With the addition of components such as sensors, cameras and collision mitigation radar, truck batteries are more challenged than ever. More truck owners are seeing the advantage of absorbed glass mat batteries, which offer an attractive tradeoff of longevity and other attributes for their higher price, said Jeff Barron, research lab manager for Interstate Batteries.
“AGM batteries are more efficient than your typical flooded battery,” Barron said. “They have a lower internal resistance and will charge faster.”
Emissions systems and alternative fuels also contribute to increased cranking power needs, while anti-idle legislation has made increased charge acceptance more valuable, said Vicki Hall, director of transportation technical solutions for EnerSys.
“Add on to that tighter restrictions on drive time and more electrical loads operating while the vehicle is off,” Hall said. “All of this means batteries have to perform better than ever through an increasing variety of conditions.”
Many battery types can handle some of these challenges, but none as well as AGM thin plate pure lead (TPPL) batteries, said Bryce Gregory, a product manager for EnerSys.
“They offer a true dual-purpose battery that has higher power for starting even at low states of charge, better cycling for long life and reliability, and better charge acceptance to handle the worst conditions,” Gregory said.
AGM batteries cost more than comparable flooded batteries. The spread can vary widely, as much as nearly double the price.
Conventional flooded lead acid batteries feature positive and negative lead alloy plates distributed among delicate separators immersed in an electrolyte solution of dilute sulfuric acid. An AGM battery contains a fiberglass separator between each pure lead plate to absorb the electrolyte. This makes the battery leakproof and eliminates the need for additional fluid.
“Pure lead batteries self-discharge at a much slower rate than batteries containing lead alloy, which means an AGM TPPL battery can have a shelf life of up to two years before it needs to be recharged, when stored at room temperature,” Gregory said.
An AGM battery also is less prone to sulfation and, since the plates and separators are compressed, offers better shock and vibration resistance.
AGM batteries’ “deep-cycle abilities also allow them to power accessories and systems when needed, such as winches, auxiliary lights, A/C compressors, navigation systems, as well as start/stop applications,” Hall said.
Switching from flooded batteries to AGM, Gregory and Hall agreed, should be fairly straightforward. Both said all batteries in any series or parallel configuration should be changed together. Take note of any differences in terminal types or configurations, which can impact battery cable connections. “Be sure to purchase the same terminal type to facilitate an easy change,” Hall said.
“Charging settings are also different between flooded and AGM batteries,” Gregory added. “Additionally, make sure you have chargers that support AGM charging.”