Observing batteries in everyday life(A)
Batteries have a mind of their own. Their stubborn andunpredictable behavior has left many battery users in awkwardsituations. And yet, the battery is our steady travel companionthat allows us to carry out our activities disconnected from homeand office. In this paper we observe the battery in personal useand fleet applications.
The personal battery user
It is interesting to observe that batteries cared for by a singleuser generally last longer than those operating in an open fleetenvironment where everyone has access to but no one is accountablefor them. A personal user is one who operates a mobile phone, alaptop or a video camera for pleasure or business. He or she willlikely follow the recommended guidelines in caring for the battery.When the runtime gets low, the battery gets serviced or isreplaced. Critical failures are rare because the owner adjusts tothe performance of the battery and lowers the expectation as thebattery ages.
The fleet battery user
The fleet user, on the other hand, has little personal interest inthe battery and has no tolerance for a pack that is less thanperfect. He simply grabs a battery from the charger and expects itto last through the shift. The battery is returned to the chargerat the end of the day, ready for the next person. Regular batterymaintenance is minimal and performance often starts to degradeafter one year of service.
How can fleet batteries be made to last longer? I examined the USand the Dutch Army, both of which use fleet batteries. The US Armyissues batteries with no maintenance program. If the battery fails,another pack is released, no questions asked. Little or no care isgiven and the failure rate is high.
The Dutch Army, on the other hand, has moved away from the openfleet system by making the soldiers responsible for theirbatteries. This change was made in an attempt to reduce operationalcosts and improve reliability. The batteries are issued to thesoldiers and become part of their personal belongings. The resultsare startling. Since adapting this new regime, the failure rate hasdropped considerably and the battery performance has increased.Unexpected down time has almost been eliminated.
It should be noted that the Dutch Army uses exclusivelynickel-cadmium batteries. Each pack receives periodic maintenanceon a battery analyzer (Cadex) to prolong service life. Batteriesthat do not meet the 80% target capacity setting are reconditioned;those that fall below target are replaced. The US Army, on theother hand, uses nickel-metal-hydride, a battery that has higherenergy density but is less durable. The US army is evaluatinglithium-ion batteries for the next generation battery.