As well as the various types of battery construction, there is a wide range of different chemicals used in the different types of cell. Below is a general comparison table for the different battery types. If you wish to find out more about the science behind the various technologies, please see The Science of Batteries section.

Comparison Table

This table provides a quick reference guide to the various battery technologies available. For more information on why certain batteries are better for various applications see Applications below.

Applications

Portable Audio Equipment

The batteries you choose to use in devices such as Walkmans and CD players depend on how often you use them.

If you use them regularly, i.e. daily, then it is advisable to use rechargeable NiMH batteries. They will need to be charged quite regularly but in the long run will last longer than your standard alkaline primary battery.

If you use your device occasionally then it would be better to use standard alkaline batteries. This is because of the low self discharge rates, compared with NiMH batteries. It means that if you leave your device idle for extended periods, the battery will have sufficient power to continue to run your device.

Portable digital devices

These include devices like Camcorders/Cameras/Digital Cameras/Laptops which require large amounts of power to operate.

Secondary batteries such as Lithium-Ion and NiMH are most suited to these devices. Lithium-Ion batteries are much more expensive than NiMH mainly because they are more robust and offer higher cell voltage than NiMH (3v per cell as apposed to 1.2v). Generally, the manufacturer of the device you are using will specify which type of battery is to be used in it.

As with any device which uses rechargeable batteries, it is best if you use your device regularly. They do not hold their capacity well (Lithium Ion is slightly better than NiMH) so if they are left idle then they will not be able to power your device. It is important to charge your batteries before initial use and if they have been left for extended periods.

Watches/Hearing Aids

on cells are the most common type of battery used for these devices. The type used will be listed in the operating instructions so your choice is limited to what the manufacturer specifies.

With Hearing Aid batteries, the amount you use the hearing aid will vary the length of time that your battery lasts in it. If you use it a lot then make this known to your hearing aid manufacturer and they will advise you on the best Hearing Aid for you.

Most if not all Hearing aid batteries use Zinc Air technology:

• These batteries come with a plastic tag attached to them.
• Once this is removed then it becomes activated and will not work until this is removed,
• Do not remove this tag until you are ready to use the battery, if it is stored like this then it will self discharge at a high rate and you may find that it won't work when you come to using it or It will not last as long as you expected.

Cordless Phones

Again the battery used in your cordless phone will be specified by your manufacturer; however there are a few things to note about Cordless Phone batteries:

• There are a wide range of connectors used on these batteries; when you come to replacing your battery make sure you tell the supplier the make and model of your phone as well as the including the battery code and size, this will make it easier for the company to find the right replacement battery.
• · You will need to charge your new cordless phone battery for up to 24 hours before its first use.
  It is advisable to occasionally completely discharge your battery in order to restore the original capacity and discharge behaviour. (This is less important with NiMH and Lithium Ion; it is NiCd batteries which suffer greatest from partial discharge cycles. For more information see Memory Effect)

Stand-by power applications

Sealed lead acid batteries are ideal for stand by application, be it alarms, emergency lighting, UPS (Uninterrupted Power Supplies). Because they are sealed, they ensure no electrolyte leakage from the casing or terminals.

Compared to other lead-acid batteries, they have superior ability to recover from deep discharge†. They can last either 5/10/20 years depending on cost in stand-by (float*) use. However they to provide between 100 - 1000 charge/discharge cycles, depending on the depth of discharge.

†Deep Discharge: Rechargeable batteries have an 'end-of-discharge' voltage; this voltage level varies for each battery type. At this voltage level, roughly 99% of the energy of the battery is spent and the voltage starts to drop rapidly if the discharge continued. Deep discharging is where the discharge cycle continues past this cut-off voltage, this can damage the battery, possibly irreversibly if discharging continues for too long. For more information see our Discharging section.

*Float: is a term used in reference to charging of the battery. When batteries are used for backup power applications, they are often left on constant trickle charge at a very low rate. The rate of this charge is only slightly greater than the batteries self discharge rate.