EFB or AGM – Which battery do I need?

ou can't always assume that the battery currently installed in a vehicle is the most suitable technology—especially if it has already been replaced. This can also make it difficult to understand why the workshop chose a particular replacement battery. To help with this decision, we’ve summarized the key points to consider when choosing between an EFB and an AGM battery for a vehicle.

EFB Batteries – Ideal for Compact and Mid-Range Vehicles with Start-Stop Systems

EFB (Enhanced Flooded Battery) technology is an advancement of the conventional lead-acid battery. A special polyester fleece material on the surface of the positive plate extends the battery’s service life. EFB batteries also feature low internal resistance, offer twice the number of charge cycles* compared to standard starter batteries, and provide excellent load capacity.

EFB batteries are well-suited for vehicles:

• With basic automatic start-stop systems

• Without start-stop systems but used in demanding conditions (e.g., frequent urban driving)

• Without start-stop systems but equipped with numerous electrical features

If a vehicle was originally equipped with an EFB battery, it can be replaced with the same type. However, if the driver seeks higher performance or has particularly demanding driving habits—such as constant stop-and-go traffic—a more powerful AGM battery may be a better choice.

AGM Batteries – Designed for Upper Mid-Range Cars, SUVs, and Premium Vehicles

AGM (Absorbent Glass Mat) batteries are maintenance-free, leakproof power sources in which the electrolyte is absorbed in a fine glass fleece. These high-performance batteries are ideal for vehicles with advanced automatic start-stop systems and offer excellent cold-start performance.

Thanks to their outstanding cycle stability, AGM batteries can handle frequent engine restarts—such as when a warm engine is turned off and on again in quick succession—without compromising reliability. They also have ample reserve capacity to power onboard electronics during frequent stops while still ensuring a dependable engine start.

An AGM battery is the ideal energy solution for:

• Vehicles equipped with automatic start-stop systems and brake energy regeneration (recuperation)

• Premium cars with extensive features and high-end electrical equipment

Only Replace an AGM Battery with Another AGM Battery

Vehicles equipped with advanced automatic start-stop systems come with an AGM battery as standard. When it’s time for a replacement, only an AGM battery should be used.

Why is the battery choice so restricted?
Modern batteries like EFB and AGM are integrated with the vehicle’s battery management system (BMS) and monitored by a battery sensor. Installing the wrong type of battery can lead to malfunctions in the start-stop system, loss of comfort features, and significantly reduced battery lifespan.

When Is It Recommended to Upgrade from EFB to AGM?

Upgrading from an EFB to an AGM battery is recommended when your vehicle has a high number of electrical consumers or when maximum battery performance and reliability are essential. AGM batteries offer superior power supply, especially beneficial for vehicles with high energy demands and frequent start-stop activity.

One key advantage of AGM technology is improved fuel efficiency, thanks to the more effective functioning of the automatic start-stop system—resulting in long-term cost savings. Additionally, AGM batteries ensure a stable power supply to all onboard systems, even during stop phases and in challenging weather conditions.

Want to find the right battery for your car? Try our Camel Group to get a perfect match.