Mon, 17 Apr 2000

Technological evolution of cell-phone batteries

Apart from a "hello" or some other warm greeting, I have had recipients answer my call first with "Sorry if the line cuts off, my cell phone is 'lowbat'." Then a click. Then a disconnection.

Well, you might say, why don't they just go and purchase a new battery for their cell phone? Or, why not go to Glodok Jaya, a shopping center in Kota, downtown Jakarta, to get their batteries repaired at very reasonable prices. Thanks to technological advancements, newer versions of replacement batteries usually last longer than the original batteries which came with cell phones.

Indeed, the number of cell-phone users has increased dramatically in recent months. But many of them do not really comprehend how long their batteries will last, though they are racing to buy the most sophisticated, latest models.

Cell phone batteries will last for several years; however, according to some battery manufactures, batteries used on a regular basis should be replaced every year.

It actually depends on the type of battery used. The first batch of cell-phone batteries is the Nickel Cadmium (NiCad), followed by Nickel Metal Hydride (NiMH), Lithium Ion (Li-Ion) and Lithium Polymer.

NiCad batteries are now out of date as NiMHs and Li-Ions are now more popular and have no memory effect, which means users can recharge them at any level. Memory effect occurs when the batteries can no longer hold a full charge, resulting in a so- called "false peak".

There is no need to wait until they are completely discharged before recharging. These batteries will also last two times to three times longer than NiCad types and 30 percent longer.

Battery traders at Glodok even say that they can alter your NiCad packs to be replaced with NiMH, and that users can use their current NiCad charging system. But, for optimum results, it has always been advised to use the actual NiMH charger, to help prevent overcharging and allow for maximum capacity. Overcharging a NiCad has always been a problem, and severely shortens its lifespan. NiMH offers greater talk and standby times than comparable NiCad and do not require discharging entirely prior to recharging.

Li-Ion battery technology is a breakthrough in cell-phone power source option. The batteries are prepared to assure highest quality and customer satisfactory. The advantages include: no memory effect, higher capacity, smaller size, double capacity over NiCad battery, longer lifespan and up to 1,000 times charging cycles. Li-Ion tends to offer the highest energy density for extended talk-times in a lightweight package with the lowest self-discharge rate.

Cell-phone makers are now competing to apply the best in batteries. Motorola was the first to introduce Lithium technology into cell phone applications in 1993. Newcomers like Samsung also apply Li-Ion batteries.

Currently, battery producers are researching Lithium Polymer technology. Few cell-phone makers have tried to apply this technology on their handsets, but get disappointed as it does not meet the required standards.

The type of battery users choose to use with their handsets will determine the length of talk and standby time as well as the total size and weight of the phone.

There are many factors relating to the weight of a battery, including the milliampere hours (mAh) and the design, which is slim or vibrating. (I. Christianto)