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Batteries seem to have a mind of their own. Their stubborn and unpredictable behavior has left many battery users in awkward situations. In fact, the British Army could have lost the Falkland War in 1982 because of uncooperative batteries. The army assumed that a battery would always follow rigid military specifications. Not so. When the order was given to launch the portable missiles, nothing happened and the missiles did not fly that day. Such battery-induced letdowns happen on a daily basis. Some are simply a nuisance, others have serious consequences.
In this section we examine what the user can reasonably expect from a battery. We learn how to cope with the many moods of a battery and how to come to terms with its limitations.

Personal Field Observations
While working with General Electric, I had the opportunity to examine the behavior of many NiCd batteries for two-way radios. I noticed a trend with these batteries that was unique to NiCd. These particularities repeated themselves in various other applications.

A certain organization continually experienced NiCd battery failure after a relatively short service time. Although the batteries performed at 100 percent when new, their capacity dropped to 20 percent and below within one year. We discovered that their two-way radios were under-utilized; yet the batteries received a full recharge after each short field use.

After replacing the batteries, we advised the organization to exercise the new batteries once per month by discharging them to one-volt-per cell with a subsequent recharge. The first exercise took place after the batteries had been in service for four months. At that stage, we were anxious to find out how much the batteries had deteriorated. Here is what we found:

On half of the batteries tested, the capacity loss was between 25 to 30 percent; on the other half, the losses were around 10 to 20 percent. With exercise — and some needed recondition cycles — all batteries were fully restored. Had maintenance been omitted for much longer, the probability of a full recovery would have been jeopardized.

On another occasion, I noticed that two-way radios used by construction workers experienced fewer NiCd battery problems than those used by security guards. The construction workers often did not turn off the radios when they put down their hammers. As a result, the batteries got their exercise and kept performing well until they fell apart from old age. In many cases the batteries were held together with electrician’s tape.

In comparison, the security guards pampered their batteries to death by giving them light duty and plenty of recharge. These batteries still looked new when they had to be discarded after only 12 months of service. Because of the advanced state of memory, recondition was no longer effective to restore these batteries.

On a further application, I studied the performance of a two-way radio that was available with batteries of different capacities. It soon was apparent that the smaller battery lasted much longer, whereas the larger packs needed replacing more often. The small battery had to work harder and received more exercise during a daily routine.

Equipment manufacturers are aware of the weak link — the battery. For a more reliable energy source, higher capacity batteries are recommended. Not only are oversized batteries bulky, heavy and expensive, they hold more residual charge prior to recharge than smaller units. If the residual energy is never fully consumed before a recharge, and no exercise is applied, the nickel-based battery will eventually lose its ability to hold charge due to memory.

On the lithium and lead-base systems, a slightly oversized battery offers an advantage because the pack is less stressed on deep discharges. The battery does not need to be discharged as low for the given application. A high residual charge before recharge is a benefit rather than a disadvantage for these chemistries

It is interesting to observe that batteries cared for by a single user generally last longer than those that operate in an open fleet system where everyone has access to, but no one is accountable for them. There are two distinct groups of battery users — the personal user and the fleet operator.
A personal user is one who operates a mobile phone, a laptop computer or a video camera for business or pleasure. He or she will most likely follow the recommended guidelines in caring for the battery. The user will get to know the irregularities of the battery. When the runtime gets low, the battery often gets serviced or replaced. Critical failures are rare because the owner adjusts to the performance of the battery and lowers expectations as the battery ages.

The fleet user, on the other hand, has little personal interest in the battery and is unlikely to tolerate a pack that is less than perfect. The fleet user simply grabs a battery from the charger and expects it to last through the shift. The battery is returned to the charger at the end of the day, ready for the next person. Little or no care is given to these batteries. Perhaps due to neglect, fleet batteries generally have a shorter service life than those in personal use.

How can fleet batteries be made to last longer? An interesting contrast in the handling of fleet batteries can be noted by comparing the practices of the US Army and the Dutch Army, both of which use fleet batteries. The US Army issues batteries with no maintenance program in place. If the battery fails, another pack is issued. Little or no care is given and the failure rate is high.

The Dutch Army, on the other hand, has moved away from the open fleet system by making the soldiers responsible for their batteries. This change was made in an attempt to reduce battery waste and improve reliability. The batteries are issued in the soldier’s name and the packs become part of their personal belongings. The results are startling. Since the Dutch Army adapted this new regime, the failure rate has dropped considerably and, at the same time, battery performance has increased. Unexpected down time has almost been eliminated.

It should be noted that the Dutch Army uses exclusively NiCd batteries. Each pack receives periodic maintenance to prolong service life. Weak batteries are systematically replaced. The US Army, on the other hand, uses NiMH batteries. They are evaluating the Li-ion polymer for the next generation battery.

Because of the high failure rate of fleet batteries and the uncertain situations such failures create, some organizations assign a person to maintain batteries. This person checks all batteries on a scheduled basis, exercises them for optimum service life, and replaces those that fall below an accepted capacity level and do not recover with maintenance programs. Batteries perform an important function; giving them the care they deserve is appropriate.

With the increasing volume of batteries in circulation, battery manufacturing is outpacing the supply of suitable equipment to test these packs. This void is especially apparent in the mobile phone market where large quantities of batteries are being replaced under warranty without checking or attempting to restore them. The dealers are simply not equipped to handle the influx of returned batteries, neither is the staff trained to perform this task on a customer service level. Testing and conditioning these batteries is a complex procedure that lies outside the capabilities of most customer service clerks.
With the move to maintenance-free batteries and the need to test larger numbers of batteries, the function of battery test equipment is changing. Lengthy cycling is giving way to quick testing, improved battery preparation and better customer service. This shift in priority is especially apparent in the rapidly growing consumer market. In this chapter we examine modern battery analyzers and how they adapt to the changing needs of battery service.

Conditioning Chargers
Charging batteries is often not enough, especially when it comes to nickel-based chemistries. Periodic maintenance is needed to optimize battery life. Some innovative manufacturers offer chargers with conditioning features. The most basic charger models feature one or several bays with discharge opportunity. More advanced chargers include a display to reveal the capacity.

Some chargers offer pulse charge methods. This is done to improve charge efficiency and reduce the memory phenomenon on nickel-based batteries. Optimal charge performance is achieved by using a pulse charge that intersperses discharge pulses between charge pulses. Commonly referred to as ‘burp’ or ‘reverse load’ charge, this charge method promotes high surface area on the electrodes and helps in the recombination of the gases generated during charge.

Some manufacturers claim that the pulse charge method conditions and restores NiCd batteries and makes the periodic discharges redundant. Research carried out by the US Army has revealed that pulse charging does reduce the crystalline formation on the NiCd battery. If properly administered, batteries charged with these pulse chargers prolong service life. For batteries with advanced memory, however, the pulse charge method alone is not sufficient and a full discharge or recondition cycle is needed to break down the more stubborn crystalline formation