Are Dual Purpose Batteries Better Than Conventional Flooded Lead Acid?

By Vicki Hall, Director, Transportation Technical Solutions at EnerSys, ODYSSEY Battery at EnerSys

Whether you rely on a multiple-battery system or a single battery for your work truck, a reliable battery is essential equipment to keep you on the road and operating all the electrical accessories you need. For the best experience, there are some questions you should ask. Are all batteries ideal for multiple-battery systems? Should you use conventional flooded lead acid batteries? What if you can only use one type of battery—which one is best?

Generally speaking, the right battery is the one you can depend on. That means choosing a battery that meets the requirements of the application, performs well and lasts a long time.

While the price of a conventional flooded lead acid battery may appear to be less expensive  upfront, in the long run it can end up costing more. Let’s take a closer look to understand some of the critical differences between dual purpose and conventional flooded lead acid batteries.

Conventional Flooded Lead Acid Batteries

The basic technology of conventional batteries has been around for more than 150 years, and  continue to be widely used, although perhaps, not best suited for every application.

Sometimes referred to as “starter batteries”, these batteries are designed to deliver a large burst of power for a short time, as in starting an engine. The battery is then recharged by the alternator in the vehicle. They consist of a plastic outer case and cover that houses lead plates surrounded by liquid electrolyte (dilute sulfuric acid). Unlike a deep-cycle battery, starting batteries are designed for only shallow cycles. Deep cycling can significantly shorten its life.

All batteries self-discharge when not in use. Flooded lead acid batteries generally have a higher rate of self-discharge and are more dramatically affected by extremes in temperature.

Conventional flooded lead acid batteries also require more maintenance, like water addition, and terminal cleaning to remove any corrosion. Typically, these batteries are somewhat less robust as the cases and covers are not designed for the extreme shock and vibration experienced in commercial vehicle service. Cracks in the cases can cause acid to leak from the battery and vibration can damage internal components. Battery performance can also be dramatically affected by extreme temperatures.

Dual Purpose Batteries

Dual purpose batteries are ideally suited for applications that require both strong cranking power and low-amp draw (cycling) service to meet the extended auxiliary power needs of electrical accessories. Among this class of battery, Absorbed Glass Mat (AGM) sealed batteries are a top performer.

Inside AGM batteries, positive and negative lead plates are separated by an absorbent glass mat that holds the electrolyte, rather than being immersed in electrolyte. The plates and separator are tightly compressed in cells and held within a durable plastic case. This extremely tight compression limits “shedding” of plate material that happens during battery cycling and produces significantly longer battery life. In addition, the compression serves to lower internal resistance and maximize power output, improving performance in colder temperatures.

Deep cycling, dual purpose AGM batteries charge up to five times faster and offer a depth of discharge of 80 percent, compared to flooded lead acid batteries that offer 50 percent for the same rated cycle life.

Sealed AGM batteries experience very little water loss and recombine most gasses within the battery. However, the design of these batteries also features a valve that releases any excess pressure that might occur from minor gassing during charging.

Review and Compare

AGM dual purpose batteries offer many unbeatable advantages over conventional batteries, and some of the key differences are outlined below. Be sure to evaluate how the benefits support your work truck demands:

  • Excellent starting capability
  • Deep cycle performance
  • More starts per battery, up to three times longer battery life
  • Low self-discharge rate
  • Recharges up to five times faster
  • Low maintenance
  • Minimizes surface corrosion
  • Excellent cold weather performance
  • Less prone to sulfation and grid corrosion
  • More durable construction, vibration resistant
  • Non-spill, safer to handle
  • Special valves to protect battery lifespan

When it comes to choosing a battery for your work truck, never was the old saying, “you get what you pay for,” truer. Choosing a quality dual purpose battery will more than pay back the initial cost difference when compared to a conventional flooded lead acid battery, in maintenance, performance and battery life. Always be sure to follow the manufacturer’s guidelines for battery care and handling, and direct any questions to your battery professional.

Learn more about how ODYSSEY® batteries deliver greater reliability and value: Technicians may refer to the ODYSSEY® Battery Technical Manual as a good source of information about how ODYSSEY® batteries work. A copy may be downloaded here.

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