for a dual battery system:
- Deep cycle battery: These types of batteries can handle the constant discharge and recharge cycle than standard engine cranking batteries.
- Battery isolator: This allows your vehicle’s alternator to charge both the starting and auxiliary batteries independently. It also disconnects your starter battery from your auxiliary battery, allowing you to draw power from one battery at a time.
- Power inverter: Converts the DC power stored in the auxiliary battery to AC power for devices that don’t use DC power, such as kettles, hair dryers, and anything device with a wall plug.
- Heavy gauge DC wiring: You need correctly sized cables to pass current between devices in the dual battery system for safer use and operation of your electrical devices.
- Dual battery monitor: Allows the user to check voltage levels on both batteries by observing an in-cabin readout. It also helps maintain electronic control over the dual battery system.
- Fuses: Protect the system from electrical malfunctions.
- Voltage Sensitive Relay(VSR): A computer controller for both batteries.
How to install a dual battery system in your Isuzu MU-X
Usually, setting up a dual battery system in your vehicle involves professionals, but if you know your vehicle and several tools, you can install them yourself.
There are different dual-battery system setups, but the solenoid-based system is the most cost-effective and reliable way to install a dual-battery system. This setup involves a solenoid switch that engages when the engine is running and automatically disconnects when your switch off the engine.
Things you’ll need
- Dual battery kit
- Secondary battery
- Drill and drill bits
- Crimping tool
- Heat fun
- Wire cutters
- Diagonal pliers
Directions
Choose your installation location.
- The location of the second battery on your Isuzu MU-X could be in the engine bay or your car’s cabin. The location of the second battery will affect which type of chemistry you use.
- Also, choose a battery location where the battery, wiring, and other components are free from the elements. Finally, when you’re winter camping, keep the setup in temperatures between 41 and 113 degrees Fahrenheit for optimal use.
- Also, consider how far the wires will stretch to reduce voltage loss. You’ll need to keep them as short as possible.
Choose your battery
- Once you know where to put your auxiliary battery, you can choose the most suitable dual battery kit for your car, power needs and budget. For example, the wet cell lead-acid battery is great for an under-bonnet installation or on a Ute tray if there is sufficient ventilation to ensure no gas build-up during charging.
- Go for an AGM(Absorbed Glass Mat), Lithium, or GEL battery for fitment inside the vehicle or canopy. AGM and Lithium batteries are great for deep cycle use, long-lasting, and compact. In addition, cabin installs give you more freedom of space, and it doesn’t limit you to accessories and wiring that can withstand engine heat.
- Due to heat restrictions, we advise against mounting a lithium Isuzu MU-X battery replacement in the engine bay of your vehicle.
- Your choice of battery also depends on how much power you will need at your campsite.
Install the dual battery system
- Place your second battery in your car’s cabin and secure it on its tray.
- Disconnect the negative terminal from the Isuzu MU-X (original) battery replacement.
- Mount the Voltage Sensitive Relay (VSR) close to the starter battery and away from any hot or moving parts.
- Take the red cable with lugs on both ends and measure out enough length to run from the center of the VSR’s mounting place to the positive terminal of your starter battery.
- Cut cables to the correct length and do the same for the positive terminal of the auxiliary battery.
- Insert the lugs to the open ends of the cable by taking off about 15mm of insulation and crimping them in place. Place the heat shrink over the lug and apply heat for a waterproof seal.
- Take the black wire and attach it to the VSR to ground it. You can use a bolt to earth the engine or other engine components.
- Connect the starter battery to the VSR. The cable from the starter battery connects to the VSR terminal labeled with a red spot or “positive sense battery,” and the cable from the auxiliary battery goes to the terminal marked “positive second battery.”
- Take the black earth cable and connect it to an engine ground to earth the auxiliary battery.
- Attach the VSR to the mounting plate and connect the positive cables to both batteries.
- Attach the negative leads first to the starter battery and then to the second battery.
Test your dual-battery your system.
- Start the engine and use a multimeter to read the starter battery. When the voltage reaches 13.3 volts, you should hear the VSR click, and a red light illuminates to show the second battery is connected.
- Turn off your engine and measure the voltage from the main battery again. When the reading falls below 12.8 volts, the relay should disconnect.
Do you need a fuse for a dual battery system?
Yes, fuses act as safety valves in a dual-battery system. During a short circuit, fuses will burn out first, break the current flow, and protect the rest of the system. You will need the correct-sized fuses to help protect the cables from over-current.
Mounting oversized fuses will run the risk of burning out the circuit. Additionally, the fuses must be as close to the power source (alternator, battery) as possible to protect the full length of the wire.
When a fuse blows, it indicates a fault in the electrical circuit.
Best place to store your secondary battery in an Isuzu MU-X
The most suitable place to mount a second battery in an Isuzu MU-X is in the cabin at the back of the car. They have space in the engine bay for a second battery. However, more space is necessary for a large deep-cycle battery. Also, placing your secondary engine in the engine bay of your Isuzu MU-X will cover the fuel lines, making serving your vehicle more complicated.
The back of the car is clean, safe, well-ventilated, and away from the heat of the engine bay. This ensures your cables also last longer and prevent the occurrence of a fire due to overfilling the engine bay.
Conclusion
With a suitable dual battery kit, quality cable, proper circuit protection and wiring skills, you can hook up an auxiliary battery to your Isuzu MU-X. Installing an efficient dual battery system ensures you can stay off the grid as long as you like without the risk of running out of power. We hope this guide has helped you set up a dual battery system in your Isuzu MU-X, utilizing the back of your car, far from the elements.