Friday, March 20, 2009

Which will give the most bang for your buck?

Which will give the most bang for your buck?
Mar 21, 2009
The Straits Times, Digital Life

by Tan Chong Yaw

Compared to old-technology carbon zinc batteries, alkalines cost about 35 cents more per battery but they pack more power and store longer.

Which will give the most bang for your buck? Alkalines, the new-fangled lithium ones or the stalwart carbon zinc batteries?

DL did a shootout of five types of batteries (See table). These range from amazingly cheap carbon zinc PenesamiG batteries to the Panasonic Evolta - a super alkaline - and Energizer e2 lithium.

In the middle are the ones that line most supermarket shelves - alkalines like the Duracell and Energizer Max.

The batteries were bought from FairPrice supermarkets except the PenesamiGs, which were bought at Sheng Siong Supermarket.

A flashlight and camera were used to test the single-use AA batteries.

The flashlight has one light-emitting diode (LED) bulb and runs on a single AA battery. The time taken from the moment the flashlight was switched on until the light died was recorded.

The test camera was Canon's PowerShot SX1 which uses four AA batteries. With the LCD switched on and flash firing for every shot, the number of shots snapped until the camera shut down on its own was noted.

Clearly at the bottom was the PenesamiG - it could not even power up the camera and lasted a paltry three minutes in the flashlight.

In the camera test, the e2 tied with the Max in being cheapest to run on a cost per photo basis. However, the e2 lasts longer than four Max batteries.

The Max and Duracell, both alkalines, tied for being most economical to run in the flashlight test.

Alkalines are best-sellers because they offer a good performance-cost balance. Alkaline batteries make up about 70 per cent of FairPrice's battery sales, said Tng Ah Yiam, its integrated purchasing director.

Photo: ST, Ashleigh Sim

Watt's the difference?

WE GIVE the lowdown on three kinds of batteries.

Carbon zinc

This grandfather of dry cell batteries first appeared on the market in 1887. The battery uses a zinc chloride and ammonium chloride electrolyte with a cathode of manganese dioxide and carbon, and a zinc anode. Great for low-drain devices like clocks, remote controls and radios.

Price per battery: 5 to 55 cents
Good: Cheapest and lightest at 12-15g
Bad: Least powerful; shortest shelf life of three to five years


Alkaline batteries made their debut in 1959 using an alkaline electrolyte of potassium hydroxide - instead of the acidic one in the carbon zinc battery - upping the battery's power and shelf life.

Price per battery: 85 to 95 cents
Good: Shelf life of five to seven years; works at temperatures down to minus 18 deg C
Bad: Heaviest at 24g


This new kid on the block appeared in 1989. Not to be confused with rechargeable lithium-ion batteries although both use the same metal - lithium.

These batteries have a lithium anode, iron disulphide on aluminium foil cathode and a lithium salt electrolyte. Lithium is so flexible, batteries can be built with almost 20 times more active area than alkalines.

Lithium batteries have the longest shelf life and juice in powering tech devices like digital cameras. It can be used for any purpose - if you can afford it.

Price per battery: $3.80
Good: Most powerful and lightest at 15g; shelf life of 10 to 15 years; operates in very low temperatures - down to minus 40 deg C.
Bad: The price

by Tan Chong Yaw

Dos and don'ts

  • Abused batteries will leak or explode. Abuse includes: inserting them upside down in the device, peeling off the label - they act as the battery's insulation - and carrying them loose in your pocket where coins and keys may short circuit them. Put one close to extreme heat like a fire and it will explode.

  • Batteries that continue to be drained after they are exhausted will leak. If you will not be using a device for some time, remove the batteries. Even when turned off, poorly designed devices will continue to drain the batteries.

  • Do not mix battery types (use the same type from the same brand) or mix old batteries with new ones. The more powerful batteries may cause the lower capacity ones to fail prematurely, leading to shorter life or leakage.

  • Store batteries in a cool place. An alkaline battery stored at 20 deg C has almost twice the shelf life - more than seven years - than one at 40deg C according to the 2008 edition of the Energizer Alkaline Handbook.

This article was first published in The Straits Times Digital Life.

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