Start-Stop Batteries

Posted on 03 Mar 2016 by

In the old days, car battery manufacturers used to use words like "heavy duty", "super heavy duty", and similar to try and make their batteries sound a bit different. The trouble is that "heavy duty" is a matter of opinion, not fact, so heavy duty from a low-end manufacturer wouldn't even be as strong as a standard battery from a quality manufacturer. In the end, all car batteries do a pretty heavy duty job, but the words on the label don't tell you much about what is inside the case. That's where a battery specialist earns their money!

Over the last few years, many car manufacturers have been releasing start-stop technology, where the engine stops at traffic lights etc and comes on, again, when you release the brake, turn the steering wheel etc. It's estimated that as much as 70% of European car sales in 2016 will be stop-start, and several manufacturers have been supplying these in Australia for a few years now. The bottom line with stop-start is that it puts a huge load on the poor old car battery, which often has to start the car 20 or 30 times more often than in a non stop-start vehicle. As a result, battery manufacturers have needed to design batteries that are used to being worked harder, drained more deeply and recharged more often, as well as punching a start more quickly and doing so when partially discharged. Some use their AGM (absorbed glass mat) technology, which is a battery with a glass matting between the plates that absorbs the acid, punches harder, charges quickly and costs a lot to make. Others, mainly due to the cost of AGM technology, have opted for EFB technology (Enhanced Flooded Battery) where the battery is, in most areas, the same as the standard battery, but something has been changed to make the battery cope with start-stop conditions. The changes are often quite small - a polyester scrim on the positive terminals, more tin, different plate design, tighter manufacturing controls, etc, but the difference is huge. A standard (heavy duty) battery in a stop-start car might be dead within 6 months, whereas a good EFB should carry, at least, a 2 year warranty. There's a price to pay, of course, usually around 50% extra on the cost of the battery, but this differential might reduce as stop-start batteries become more common and manufacturing volumes go up.

For now, if you have a start-stop car, don't be tempted to try and get away with a standard battery. It won't be much fun to put up with slower starts, and you'll be reaching for your wallet,again, far too soon.