Calls and website queries from customers about EFB batteries have been coming in thick and fast to the Rotronics team; what are they, what do they do, and how do I test them? There seems an air of mystery about these batteries and how to look after them. The reality is that there is no mystery at all. PMM has asked Rotronics, the UK partner for Midtronics and CTEK, to explain more.
EFB batteries are an enhanced version of standard wet-flooded technology. These types of batteries should not be confused with standard flooded or AGM batteries. The primary benefits of EFB technology is improved charge acceptance and greater cyclic durability when operating in a reduced state of charge. As an approximation, EFB batteries will provide 85,000 engine starts, compared to 30,000 starts from a standard flooded product.
EFB batteries offer a cost-effective solution for start-stop vehicles, to meet the EU emissions targets, and manufacturers have developed battery technology which will meet the demands of start-stop operation in a higher state of charge than would be expected from AGM technology. This is delivered at a lower state of charge than that expected of standard wet-flooded starter batteries. Some EFB batteries can be tested using standard flooded test algorithms, however there are many that test inaccurately and subsequently deliver misdiagnosis through over-reading the batteries’ measured CCA value.
The only true EFB testing platform on the market comes from Midtronics, the company says, with the MDX655P or MDX 545 Start/Stop Testers. A comprehensive EFB drop down part number look up table ensures technicians accurately test and diagnose batteries using specific test algorithms. EFB’s can be charged using standard modern intelligent chargers (no specific charging pattern, unlike AGM batteries).
EFB batteries have been introduced as a lower tier option to AGM batteries in terms of performance and durability. EFB technology relies on improvements to existing flooded technology through the addition of carbon additives in the plate manufacturing process. AGM batteries benefit from the inclusion of unique design features not found in wet-flooded batteries. These include glass mat separators, recombinant lid technology and higher pack pressures to facilitate improved cyclic lifespan. AGM batteries are better suited to meeting the demands of higher specification vehicles that include one or more of the following technologies: start- stop, regenerative braking and passive boost.