If you’ve purchased a new car in the past year or two, it likely came equipped with a feature called Start-Stop technology. This system automatically shuts off the engine when the car is idling, like when you’re waiting at a stoplight or in the drive-through, then restarts it when you take your foot off the brake.
Although originally used in electric vehicles, start-stop technology is now also common in hybrid and gasoline-powered cars. In 2020, nearly 60% of all new cars sold in the U.S. came with start-stop systems.
The benefits are real — namely, improved fuel efficiency and lower emissions. But behind the scenes, the system depends on one critical component to work properly: the battery.
To function without causing performance issues or shortening battery life, vehicles with start-stop systems require a battery that can withstand frequent cycling and quickly absorb energy, even when it hasn’t been fully discharged. That’s where Enhanced Flooded Batteries (EFBs) come in.
According to Stryten, nearly 30% of the new start-stop-equipped vehicles sold in the U.S. come equipped with an EFB, and that number is growing.
This article takes a closer look at what makes EFBs different, exploring the chemistry, design and real-world performance benefits that allow them to power today’s increasingly advanced vehicles.
What Are EFBs?
Simply put, EFBs are an upgraded version of traditional flooded Lead Acid (FLA) batteries. They’re engineered with specific enhancements that help them perform more efficiently during frequent discharging, a demand that’s typical in modern vehicles equipped with start-stop systems.
These upgrades allow EFBs to handle higher electrical loads and frequent engine restarts without a significant drop in lifespan. That makes them a smart choice for vehicles that start and stop often, where a standard FLA might struggle to keep up.
To better understand where EFBs fit in, here’s a quick comparison of the three most common Lead Acid Battery types found in automotive applications: Conventional FLA, EFB and absorbed glass mat (AGM).
EFB Advantages: What Makes Them Enhanced?
EFBs are advanced Lead Acid batteries designed to handle the increased demand of today’s vehicles, especially those with start-stop systems.
Like conventional FLAs, EFBs use lead plates and a liquid sulfuric acid electrolyte to generate power — but the similarities largely end there. What sets EFBs apart are a series of smart enhancements designed to improve performance and extend battery life under frequent cycling conditions.
What makes EFBs stand out:
- Polyfleece material. Lines lead plates to stabilize active material.
- Carbon additives. Improve charge acceptance and reduce sulfation.
- Special grid designs. Increase electrical conductivity and reduce corrosion.
- Improved cycle life and higher charge acceptance rates.
EFB: A Look Inside
Why EFBs are Better for Start-Stop Systems
Start-stop systems demand more from your car battery than vehicles in years past. Every time the engine shuts off and restarts, the battery is called on to deliver power quickly, reliably and repeatedly.
Here’s why EFBs are built to handle the challenge:
- Designed for frequent cycling. Conventional FLAs are built to start up the engine once, then recharge as you drive. Start-stop requires your battery to go through the processes many times during a single trip. Stronger internal components, including plate reinforcements, allow EFBs to handle frequent charge-discharge cycles and maintain performance even if they’re not fully charged.
- Recharge faster. Carbon additives in the negative plates allow EFBs to take in higher current loads during short driving intervals, meaning they are better at recovering and charging between starts.
- Deliver power even when not fully charged. Since stop-start systems interrupt the charging cycle, EFBs are optimized for use with partial state of charge (PSoC). They can perform reliably even when not fully charged.
- Durable under stress. The EFB’s enhancements make it more resistant to vibration, heat and wear.
Beyond Start-Stop Systems: EFB Applications
EFBs are ideal for start-stop systems in modern cars, but their value goes beyond just one technological advancement.
Over the past two decades, the number of electronic devices in cars has increased by an astonishing 500%. This includes everything from Bluetooth-enabled stereo systems to lane assist, advanced driver assistance systems (ADAS), onboard navigation, dashcams, and even Wi-Fi hotspots. All that power needs a more robust battery, one that can provide reliable performance, even when the engine is off or only partially charging the system.
EFBs are well-suited for today’s cars and driving landscapes (where shorter trips may be the norm), but that’s just the beginning. Thanks to their enhanced capabilities, EFBs work well in a variety of demanding environments and vehicle types.
Regenerative braking. Many electric and hybrid vehicles use regenerative braking to convert the energy typically lost during braking into electricity. The electricity is fed back into the battery. EFBs are designed to handle the rapid charge and discharge cycles caused by regenerative braking.
Warmer climates. The typical FLA lasts about 58 months in northern climates, but as you head south, where temperatures are hotter year-round, that number drops to as low as 41 months. EFB batteries have a higher heat tolerance, making them longer-lasting than FLAs; they also tolerate high temperatures better than AGMs.
Light commercial use. Stop-start benefits don’t only apply to personal vehicles. Service vans, utility vehicles and taxis spend much of the day idling. EFBs recharge quickly and can handle the frequent starts without compromising function or lifespan.
Public safety vehicles. Reliable and more affordable than AGMs, EFBs work well for police cruisers, fire vehicles and ambulances where lights, communication systems and power tools draw energy even when the engine is off.
Rough conditions. EFBs are more resilient than FLAs and are resistant to harsh conditions, such as vibration. They’re also more resistant to sulfation. These qualities make them a good fit for RV and marine use and even some agricultural and construction equipment.
When to Choose an EFB
Not sure if an EFB is the right fit for your vehicle? The first place to look is under your hood. What type of battery came factory-installed? If it is an EFB, that’s a sure sign you can replace it with another EFB.
If your vehicle came standard with an FLA, that doesn’t rule out installing an EFB, especially if you’ve added aftermarket components like a sound system, dash cam or remote starter.
Before replacing your battery, always check with the owner's manual and consult a battery expert. Compatibility matters, especially in vehicles with start-stop systems or higher electrical requirements.
Keep Your Eye on EFBs
EFB adoption is growing in the U.S. and abroad. In Europe, EFBs are set to overtake AGMs as the standard factory-installed battery, thanks to their cost-effectiveness and ability to meet the growing electrical demands of modern vehicles.
Here in the U.S., demand is following a similar upward trend. Today’s cars need reliable, fast-charging batteries that can handle increased electrical requirements, such as stop-start technology.
EFBs are staking their claim as an integral part of our automotive future. Explore our full line of Enhanced Flooded Batteries.
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