EFB Batteries are 'Enhanced Flooded Batteries'. Flooded means 'wet' / filled with a mixture of acid and water. The vast majority of motor vehicle batteries when sold, are 'wet' charged and ready to use straight away.
A 'Dry' cell battery, such as the one in your phone or remote control, by contrast does not have battery acid. It uses the opposite in the form of an alkali which in compacted, powder or gel form is fine around the home but not fine when not exposed to heat. They usually explode, hence not a good DIY car battery alternative....
When a car battery is described as an 'Enhanced Flooded Battery' the internal structure of the standard lead acid battery has been improved on.
In the past, most car batteries were good for 4 to 6 years with regular use. Many modern cars, however, use what's known as 'start-stop' technology to save fuel when the vehicle is at standstill in traffic. For these vehicles the use of AGM and EFB batteries is necessary.
Current vehicle models to feature the technology include the Fiat 500 Start-Stop version, the Toyota Yaris Start-Stop version and the Ford ECOnetic range.
Each of these vehicles will stop the engine in traffic but works the battery harder. When the engine is 'off' the battery is not receiving a charge. If you have the Air Conditioning, Stereo, Satnav etc running at this point an ordinary battery would be overworked / drained too much. AGM and EFB units can handle the extra punishment whereas ordinary car batteries cannot go below a certain charge level and effectively bounce-back.
The improvements to EFB car batteries include the use of a special polyfleece material that lines each of the vertical lead plates inside the battery.
When battery acid comes into contact with each lead plate a chemical reaction creates electricity. The compromise being that with use the lead plate partially degrades whilst losing or gaining electrons and becomes 'sulphated' / encrusted. Over time the battery becomes less effective and effectively 'wears out'.
The polyfleece lining helps to prolong the life of the lead material whilst holding newly converted electrons closer to each lead plate. This allows for a more consistent power flow out of the battery and is necessary to keep the battery healthy when the engine switches off at traffic.
Additionally - in both EFB and AGM batteries the lead plates are also physically thicker. Thicker plates allow the battery to be discharged a lot deeper than a normal car battery and act more like 'leisure batteries' as in the ones used on Motor Homes, Boats etc.
How do EFB batteries differ from AGM batteries ?
AGM batteries use a technology called 'Absorbed Glass Matt'. The separators between the lead plates in this case are made from a fiberglass composite material that further enhances the performance of the battery. AGM batteries are spill-proof and can take extremes in outdoor temperatures.
For more information about EFB and AGM car batteries please visit : www.advancedbatterysupplies.co.uk/batteryjargonbuster.html