Although starter batteries may not have changed much in appearance over the last forty years, internally, technological advances have been made to ensure that they keep up with modern demands. Matthew Beecham reports.

The power required by electrical components and systems in a car has steadily increased over the last decade.   The main reason for that is explained by the growing number of electrical and electronic safety and convenience systems now being fitted.  The increasing use of power-hungry options in modern passenger cars is placing unprecedented demands on automotive batteries. 

While such features help to make cars safer and comfortable, they also increase the consumption in electrical energy.  Today, the power consumption of a mid-range car typically exceeds 3,500 watts.  In the mid-1990s, however, the value for a similar sized car amounted to just 950 watts.   To compound the problem, the operating environment has become far more hostile.  Under bonnet temperatures now range from 75 - 100ºC.  Today's battery must also cope with an increasing number of shorter stop-start journeys at lower average speeds, leading to a greater drain on the starter battery.

Batteries for these new electrical power systems represent a particular area of focus for most battery producers. For aftermarket applications, Bosch has developed a 'HighTec' battery with AGM (Absorbent Glass Mat) technology. The new battery line is maintenance free, spill and leakage proof and shock resistant.  Banner has also been busy developing AGM battery technology for the aftermarket.   Using AGM technology, Banner is able to install batteries upside down or in the lateral position without losing liquid.  This is possible due to a highly porous nonwoven mat made of AGM which absorbs the liquid electrolyte in its entirety and thus binds it in.  In addition, the battery casing is entirely sealed and fitted with an over-pressure valve. 

In addition to the traditional requirements relating to vibration and cycle resistance, the demand for ease of maintenance and operational safety, already largely standard in the car sector, is gaining in significance in the commercial vehicle segment. Furthermore, commercial vehicle batteries must now serve a growing number of additional electronic users and comfort features. One of the notable features of Banner's SHD (Super High Duty) battery is the use of a calcium alloy on the negative electrode to minimise water consumption and cut self-discharge. Compared to conventional batteries, this results in a 50% increase in battery storage capacity.

Other novel features include a PE bag separator with set bonding to improve vibration resistance. In addition, Banner has developed special safety screws, flat sealing and backfire protection to prevent leaking acid due to extreme tilting or vibration.

Varta is also actively pursuing the commercial vehicle market.  The company recently added a new 180 amp/hour SHD battery to its PROmotive range.  The new battery is suitable for a number of European heavy truck applications.  The company's batteries provide up to 70% coverage of the current European commercial vehicle market.   "When a truck breaks down to battery failure, the costs are considerable," said Tony Miller, product manager, Varta.  "As well as roadside assistance and replacement battery costs, there is time off road, missed deliveries, possible loss of cargo in the case of refrigerated loads and customer dissatisfaction."  Based on the average service life of a commercial vehicle battery, Varta calculates that adoption of PROmotive batteries would save £30 - £40 per battery on regular maintenance costs.

As part of a standard 12 volt vehicle electrical system, the battery represents a compromise between conflicting requirements. Its capacity must be selected with reference to starting requirements, as well as on-board current supply. Future vehicle electrical systems may feature two batteries: a starter battery and a general purpose battery. According to Bosch, the "high power for starting" and "general purpose electrical supply" functions will be separated. This will make it possible to avoid the voltage drop during the starting process, while ensuring reliable cold starts, even when the charge level of the general purpose battery is low, says Bosch.

Starter batteries provide a short burst of power to start a vehicle's engine. By contrast, deep cycle batteries provide a long lasting, low, steady supply of power for electrical accessories such as on-board computers, navigation devices, electric seats and windows, as well as for audio systems.

Despite the merits of a twin-battery system, the prospects for widespread application appear slim.   "There are a handful of cars coming out with dual battery systems," said Paul Martarewicz, managing director, Varta Batteries UK.  "I think the big question mark is what happens with hybrid vehicles.  That is our big unknown.  Although we believe that closed loop hybrid has a clear future, [vehicle manufacturers] are still hedging around which technology is best to use and on which vehicles. But we believe that they will be effectively forced down that path within the next ten years. But that won't necessarily be lead-acid. That could well be some other kind of technology. It depends on which technology wins out, which manufacturer makes it most available, cost-effective and reliable. But we believe that there will be a massive increase in hybrid vehicles over the next ten years."

Another notable trend in the battery aftermarket relates to the sheer complexity of the starter battery itself and the extent to which an independent garage has the know-how and equipment to install a replacement battery.   "We are starting to see the beginning of the demise of the straight forward 'walk-out battery market'," added Martarewicz.  "I'm talking about the accessory shop.  The reason is that trying to fit a battery nowadays is actually quite technical.  It used to be well known that fitting a battery to an Audi or a Mercedes or a Porsche was risky.  But that risk has permeated down to the likes of an Audi A4, A3, VW Golf and Ford Focus.  So to walk into a shop and buy a starter battery £50 is only quarter of the problem. So it will be interesting to see whether the accessory shops are will to invest in fitting."

Günther Lemmerer, marketing manager, Banner GmbH, agrees.  He said:  "For consumers, it is very dangerous to try to fit a replacement battery.  The problem is the tension.  Today, you have electronic devices such as the alarm, and other devices.  If you change the battery and interrupt the tension then all these devices with malfunction so that you cannot start your engine or enter the car.  So you have to use a device that simulates the vehicle's tension.  But the carmakers say that if you cause damage by changing your battery then you may lose your warranty.  The starter battery has become an increasingly prohibited area for consumers.    But for a trained independent garage with the right equipment, it should not be a problem."
The automotive starter battery industry is consolidating in a similar way to the tyres industry during the 1980s. Three valve regulated lead acid battery manufacturers - Exide Technologies, GS Yuasa, and Johnson Controls—have emerged as global players.  Likewise, the last 20 years have seen a dramatic concentration in the number of major tyre manufacturers in the market -- five of the ten largest companies in 1981 have now been taken over by competitors. 

Above all, the global automotive battery market remains highly competitive.  Manufacturers compete on price, quality, technical innovation, service and warranty.   OEM sales of batteries are driven mainly by new vehicle build sales, which are driven by consumer demand for vehicles.  Meanwhile, battery aftermarket sales are driven by a number of factors including the number of vehicles in use, average battery life, average age of vehicles, average miles driven, weather conditions and population growth.  Indeed, the aftermarket is shaped by a number of factors, notably the buying power of large customers such as supermarkets, fast fitters and auto centres.  The main buyers consist of a limited number of large, knowledgeable and price-sensitive companies that are in a position to obtain more favourable purchasing conditions.
While lead-acid starter batteries may not appear to have changed over the last four decades, internally, technological advances have been made to ensure that they keep up with modern vehicle demands. Lead-acid is still, and will continue to be, the most dominant technology used in starter batteries due to cost considerations.  For this reason, lead-acid batteries will continue to start cars for many years, but the search continues for lighter, more efficient and cleaner replacements.
Matthew Beecham

See also: Global market review of automotive batteries - forecasts to 2012 (download)