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Technology improvements in battery chargers over the years have improved the speed of charging. However, some rapid chargers may cause damage to the rechargeable battery:

“The recharging rate has improved substantially over the years and is broken down into three categories:
· Slow: 14-16 hours
· Quick: 3-6 hours
· Fast: Less than one hour

The rate of charge is determined by how much electrical current is allowed into the battery by the charger. Some batteries can handle higher voltage in a shorter amount of time without overheating, while others need a lesser voltage applied over a longer period of time. The quicker the rate of charge, the more chance there is of over charging, which can ruin a battery’s chance of holding its charge. The key in avoiding an over charge is the ability to dissipate the charging current once maximum power has been reached. Most chargers have built-in voltage regulators do this, allowing you to safely leave your cell phone or computer plugged in overnight.

The speed and effectiveness of the charge depends largely on the quality of the charger itself. Chargers vary in performance based on the price tag and like most products you get what you pay for. Chargers are generally designed for specific cell chemistry, although newer universal chargers have sensors built in, that identify the cell type and react appropriately. There are also smart chargers that use a microprocessor to monitor temperature, voltage and state of charge, which is the percentage of power available compared to its full capacity.”

“The energy used to charge rechargeable batteries mostly comes from AC current (mains electricity) using an adapter unit. Most battery chargers can take several hours to charge a battery. Most batteries can be charged in far less time than the most common simple battery chargers are capable of. Duracell and Rayovac now sell chargers that can charge AA- and AAA-size NiMH batteries in just 15 minutes; Energizer sells chargers that can additionally charge C/D-size and 9V NiMH batteries. However, high rates of charging (eg. 15 minute charger, 1 hour chargers) will cause long term damage to NiMH and most other rechargeable batteries.”

Sources:

(i) How Batteries Work: Rechargeable Batteries
Website: HowStuffWorks – Learn How Everything Works!
URL: http://www.howstuffworks.com/
Direct URL: >>http://electronics.howstuffworks.com/battery4.htm

(ii) Rechargeable battery
Website: Wikipedia, the free encyclopedia
URL: http://en.wikipedia.org/wiki/Main_Page
Direct URL: >>http://en.wikipedia.org/wiki/Rechargeable_battery

All websites were last accessed on 15/8/2009.

You may also wish to refer to the following books for more information on batteries:

(i) Title: Battery operated devices and systems : from portable electronics to industrial products / G. Pistoia.
Publisher: Amsterdam ; Singapore : Elsevier, 2009.
Call No.: R English 621.31242 PIS
(For reference only at the Lee Kong Chian Reference Library)

(ii) Title: Handbook of batteries / David Linden, editor, Thomas B. Reddy, editor.
Publisher: New York : McGraw-Hill, 2002.
Call No.: R English 621.31242 HAN

To check the availability of the titles, please visit the online catalogue at: http://catalogue.nlb.gov.sg

Answered by Ms Lynn Koh, Librarian, Adult and Young People’s Services

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