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WORKSHOP BA1TERIES

29th October 1998
Page 46
Page 47
Page 46, 29th October 1998 — WORKSHOP BA1TERIES
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Which of the following most accurately describes the problem?

Bungle your battery buying and you'll have nothing but trouble. Chris Graham finds out some of the reasons for this.

HLing on to your hats, because we are

entering the silly season again the time of year when operators scratch their heads, curse their workshop staff and agonise about the cost of downtime. The cause? It's that annual problem which afflicts so many—battery failure.

Year after year Commercial Motor warns of the pitfalls, outlines the solutions and considers the consequences. Yet the problems persist. The moment the first frost strikes, the fun begins. Ironically, the whole business of battery-related vehicle failures is avoidable. The application of common :,:ci Ise combined with a

well-thought-out buying policy is all that's necessary. Is that so much to ask?

The big problem is that, for many operators, buying a battery remains a "distress purchase''. It's something which is begrudged and dreaded. What a shame! The battery is at the very heart of a modern truck. Electrical loading levels grow relentlessly as engine management systems expand and the amount of commonly fitted ancillary equipment mushmoms.

These days the condition and reliable performance of a vehicle's battery are crucial. This means that buying a premium brand is a necessity Guaranteed performance is the key factor, although in some respects this can be a double-edged sword.

There is much talk about guarantee periods, and manufacturers place great emphasis on this in their sales literature and advertising. But how relevant is it?

for example, produces an extensive range of premium-quality vehicle batteries, and offers a two-year warranty on its commercial vehicle products. This is in keeping with other producers and, like them, is subject to the dreaded "small print". In Hella's case the guarantee is dependent upon the correct type of battery being fitted to the vehicle, and applies only if failure is not due to wear and tear, misuse, accident, negligence or the use of any chemical additives not recommended by Hella.

This is a pretty comprehensive list of potential causes of failure and, in practical terms, leaves little else to go wrong apart from an actual manufacturing-related fault. So high are the production standards employed these days by top-flight manufacturers such as

Elena, Hoppecke, Lucas and Varta that CM would guess that fundamental problems are rare.

Hella's John Guppy, manager, auto electrical division, says: If a modern battery is going to fail bemuse of a factory-related problem, it will do so within the first few days of its operation. If nothing happens in these initial stages, it is unlikely to fail thereafter without provocation."

In Italy the standard guarantee period is just six months, and everyone accepts this as normal. Why, then, do we in the UK set such store by extended warranty periods? And are they a genuine safety net or just a marketing tool?

Far more important, on a practical level, is a battery's stated performance potential. This can be gauged in a number of ways with reference to technical data (see panel on facing page). Most top-quality manufacturers publish detailed performance specifications for their batteries which allow comparisons and correct application choices to be made. The German DIN rating is rapidly becoming an industry standard, according to Guppy. He says: "This is a specific standard about which there can be no confusion. It guarantees the user a specific level of cold-start performance. Not all producers build batteries to meet this test."

Matching the battery to the application is a key issue. The electrical specification of many vehicles alters during their operational life, and this must not be ignored. The addition of ancillary equipment or a change in vehicle usage both play vital roles in the loading placed on the battery The quickest way to kill off a battery is to discharge it completely, repeatedly. The reality is that most will stand only two, maybe three, total discharges before becoming unrecoverable—they simply won't accept charge. Although it will be possible to start the engine using a boost charger, the alternator will never be able to recharge the battery adequately from that point onwards.

"Maintenance-free" is another factor touted as a major selling point. It means the battery is completely sealed, apart from gassing vents. Although this is an attractive proposition, there can be problems.

The inability to top up the electrolyte might prove restrictive. The manufacturers will tell you that sealed batteries rarely lose electrolyte. and in ideal operating conditions this is true. But when things go wrong—hot weather, excessive electrical loading, over-charging because of an electrical fault—the ability to top up can be vital.

The other knock-on effect of the "maintenance-free" tag is that it portrays the battery as a "fit and forget" component. This is not the case. The battery's condition should be checked regu larly to ensure the terminals are clean, greased and tight, the battery is mounted securely and its casing is intact. Protective covers should always be replaced and secured.

Modern batteries, although appearing solid and strong, do have their weaknesses. They are vulnerable to impact damage and vibration, which is why firm anchorage is so important. Also, their base plates are a potential weak spot. Loose mounting or careless fitting can mean stones or other debris get trapped between the battery and its tray. This, in turn, can lead to a punctured casing and electrolyte loss.

So ignore your vehicle batteries at your peril—they require care and attention like every other aspect of the vehicle. Their function is vital, but they are often misunderstood.

Guppy concludes: "Most larger fleets are now reasonably well aware of the importance of correct battery specification. Managers and equipment buyers appreciate the need to match the battery to the application, and they understand the importance of premium product quality If only the rest of the industry were similarly aware."

&MIRY STANDAR

SAE 30 A hie-current test conduct with the battery cooled to -18°C and discharged at th current indicated. The requ ment is for the battery volt after 30sec to be 7.2V or it lEC 60 A high-current test with tfu battery cooled to -18°C an discharged at the current indicated. The requirement for the battery voltage aft( seconds to be 8.4 volts or DIN rate The current in amperes tha be drawn from the battery 30 seconds at -18°C beton battery voltage drops bele volts.

RC (reserve capaci Capacity test which shows long a fully charged batter 25°C) can supply a curter 25 amps before the voltagi to 10.5 volts

CHARGING ADVIC

The charging current in arn should be no more than 10 the battery's rated capacii ampere hours (Ali); eg, ch a 100Ah battery at 10 amp High-speed charging using booster should be regarde an emergency measure on

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