Caring for your Batteries from Birth to Retirement

Isidor Buchmann
Cadex Electronics Inc.
isidor.buchmann@cadex.com
www.buchmann.ca

April 2001

It is interesting to observe that batteries cared for by a single user generally last longer than those operating in an open fleet system where everyone has access to, but no one is accountable for them. In this article we look at two distinct battery users — the personal user and the fleet operator. The article provides suggestions in prolonging battery life and increasing reliability in the rather harsh environment of fleet use.

A personal user is one who operates a mobile phone, a laptop or a video camera for business or pleasure. He or she will 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 will get 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. He 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. Perhaps due to neglect, fleet batteries generally provide a shorter service life than those in personal use.

How can fleet batteries be made to last longer? An interesting observation can be made 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 released, no questions asked. 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 operational costs and improve reliability. The batteries are issued to the soldiers and they 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 on a Cadex battery analyzer to prolong service life. Batteries that do not meet the 80 percent target capacity setting are reconditioned; those that fail to meet the target setting are replaced. The US Army, on the other hand, uses NiMH batteries, which are known to have a shorter service life. The army is evaluating the Li‑ion polymer for the next generation battery.

Battery analyzers for critical missions

The high failure rate of fleet batteries, excessive replacement costs and poor reliability has prompted many organizations to service rechargeable batteries with a battery analyzer on a regular bases. Today, battery analyzers play a critical role in prolonging battery life and maintaining a healthy battery fleet.

Conventional wisdom says that a new battery always performs flawlessly. Yet many users realize that a fresh battery may not always meet the manufacturer's specifications. With a battery analyzer, weak batteries can be identified and primed. If the capacity does not improve, the packs can be returned to the vendor for warranty replacement. Entire batches of new batteries have been sent back because of unacceptable performance. Had these batteries been released without prior inspection, the whole system would have been jeopardized, resulting in unpredictable performance and frequent down time.

In addition to getting new batteries field-ready, battery analyzers perform the important function of restoring weak batteries and weeding out the deadwood. Weak batteries can often hide among their peers. But when the system is put to the test in an emergency, these non-performers stick out like a sore thumb. It should be noted that battery analyzers are most effective in restoring nickel-based batteries. Lithium-based batteries lose capacity mostly due to aging and such performance loss is non-reversible.

Organizations tend to postpone battery maintenance until a crisis situation develops. One fire brigade using two-way radios experienced chronic communication problems, especially during call-outs lasting more than two hours. Although their radios functioned in the receive mode, they were not able to transmit and firefighters were left unaware that their calls did not get through.

The fire brigade acquired a Cadex battery analyzer and all batteries were serviced through exercise and recondition methods. Those batteries that did not recover to a preset target capacity were replaced.

Shortly thereafter, the firefighters were summoned to a ten-hour call that demanded heavy radio traffic. To their astonishment, none of the two-way radios failed. The success of this flawless operation was credited to the excellent performance of their batteries. The following day, the Captain of the fire brigade personally contacted the manufacturer of the battery analyzer and enthusiastically endorsed the use of the device.

Batteries placed on prolonged standby commonly fail when needed in an emergency. A Cadex representative was allowed to view the State Emergency Management Facility of a large US city. In the fortified underground bunker, over one thousand batteries were kept in chargers. The green lights glowed, indicating that the batteries where ready at a moment’s notice. The officer in charge stood erect and confidently said, “We are prepared for any emergency”.

The representative then asked the officer to hand over a battery from the charger to check the state-of-health. Within seconds, the battery analyzer detected a fail condition. In an effort to make good, the officer grabbed another battery from the charger bank but it failed too. Subsequent batteries tested also failed.

Scenarios such as these are common. Political hurdles and lack of funding often make it difficult to solve such problems quickly. A maintenance program in which each battery is cycled on a monthly basis with a battery analyzer would prevent such a problem. In the meantime, the only thing the officer of the emergency facility can do is pray that no emergency will occur.

Figure 1:  Results of battery neglect. The soldier is carrying rocks instead of batteries.
Maintenance helps to keep deadwood out of military arsenal. © Cadex Electronics Inc.

Another user group that relies heavily on batteries is the military. Defense organizations take great pride in employing the highest quality and best performing equipment. When it comes to rechargeable batteries, however, there are exceptions. The battery often escapes the scrutiny of a full military inspection and only its visual appearance is checked. Maintenance requirements are frequently ignored. Little effort is made in keeping track of the battery’s state of health, cycle count and age. Eventually, weak batteries get mixed with new ones and the system becomes unreliable. As a result, soldiers are carrying rocks instead of batteries. A battery maintenance program with battery analyzers keeps deadwood out of the arsenal.

Summary

Unlike individual battery users who know their batteries like a good friend, fleet users must share the batteries from a pool of unknown supply. While an individual user can detect even a slight reduction in runtime, fleet operators have no way of knowing the behavior or condition of the battery when pulling it from the charger. They are at the mercy of the battery. It’s almost like playing Russian roulette.

Increasingly, fleet battery users are setting up a battery maintenance programs. Such a plan exercises all batteries on a regular basis, reconditions those that fall below a set target capacity and ‘weeds out’ the deadwood.

Usually, batteries get serviced only when they no longer hold a charge or when the equipment is sent in for repair. As a result, battery-operated equipment becomes unreliable and battery-related failures occur too often. The loss of adequate battery power is as detrimental as any other malfunction in the system.

Manufacturers of portable equipment support battery maintenance programs. Not only does such a plan reduce unexpected downtime, a well-performing battery fleet makes the equipment work better. If the recurring problems relating to the battery can be eliminated, less equipment is sent to the service centers, a win-win situation for the user and the vendor.

This article contains excerpts from the second edition book entitled Batteries in a Portable World — A Handbook on Rechargeable Batteries for Non-Engineers. In the book, Mr. Buchmann evaluates the battery in everyday use and explains their strengths and weaknesses in laymen’s terms. The 300-page book is available from Cadex Electronics Inc. through book@cadex.com, tel. 604-231-7777 or most bookstores. For additional information on battery technology visit www.buchmann.ca.

About the Company
Cadex Electronics Inc. is a world leader in the design and manufacture of advanced battery analyzers and chargers. Their award-winning products are used to prolong battery life in wireless communications, emergency services, mobile computing, avionics, biomedical, broadcasting and defense. Cadex products are sold in over 100 countries.