NiCad (Nickel Cadmium) - This is the oldest technology and is the least commonly used nowadays. NiCad batteries are prone to the “Memory effect" and are heavier than the newer technologies. NiCad is not environmentally friendly chemistry as it contains heavy metals, which cannot be disposed of in landfill sites. Most manufacturers have stopped producing batteries of this type chemistry. As an end user it will be increasingly difficult to source these batteries. The best alternative is external battery packs. This is an external battery, with run times of up-to 10hours and is compatible with most manufacturers.

NiMH (Nickel Metal Hydride) - These batteries are less likely to be prone to the memory effect and have a much better power to weight ratio than NiCad. This is a commonly used chemistry. These batteries are also being phased out by most manufacturers. However, many have lithium-ion versions that are compatible. Always consult the manufacturer or a reputable laptop battery supplier.

Li-Ion (Lithium Ion) - This is becoming the dominant technology due to its excellent power to weight ratio. Such considerations are becoming more important as mobile devices become smaller and lighter and battery weight becomes significant. Another plus point for Li-Ion is that it doesn't suffer the memory effect at all. These batteries do have a tendency to lose charge quickly towards the end of their effective life span. If this starts to happen the battery must be replaced.

These three technologies are quite different in the way they charge and therefore should not be substituted unless the device has been designed to take different chemistries. The owner's manual will describe which batteries are suitableLithium Ion laptop batteries are available at ComputerBatteries.co.uk



Laptop Battery Capacity

Laptop batteries are rated by, Voltage (V) and Milliamp-hours (mAh). Voltage is the rate at which energy is drawn from the battery and Milliamp-hours represents the capacity of the battery. The Milliamp-hour rating corresponds to the run time of the battery. A battery with a high Milliamp-hour rating, has a relatively longer run time than a battery with a low Milliamp-hour rating.

Batteries with different Milliamp-hours can be used on the same laptop provided the voltage rating is the same. The voltage rating has to match that of the original battery or as recommended by the computer manual. Using a battery with a different voltage setting can seriously damage the laptop. The power ratings of most compatible/replacment batteries are higher than the original manufacturers' batteries. This will not damage your laptop, in fact, it simply means that these batteries in many cases last longer than original manufacturers' batteries. Ask the experts like PowerUp on compatible replacement laptop batteries.

The run time of a laptop battery will vary on individual notebook computers, based on the applications being used (i.e. high graphics, games), the number of times something is saved or retrieved from the hard drive and/or CD Rom drive, the memory of notebook, and chemistry and capacity of the battery. A ‘realistic’ average run-time for a battery is 1.5 to 3 hours. Using devices like a wireless adapter on the laptop also drains the battery considerably.

The life of a battery under normal use is around 500 to 900 charge-discharge cycles. This is about one and a half to three years of battery life for the average user. As the rechargeable battery begins to fail, the running time of the battery begins to decline. See the Laptop Battery & AC Adapter Information page for advice from PowerUP.

Laptop Battery Care

Most laptop batteries when purchased, are sent out in a discharged state. The laptop batteries require to be "run them in" to achieve maximum performance and the best service life. Simply insert the battery into your laptop and allow it to charge fully and then, fully discharge your battery (i.e. run your laptop using battery power until it switches off) then fully charge your battery once again.

It is possible that when you first put the new battery into your laptop it will show it is fully charged almost straight away, but it doesn't power the laptop for very long. This does not mean the battery is faulty, simply take out and reinsert the battery, fully charge it once again and this should solve the problem.

It may take some time for certain laptops to recognise new batteries and you may have to run a calibration program that you can access through the control panel on your laptop. If in any doubt please consult your users manual for your laptop.

Make sure that you fully discharge your battery from time to time, as this will prolong the useful service life of the battery. If you are not going to use the battery for some time (perhaps a month or more), remove it from your laptop in a fully charged state and store it in a cool dry place away from sources of heat and light.

Listed below are tips to ensure optimal battery life:

•Use the AC adapter whenever possible.
•Set the Windows Power Management settings to maximum savings.
•Lower the brightness setting on the screen backlight.
•Disconnect any unused devices (e.g., modems) when not needed.
•Use power management freeware like Power Center 2.12.
•Disable Auto Insert Notification on the CD-ROM.
•Turn off Autosave features.
•Disable automatic formatters, spell checkers, and autorecalculate features.
•Use disk caching programs such as Norton Utilities to lower disk access time.
•Add RAM to lower disk access time.
•If you have a backup battery, use it in rotation with the current battery.
•Use the Suspend or Hibernate feature when taking a break.
•Fully drain and recharge the battery every couple of months.
•Minimize the number of programs running at the same time.
•Use smaller programs when possible (e.g., WordPad versus Word).
•Minimize game play and DVD viewing.