Dual batteries and electricity for accessories are important, especially if you have several accessories that need electricity to keep you on track.
This is part of our Land Rover Defender Series: Episode #4 Dual Batteries & Accessories Electric Connections.
How to become autonomous when traveling overland with your equipped 4wd?
What is the energy requirement in electricity that you need to consider for your vehicle?
Which electrical installation to have electricity?
This may depend on several factors:
- Do you travel in complete autonomy?
- Where do you stop overnight, do you plan camping on campsites or not?
- How long are your overnight stops, is it a one-night stop or for several days?
- How many equipments need electricity?
The solution to staying on track in every situation: Two batteries.
Whatever is your way of traveling, the first thing to do is to install a second battery.
Why install a second battery?
A second battery will allow you to use all of your accessories at night. It is to power various electrical accessories. This without fearing to discharge your main battery to the point of not being able to restart the next morning.
Pair & split dual batteries
It is absolutely important to have a good installation to pair and split those two batteries.
Relatively simple installations allow you to have a management of these two batteries quite effectively.
We are using for many years now IBS dual battery system. It was one of the most successful products at the time we needed it. It is also a Swiss product deemed to be reliable.
How does IBS dual battery system work?
IBS dual battery system is a big relay that allows pairing both batteries when the alternator works to recharge. The two batteries will thus recharge simultaneously. When the vehicle’s ignition is switched off, the relay then separates the batteries so that each battery can be used on its own.
An electronic box allows easy management with interesting functions. Such as being able to pair manually your batteries for a difficult cold start, and being able to protect the capacity of the main battery to a sufficient level to ensure a start even by unloading totally both batteries.
This electronic box also includes a display that shows the voltage of each battery, the charging voltage of your alternator when it operates, and the status of the batteries to know if they are paired or isolated.
The disadvantage of this system
They recommend using two batteries of the same type and capacity so that the charge levels are identical and do not end up wearing the batteries prematurely.
Our experience – step 1
This is what happened with our original main battery paired with an Optima Yellowtop 55Ah battery. Our main battery was a 110Ah dry type battery while our secondary battery was 55Ah AGM type.
The dry battery quickly lost capacity and no longer held the charge.
Our experience – step 2
So we bought a second Optima Yellowtop 55Ah to have two identical batteries.
AGM type batteries are interesting, they do not fear deep discharges and can be stored in several positions because they are waterproof and do not emit acidic liquid.
We are using this combination for many years now and are satisfied.
Many accessories are connected, such as the fridge, a 12volt portable ARB lamp, and a WAECO 12v/220v 550Watt inverter. We can easily power everything for one night stop, have light, and 220v to recharge our electronic devices.
However, we are a little disappointed with the capacity of the 55Ah Yellowtop batteries.
They are excellent batteries, but we think the small model has really insufficient capacity. Especially when considering installing other more energy-hungry accessories to use on the secondary battery.
Our experience – step 3
During our trip to Australia, my husband was inspired by various very interesting accessory settings.
He decided to install a fixed compressor, as well as a water tank with a pump. Of course, in addition to all the gear we already have connected to the secondary battery (the fridge, a radio VHF, UHF, HF, a CB, various work lights and lighting, and plugs).
It started to make a lot of accessories for our small electrical installation. So he decided to review everything from A to Z.
The batteries’ size choice
The main reason we chose 55Ah Optima Yellowtop batteries was the lack of space in the battery compartment.
In some SUVs like Toyotas, there is enough space under the hood to install two Optima 75Ah batteries. Which are already much more interesting at capacity level but are also much bigger in size.
In a Land Rover Defender, the battery compartment is under the driver’s seat and it isn’t very spacious. You don’t have many choices. You either have the place to put an original battery and an Optima 55Ah, either two Optima 55Ah. But this leaves little room for IBS system and other electrical cutouts.
The batteries’ places reviewed
So he decided to free up space by keeping the main battery under the seat and moving the secondary battery in the back. We have a “dead” space in our Aménagement 4×4 wood frame. This place accommodates ideally a much wider battery such as the 75Ah Optima Yellowtop. Room was also left to integrate the ARB compressor with a gallon of air.
After many measurements, my husband passed several meters of 35mm2 cable. From the battery compartment under the driver’s seat to the back of the trunk. This is where we centralized most accessories and the fuse boxes for those accessories. He carefully passed all these cables in protective sheaths under the chassis.
The problem with the second battery placement
The only thing he doesn’t like with this installation is the distance between battery 1 and battery 2. Indeed, when you pair two batteries with a coupler/isolator it is best to have both batteries equal of type and capacity but also that the wiring distance between the two shouldn’t be too long. The main reason is to not have too much loss from the alternator. This is why the alternator should be located close enough to the battery.
Compared to our first installation where the two batteries were next to each other, they are now separated by almost 2m50.
The solution for the second battery placement
He found the solution with an excellent Australian manufacturer during our last trip: REDARC.
Unfortunately, this brand isn’t easily available in Europe. It is a shame because they make excellent products!
The solution is to use a “charger” for the secondary battery.
The REDARC BCDC1240D is perfect for this use. Properly wired it allows you to keep your IBS dual battery system and to charge directly from your alternator batteries of all types: dry, AGM, or GEL.
This charger case is an additional electronic element. Something that doesn’t inspire confidence at first. Yet, it is intended to be placed in the engine compartment and doesn’t fear the elements or temperature differences.
We placed it in the cockpit, close to the auxiliary battery. This allows us to have an optimal charge of it.
What’s next for our electricity providing system?
For the moment we have kept the two Optima Yellowtop 55Ah because it is useless to change something that works. But the installation is ready for bigger batteries. As soon as the 55Ah will show signs of weaknesses, we will replace both of them at the same time. We now have enough space in the compartment under the seat and at the back of the trunk for two by Optima Yellowtop 75Ah.
In addition, with the REDARC BCDC1240D we will have the opportunity to connect a solar panel to recharge our batteries. We have not needed this option yet because we rarely make more than one night’s stops in the same place. But we strongly plan to buy a solar blanket of the same brand to become autonomous longer. Thanks to solar energy!
There we are!
I hope this post is helpful for you and that it leads you to choose the best dual batteries and accessories electric connections solutions for your use.
Would be absolutely pleased to hear from you! Reach out below to let us know your choices and your questions.
Check out our youtube video! It is part of the series dedicated to our Land Rover Defender equipment. You will clearly see our dual batteries and electrical gear installation.
Here are again the links to the manufacturers we’ve talked about:
Aménagement 4×4: crafting wooden interior layouts, OPTIMA Batteries: reliable deep-cycle batteries, REDARC Electronics: electronic voltage converters & associated products, IBS dual battery system: batteries’ manager & monitor
Talk to you soon & take care!