What is an EFB battery?

Why carmakers install an EFB battery and whether you must replace it with the same type

An EFB battery may sound like some new kind of battery technology, but they’ve  been used in the European market since 2008. Since the U.S. automotive industry typically follows its European counterparts by approximately ten years, many domestic vehicles with start/stop technology began using EFB (enhanced flooded battery) batteries around the 2015-18 model years.

What makes it better than a standard battery?

• Provides more start cycles — Can provide up to 85,000 engine starts compared to only 30,000 starts from a standard flooded batter. That’s an important difference especially in vehicles equipped with start/stop technology.

• Prevents acid stratification — Acid stratification is caused when the sulfuric acid settles to the bottom of the battery causing significant lead plate degradation in standard flooded batteries. EFB batteries reduce acid stratification by adding acid recirculation funnels that utilize vehicle movement to circulate the electrolyte, keeping the electrolyte in a more homogeneous density for more power production.

• Incorporates a special polyfleece scrim material that lines each of the vertical lead plates inside the battery.The polyfleece lining helps to prolong the life of the lead material. The polyfleece also holds the newly converted electrons closer to each lead plate, allowing for a more consistent power flow out of the battery.

• Have thicker plates — Thicker plates allow the battery to be discharged to a much deeper level than a normal car battery

• Improves the battery’s ability to accept a recharge. In Dynamic Charge Acceptance tests, EFB batteries showed charge acceptance on par with AGM batteries but at a lower initial cost compared to AGM batteries.

•  Can better handle high temperatures compared to an AGM battery. Tests show that they last 52% longer than an AGM battery in high-temperature environments.
Can you replace an EFB battery with a different type?

That depends on the vehicle. If yours has a start/stop system, you can replace an EFB with a standard SLI flooded battery. An SLI battery can’t handle the requirements of a start/stop system.

And, you really shouldn’t replace it with an AGM battery either. AGM batteries require a different charging routine than SLI or EFB batteries. They must be charged at a lower voltage than either of those. You can only use an AGM if you have no other choice.

For more information on EFB batteries, click on this link to Exide’s page

©, 2023 Rick Muscoplat