Utility Trucks

Understanding 12-volt batteries: Part 2, Fluid depletion and best practices

Northstar battery(HWT Note: This is the second part in a three part series on understanding 12-volt batteries, which includes tips on improving battery function and longevity. The first is titled Understanding 12-volt batteries: Part 1, corrosion in a connected world.) 

Jeremy Cordray, electrical engineer and west region manager at NorthStar Battery Company, continues to answer battery-related questions.

HWT: What generally causes fluid depletion in a battery and how often should the fluid level be checked?

Cordray: Lead-acid batteries have proved over hundreds of years to be a very efficient means of storing the large amounts of energy needed for a typical 12-volt electrical circuit.  The lead-acid battery, unlike other electro-chemical storage, has an electrolyte that is an active participant in the chemical reaction.  Because the electrolyte is so vital to ensuring the battery performs at an optimal level, there has been much innovation surrounding preserving the re-combination elements of lead-acid batteries in the past 30 to 40 years.  The electrolyte is made up of both sulfuric acid and water; during the charge and discharge of the battery the electrolyte chemically changes.  During these changes, there presents the opportunity for water loss through inefficiencies in electrolysis.  For instance, a standard flooded battery allows both hydrogen and oxygen to typically rise to the top of the battery cell prior to recombining into water.  An AGM battery allows for more of a horizontal recombination of the hydrogen and oxygen because of the physical proximity of the plates with only the AGM separator between them.  This is one example of how the electrolyte level may be reduced during the life of the battery.  In today’s world, there is very limited ability to check or add to the electrolyte in automotive batteries.

HWT: What are some tips for extending the life of a truck battery?

Cordray: All batteries are electro-chemical storage devices and therefore will perform differently at different temperatures.  Life can be extended by lowering the temperature at which the battery is operated.  Operating temperature is not only due to the environmental conditions of the vehicle, but other variables can increase the operating temperature, i.e. road heat, engine/exhaust heat, etc., and in most of these cases, the best way to lower the effects of non-ambient temperature increases is encasing the battery in a heat shield to deflect the heat presented by some of these variables.  Besides ensuring that non-ambient temperatures do not hasten end of life, it is most beneficial to ensure proper cycling of any battery.  This starts with selecting the correct battery for the application, but also includes proper charging, ensuring proper connections, and other preventative maintenance procedures based upon the manufacturer recommendations of the battery.

HWT: Some folks will dab a little bit of transmission oil on battery terminals and posts to prevent corrosion. What do you think of that old practice?

Cordray: I am sorry, I am not aware of this practice and have no knowledge of the chemical make up of transmission fluid and therefore the effect on corrosion.

HWT: Battery corrosion preventatives like NCP-2 have been on the market a while. Do you recommend their use?

Cordray: One of the most common mistakes in preventing battery corrosion is the thought that corrosion can be prevented.  The only way to prevent corrosion is to eliminate the chemical elements that make up corrosion, mainly calcium.  If a battery is in use that contains calcium, whether or not you can visually see it, corrosion will always be present as the battery ages.  To prevent the build-up of corrosion at the terminals caused by leakage around the terminals from inside the battery can be reduced with the application of some of these products.  The biggest benefit of these products is to ensure the conductivity of the connections and not to prevent corrosion.