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Friday, July 1, 2011

Combining the powers of disposable and rechargeable batteries – the new Eneloop of SANYO

In day to day life, we use various gadgets and most of them work on battery – we use them in our Cars, PCs, laptops, portable MP3 players, cell phones, torch lights, transistor radios, TV / AC / Video player – remotes and in most toys that your child plays with.  They surround you everywhere and perhaps a life without them is unimaginable.  A battery in someway is a can full of chemicals that produce electrons.  They come in various shapes – cylindrical,
prismatic/rectangular, power packs, coins, lithium button cells and more. An AA battery is a standard size of battery.  The AA battery size was standardized by ANSI in 1947  - traders say that these batteries account for the high % of their battery sales.    For most purposes, we use AA batteries  - there are some popular brands in India and that includes – Eveready, Toshiba, Maxell, Sony, Duracell …… does this ring a bell in you ? 

As you would have noticed all batteries have two terminals – a  zinc-carbon dry cell or battery is packaged in a zinc can that serves as both a container and negative terminal.  The positive terminal is a carbon rod surrounded by a mixture of manganese dioxide and carbon powder . Zinc-carbon batteries are the least expensive primary batteries and thus a popular choice by manufacturers when devices are sold with batteries included. They are commonly labeled as "General Purpose" batteries. They were the first commercial dry battery and made things such as flashlights and other portable devices possible, because the battery can function in any position.

This is the way the batteries work  : An electrical battery is one or more electrochemical cells that convert stored chemical energy into electrical energy.[   Electrons collect on the negative terminal of the battery. If you connect a wire between the negative and positive terminals, the electrons will flow from the negative to the positive terminal as fast as they can and wear out the battery very quickly -- this also tends to be dangerous, especially with large batteries.  There has to be some load to the battery using the wire. The load might be something like a light bulb, a motor or an electronic circuit like a radio.   Inside the battery, a chemical reaction produces the electrons. Electrons flow from the battery into a wire, and must travel from the negative to the positive terminal for the chemical reaction to take place. That is why a battery can sit on a shelf for a year and still have plenty of power -- unless electrons are flowing from the negative to the positive terminal, the chemical reaction does not take place. Once you connect a wire, the reaction starts.

There are two types of batteries: primary batteries (disposable batteries), which are designed to be used once and discarded, and secondary batteries (rechargeable batteries), which are designed to be recharged and used multiple times.  When you are using a disposable battery, the costs could be high and you need to have more back ups.  People preferred alkaline batteries as they had a longer shelf life and higher energy density – but also was costlier.   The advantage with rechargeable batteries is that after the initial investment, you just recharge them by placing them holder, connect to a electric point and after some hours, they are ready for use till they discharge their power.  This is extremely cost effective and comes handy as the batteries can charged whilst you are on tour or elsewhere, provided you have an electric power supply. 

There were problems still – unlike primary batteries, these would get discharged on their if not in use and if the charge was given a few days earlier, they may not retain the power – when you actually want to use them.  Thus you might be left high and dry with no power on the important occasion when you want to hear your favourite melody or want to take photos of a grand occasion or when you switch on your torchlight in pitch darkness !!  In any rechargeable battery, by putting them on charge, they can be used multiple times.  Once charged they lose their energy rather quickly, so frequent re-charging or charging just before usage becomes necessary.

Could there not be a via-media option which combines the advantages of rechargeable batteries with the advantages of disposable batteries.  Recently I discovered it [it has been in vogue for long – only that I was presented a set of such batteries by my BIL recently]  These are the batteries developed by SANYO and launched in European market in 2006.  This is known as ‘eneloop’ batteries.  These are  low self-discharge nickel-metal hydride battery (LSD NiMH)  which reduces self-discharge and, therefore, lengthens shelf life compared to normal NiMH batteries. Low self-discharge cells are marketed as "ready-to-use" or "pre-charged" rechargeables. Low self-discharge NiMH batteries are good for photography and other high energy requirement applications.  Aside from their longer shelf life and moderately higher prices, they are otherwise similar to normal NiMH batteries of equivalent capacity and can be charged with normal NiMH chargers.

SANYO claims that their eneloop batteries can be recharged upto 1500 times and the generation of make can be seen by checking the model name.   The "old" cells have written HR-3UTG (AA) and HR-4UTG (AAA) on them, the improved eneloop instead HR-3UTGA (AA) and HR-4UTGA (AAA).   These eneloop batteries are of 1.2 V and they claim that they will remain up to 75% charged if not used for up to 3 years.  A tall claim indeed.  Another advantage is that they use Nickel Metal Hydride; are not lithium and therefore do not fall under the new travel regulations for lithium batteries.  Most NiMh rechargeable battery chargers may be used to charge eneloop, however  the Manufacturers prefer it to be used with an eneloop, Sanyo or Sanyo NiMh battery charger.  It is also recommended that the battery be left with some charge so that the overall life would stand better. 

I have tried and found eneloop to be too useful.  There are ofcourse similar ones from the stables of Fujicell, Sony, Kodak, Duracell and more. 

Eveready is a household name in Indian market –  since 1905.  The Group set up its first battery plant in Calcutta in 1939 and then in Chennai in 1952.  A torch manufacturing plant was set up at Lucknow in 1958. In 1969, the now infamous factory in Bhopal was opened.  The Bhopal Gas tragedy, an industrial catastrophe occurred on the night of Dec 2/3 of 1984 at this Union  Carbide India Limited (UCIL) pesticide plant in Bhopal.   A leak of methyl isocyanate gas and other chemicals from the plant resulted in the exposure of hundreds of thousands of people. After more than 25 years, the victims are yet to get just compensation is a sad story.

Regards – S. Sampathkumar.


  1. Nice compilation on LSD NiMH batteries and Sanyo Eneloop which can help to further spread awareness about this clean/green and cost effective technology in India. One barrier could the relative higher initial cost but RoI over time can more than justify it. Indeed Sanyo is a technology leader in this space, and interestingly the Eneloop batteries continue to be made in Japan. The Eneloop XX AA battery released last year comes with a capacity of 2500mAH (the usual Eneloop AA being 2000mAH). One wonders why mobile phones don't use these LSD NiMH batteries as the typical Lithium Ion batteries used in mobile phones is only around 1000-15000 mAH!

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