Upgrade Options For Your Charging System
Photography by Harry Wagner and courtesy of the manufacturers
Your 4×4 likely came off the assembly line with a single lead acid battery and a single alternator that generates around 90 amps. For the average driver who sticks to paved roads, this is perfectly adequate. Start adding aftermarket accessories and covering miles of remote two-track, and you are well outside of what your vehicle manufacturer ever imagined.
Automotive batteries consist of six electrochemical cells, each producing 2.1 volts through a chemical reaction. Two lead plates are found in each cell with a positive plate and a negative plate. Electrons travel from the positive plate to the negative plate to generate electricity. In a traditional battery, that chemical reaction happens in sulfuric acid inside the cells. The issue for off-roaders is that this acid can leak when subjected to vibration, creating a mess in your engine bay and leaving your battery short on power when you need it most. Vibrations can also cause the lead plates to break loose, short circuiting that cell. Instead of cells that are flooded with a liquid electrolyte, an absorbed glass mat (AGM) battery, such as those offered by Odyssey or Optima, use fiberglass material that is filled with electrolyte. With lead plates and electrolyte-saturated fiberglass mat filling the interior of the battery case, the AGM battery acts as a single solid unit.
What To Look For In A Battery
When purchasing a new battery for your vehicle, the first thing to look at is size, specified in the Battery Council International (BCI) Group Sizing Chart. Group 31, 34, and 78 are the most common sizes used in most 4x4s if you are looking for a drop-in replacement. Also, look at the number and locations of your battery terminals. Cold cranking amps (CCA) are a good indicator of how much power a battery will provide, and you might be surprised how much they vary even amongst the same size batteries. Odyssey’s Group 34 battery is rated at 790 cold cranking amps and Optima’s Red Top battery provides 800 cold cranking amps, while a standard Group 34 lead acid battery only provides 600 cold cranking amps. Another important value is Reserve Capacity (RC) or Reserve Capacity Minutes (RCM). This refers to the minutes a battery can deliver a continuous 25-amp current while maintaining 10.5 volts at a temperature of 80 degrees Fahrenheit.
Dual batteries may be required for extended winching, onboard welding, onboard air, or other activities where the Reserve Capacity of a single battery just isn’t enough. Wiring the two batteries together in series simply adds the amperage of the two together. The Painless Performance Circuit Boss dual battery system provides you with control over your vehicles charging system. A three-position switch enables different power combinations for maximum power while starting, winching, or welding. Painless’ waterproof system uses military spec switches for heavy duty automotive use. When the engine is off, the isolator separates the batteries so that the secondary battery can fully discharge when running your fridge or stereo without affecting the primary starting battery.
For wheeling rigs that sit for a long period of time, you will likely want to purchase a deep cycle battery or keeping your vehicle on a charger when it sits. Optima’s 1200 digital battery charger is designed for AGM batteries. It can replenish deeply discharged batteries and helps extend battery life. Other innovative features include an integrated LED work light with ergonomically designed DC charging clamps, quick set selections that prompt users with easy selection of charge profiles by battery type, and USB charging for iPads, iPhones and other devices such as cameras and phones.
Since they do not give off gas and cannot spill, AGM batteries can be mounted inside the cargo compartment of your 4×4 to free up space under the hood. Remember to make the battery easy to reach though in the event you need to jump start it.
Some batteries use post terminals while others accept ring terminals. The terminals can be located on the side of the battery or the top of the battery. Odyssey offers post terminals that can be added to any of their batteries to retain compatibility with your factory cables.