There are four different types of emergency lighting batteries. These are:
- Sealed Lead Acid (SLA)
- Nickel Cadmium (NiCd)
- Nickel Metal Hydride (NiMH)
- Lithium-ion Phosphate (Life PO4)
Sealed Lead Acid
These are typically larger batteries used in ‘high-drain’ applications such as emergency twinspot luminaires or multiple lamp battery systems.
Whilst becoming less popular, these are still a very common battery coming mainly in D-cell or C-cell size. They are typically used in older technology compact fluorescent and T8 linear fluorescent luminaires.
Nickel Metal Hydride
The smaller size of the NiMH battery (typically AA-cell size) makes it ideal for limited space applications such as T5 linear fluorescent as well as many LED luminaires.
A relatively new technology, LED luminaires in current production are now starting to use this technology. They have a life over double that of other technologies (typically 8 years), cope will in harsher environments (i.e. freezer lighting) and are heavy duty.
When specifying a battery ensure you give the following information:
- Which of the above battery types is it?
- This will be on the battery but if you are struggling to read it, you can also be reasonably certain that each cell will be 1.2V so a 3-cell battery would be 3.6V.
- Amp-hour rating. This is the capacity of the battery which is relative to how long it will last.
- Is it in a stick configuration or are the cells side by side?
- Connections/terminals. There are many different types such as fly-leads or spade terminals.
- Any other details. Some batteries may be in an intumescent sleeve, some may be mounted on a plate, or in a triangular bundle.
- As always, an image of the battery and the label is excellent if it can be given.
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