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Rockhound Installs Dual Batteries & IBS Relay in Our Old Ford

Posted in How To: Electrical on December 4, 2018
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We installed dual Odyssey batteries when we rewired our 1977 Ford F-150, Raymond, years ago thinking that was all we needed to power the 460 in our truck (“Wire Transfer,” Dec. 2014; The two batteries were placed under the expansive hood in aftermarket battery boxes and linked together to act as one huge battery. Years of hard use off-road, including a 2,300-mile road trip in Baja revealed that there was room for improvement (“Bajajaja,” Oct. 2017;

We brought the truck to Rockhound Off Road for some suspension work and said to owner Chris Sparks, “There’s an electric draw somewhere. Can you find it?” Sparks found more than a draw though. It turns out that one of our Odyssey battery had cracked after repeatedly pounding into a bolt protruding from the battery box.

This sent us back to the drawing board with a few new goals in mind. First, we wanted to set up our batteries so that they would be isolated, with one dedicated to starting the truck and the other available for winching and powering our fridge. But we also wanted to be able to link the batteries if the starting battery went dead. Slee Off Road is a premier Land Cruiser outfitter that we have worked with on past Toyota projects and knew exactly what we needed. Slee set us up with an Intelligent Battery System (IBS) dual battery relay.

These are the components that we used to relocate and rewire the batteries. In addition to the Odyssey batteries are an IBS dual battery relay, high-quality wire from EWCS, Painless Performance ClassicBraid, and terminals from Blue Sea.

The second goal of our battery rewiring was to transfer weight from the front of our truck rearward to provide a better ride over rough terrain. A 460 engine, a pipe bumper, and a huge Warn 16.5ti hanging off the front of the truck don’t exactly do it any favors, but moving 100 pounds of battery to the bed did help our weight balance. It also freed up space under the hood for us to add a cannister-style air cleaner that will do a better job of keeping our 460 engine healthy in the silt and sand we frequent.

Rockhound was able to fabricate custom parts and get the entire system installed in one long day, despite spending hours rerouting and terminating all of the wiring for the system. Even though Raymond has been “done” for the past year, whenever we use it on the trail we find more ways to improve its performance and functionality. This latest upgrade does exactly that.

Our previous setup used two Odyssey Group 78 batteries under the hood in aftermarket battery boxes. The boxes did not come with hardware, and the holes are not countersunk. We used stainless bolts that eventually ate threw the battery case. This would have been really messy with a traditional lead acid battery.
The 34-PC1500 batteries we used have the same specifications as the 78-PC1500 batteries we replaced, the only difference is that they have top posts instead of side terminals. Odyssey batteries can withstand both high amperage draws and long drains, making them a deep-cycle and starting battery all in one.
For the Oct. 2017 issue we added a Lund Challenger bed box to our truck to securely store our tools and Power Tank (“Raymundo”; Chris Sparks and Alex Anderson from Rockhound removed the box to determined the best way to securely mount the batteries in the box.
Sometimes off-the-shelf options are the fastest and most economical, but other times you need something custom. Chris Sparks whipped up a new battery tray from scratch to securely hold the Odyssey batteries in place. Since they weigh 50 pounds each, the last thing we want is batteries flying around in the back of our truck.
The custom Rockhound tray places the batteries next to each other behind the Power Tank in our Lund bed box. This still leaves room for our CLC tool bag and tote full of fluids and spare parts.
IBS includes instructions detailing the function of the system and the recommended way to install everything from dual to triple batteries with a winch, solar panel, or fridge. Two LED lights verify the status of the system for easy troubleshooting.
The longer the battery cable, the higher the risk of current drop. For this reason Rockhound recommended that we use 0-gauge, fine-strand copper wire to run from the batteries in the bed of the truck up to the engine, starter, and alternator. The only downside is the slight increase in weight and cost when compared to smaller wire.
Top posts generally allow for higher amperage draws than side post terminals do. These military-style terminals allowed us to just run heavy lugs at the end of our wires and cleanly install and route as many different circuits as necessary, making it easy to wire our dual Odyssey batteries.
Alex Anderson spent hours tracing wires, shortening them, and installing high-quality connectors with shrink wrap for durability. This is time consuming but worth the effort when you have an end product that is simple, reliable, and clean under the hood.
Since the battery cables are running the full length of the chassis there are many opportunities for abrasion. We sheathed all the cables with Painless Performance’s ClassicBraid, which has the perfect look for our 1970s Ford. ClassicBraid is a self-wrapping split braided wiring loom with a smooth texture that looks factory and protects against dirt and abrasion.
Anderson used Blue Sea components to distribute power to the Warn winch, MSD ignition and fuel injection, and chassis wiring. This really cleaned up the engine bay and freed up space where we intend to install a cartridge-style air cleaner before returning to Baja. We appreciate that the Blue Sea buss bar includes a cover to prevent any accidental arcing.
The Swiss-made IBS dual battery relay is the heart of our charging system, yet small enough to mount nearly anywhere. The relay has an integrated microprocessor and is capable of 200-amp continuous current and up to 500-amp spikes. This is the perfect addition to any 4x4 with dual batteries.
Anderson installed a switch on the dash to allow the batteries to be linked by the IBS relay. Hitting the switch automatically links the batteries for half an hour; after that time the system separates the batteries again.
One of the inconveniences of remote battery locations is reaching them to charge them or jump start. Rockhound addressed this with a Blue Sea Powerpost, which allows us to connect a charger or jumper cables under the hood of the truck.
The completed installation is clean and secure. Rockhound even built a plexiglass cover for the batteries so that items like recovery gear could be stuffed into the Lund box without effecting the electrical system.


Painless Performance Products
Odyssey Batteries
Reading, PA 19605
Lund International
Buford, GA 30518
Power Tank
Elk Grove, CA 95758
Slee Off-Road
Blue Sea Systems
Rockhound Off Road

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