CHARGING INTO THE FUTURE
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Battery failure still accounts for a surprisingly high breakdown rate. We consider what goes wrong.
The alarmingly high level of truck battery failure, costing the haulage industry dearly each year, highlights a shocking state of affairs! A fundamental lack of understanding, from both vehicle manufacturers and operators, appears to be at the rc)ot of the problem.
Julian Revington, sales manager at Hoppecke Batteries UK (For further details write No 88 on reader reply card), has definite views on the subject. "While the general level of understanding about the function and operation of a truck's battery is improving, there is still a long way to go." he says. "Part of the problem relates to truck specification—batteries are commonly miss-matched with the vehicle, leading to premature failure, unnecessary downtime and wasted money."
In recent times electrical loading levels on trucks have increased dramatically. The growing reliance on electronic engine management to ensure reliability and starting performance, plus the widespread use of cab accessories such as heaters, televisions and phones means that more power is being consumed.
Also of great significance is the electrically operated tail-lift. These place enormous strains on the battery, particularly on delivery vehicles where legislation now dictates that vehicle engines cannot be left running while unattended. John Rant, product engineering & design manager at Lucas Yuasa Batteries (For details write No 87 on reader reply card) considers that the HGV battery market still has much to learn from the automotive sector.
His impression is that "many of the commercial %,ehicle manufacturers are not as effective at load balancing as the car makers. Consequently, it is common for truck batteries to be continually operating in a low state of charge.
The smaller, independent manufacturers in particular do not investigate the intricacies of duty cycles and I doubt if they could give me specific information such as the battery load balance requirements for their vehicles."
Revington believes that a lack of communication between vehicle manufacturers and body builders leads to trouble. He explains: "Manufacturers tend to build a chassis and fit it with a standard battery. The chassis then goes to the bodybuilder who will turn the vehicle into whatever the customer requires—be it a tanker, tipper or delivery vehicle. Normally the battery remains the same whatever the new spec so problems often result.
"The situation is compounded by the operator's understandable tendency to stick with the original equipment battery type when a replacement is needed. Those who do realise there is a discrepancy usually opt to fit a larger, higher capacity battery, but this is not always the answer either."
A battery's life is determined by the number of charge/discharge cycles it can withstand before losing the ability to regenerate itself. This varies quite considerably across the market with those at the bottom of the scale running out of steam after just 50 to 60 cycles.
Hoppeckes Revington says: "A typical truck battery cycle will be induced by an 80% discharge. One overnight stop, with use of heater and other common auxiliary equipment, can easily cause a 20% discharge, so four nights will represent one cycle.
"If you only have 50 to 60 cycles to play with then a cheap battery could well be exhausted within a year. This is why fitting a larger capacity battery is not always the answer to meeting greater consumption needs. Certainly it will solve the problem initially but unless it has improved cycling performance too it will last no longer than the smaller capacity unit."
John Rant says: "Assessing load balance is the key but involves the use of sophisticated computer software. We have this at Lucas and certainly the car manufacturers are keen to make use of it. Unfortunately the commercial sector seems less interested. All they require is a battery to start the engine but that really is not good enough these days."
Battery replacement is a distress purchase at the best of times and a good many smaller operators still opt for the cheapest solution according to Revington. "At the point of sale costs can vary from .£50 to £130. The best approach is to base your choice on previous experience.
"If what you had before lasted for three years then it is obviously up to the job so can be replaced with confidence, assuming that vehicle usage and specification is to remain unchanged."
While many batteries have changed little in design, some have made significant improvements in performance. Modern diesel engines, with their efficient electronic control, are easier to start so cold start capacity is not such an important factor.
Most premium brand manufacturers now balance this reduced cold cranking requirement with an increased current output for powering ancillaries.
The purchasing situation in the UK is complicated by an archaic part numbering system. Revington explains: "On the Continent DIN standard part numbering is used, making assessing amperage easy For a battery marked DIN 64317, subtract 500 from the first three digits to leave 143— this is capacity expressed in ampere hours.
"Unfortunately part numbers in the UK do not use this system—there is no significance in terms of output at all. The obvious assumption is that similarly numbered UK batteries from different manufacturers will have the same output. They may not! Battery ratings can vary by more than 20A between manufacturer." Battery choice can play an important part in reducing workshop costs, both in terms of overall battery life and by minimising downtime caused by failure.
The maintenance requirements are very straightforward. Batteries must be kept clean, securely located and topped up with electrolyte. The term 'maintenance-free' is often applied to the modern product but should be regarded with caution.
The idea that a battery should be a lit-andforget' item is an appealing one but there are drawbacks—such an attitude can lead to costly neglect. Being 'maintenance-five' can mean the battery is completely sealed (apart from the gassing vents). There may be no toppingup potential which in itself can limit life if an over-charging problem occurs.
Electrolyte loss through evaporation is something which Hoppecke have tackled by designing a battery lid which re-condenses the electrolyte before it escapes. Revington explains: "Hydrogen is the potentially dangerous product of a 'gassing' battery. This can cause particular problems if it builds up under a battery cover. Explosion is a risk which should always be considered. Loose connections or the use of jump leads may cause sparking with potentially serious consequences.
On a practical level it is important to realise just how sensitive batteries are to temperature. Often neglected in the summer, electrolyte levels can fall dramatically during hot weather.
Lucas says that at 0°C a battery's cranking performance can be nearly halved while at -18°C it might only be 40% of normal. Cold conditions highlight battery deficiencies.
For best results ensure that terminals are tightly fixed and clean and that the battery itself is securely clamped into position. Batteries are sensitive to vibration so failure to clamp can induce early failure.
Lucas's Bant says he has seen some atrocious lash-ups on HGVs. "Badly fitted batteries often short across to the restraining clamp, especially if they are the wrong size. It shocks me to see the way some professional operators carry on—batteries are fully exposed, clamps are insecure and the terminals are covered with corrosion and dirt."
It is clear that many people still underestimate the importance of the battery as a serviceable item. The largest fleet operators are now looking closely at battery performance, both economically and practically, but there is a reluctance to bother among the rest.
Electrical systems on trucks are set to become progressively more involved making their correct function crucial to effective and efficient vehicle operation. Even now the policy of buying the cheapest battery available is arguably floored on economic grounds alone. In the future electrical supply stability will become paramount and serious operators will have to buy the best available—there will be no justifiable alternative.