Laptop Battery Introduction

With the switch to secondary batteries, some level of battery maintenance is require, a service that is best performed with a battery analyzer. Here are some field results on the use of battery (SONY Vaio VGN-FZ battery  )analyzers:
At the conclusion of the Balkan War, the Dutch Army serviced all batteries at the Dutch Military Headquarters using Cadex 7000 Series battery analyzers. The army was aware that the packs were used under the worst possible conditions. Rather than a good daily workout, the NiCds were employed for short patrol duties lasting 2 to 3 hours per day. The rest of the time the batteries remained in the chargers for operational readiness. The batteries (Sony VGP-BPS10 battery  ).were 2 to 3 years old.

The capacity on some packs had dropped from 100 percent nominal to 30 percent. With the analyzer’s recondition function, 9 out of 10 batteries were restored to full service. The Dutch Army sets the target capacity threshold for field acceptability to 80 percent.

The importance of exercising and reconditioning NiCd batteries with a battery analyzer is emphasized by another study carried out for the US Navy by GTE Government Systems in Virginia, USA. To determine the percentage of batteries ( VGP-BPS10 battery ) needing replacement within the first year of use, one group of batteries received charge only (no maintenance), another group was periodically exercised and a third group received recondition. The batteries studied were used for two-way radios on the aircraft carriers USS Eisenhower, USS George Washington, and the destroyer USS Ponce.

With charge only (charge-and-use), the annual percentage of battery failure on the USS Eisenhower was 45 percent (see Figure 4). When applying exercise, the failure rate was reduced to 15 percent. By far the best results were achieved with recondition. The failure rate dropped to 5 percent. Identical results were attained from the USS George Washington and the USS Ponce. Recondition is a secondary discharge that removes the remaining battery ( Sony VGP-BPS8 battery  ) energy by slowly draining the cells towards zero volts.

Figure 4: Replacement rates of NiCd batteries. The need to replace batteries decreases by three and nine-fold respectively when exercise and recondition is applied. These statistics were drawn from batteries  used by the US Navy on the USS Eisenhower, USS George Washington and USS Ponce.

The GTE Government System report concluded that a battery analyzer featuring exercise and recondition functions costing $2,500US would return its investment in less than one month on battery savings alone. The report did not address the benefits of increased system reliability, an issue that is of equal if not greater importance, especially when the safety of human lives is at stake.

Battery analyzers are also used to quick-test battery (Sony VGP-BPS9 ) performance. Cadex Electronics has introduced a technique to measure the state-of-health of a battery in three minutes. Based on inference technology, the Cadex Quicktest™ uses battery specific matrices that are derived through a “trend learning” process using artificial intelligence. The ability to self-learn enables the system to adapt to new battery chemistries without changing hardware.

Quicktest™ is available on the Cadex 7200 two-station and the 7400 four-station battery analyzer/ reconditioners. The system accommodates Li-ion, NiMH, NiCd and lead acid batteries; the required charge level is 20 to 90 percent. If outside this range, the analyzer automatically applies a brief charge or discharge. The matrix is stored in the battery adapters that also hold the battery parameters to configure the analyzer. Testing a battery (Dell XPS M1210 battery  ) with a properly learned matrix achieves an accuracy of +/-5 percent on most batteries. Popular battery adapters include the matrix at time of purchase. For other batteries, the matrix can be obtained by running the analyzer’s Learn program.

Summary

Primary batteries will always be around, if only to run wristwatches, portable entertainment devices and flashlights. While the primaries were once the only practical power source for portable applications, there is a shift towards rechargeables. Ever since Neumann successfully sealed the NiCd battery in 1947, the era of rechargeable batteries  had begun. The 1990s brought many improvements in terms of higher energy densities and lower costs. But the portable world is not yet satisfied – we need smaller batteries that last longer.

Will the chemical battery (Dell Vostro 1310 battery ) retains its status or does the future lie in fuel cell or atomic fusion? Hype put aside, we are still years away from any practical alternative solution.