[VIDEO] How many battery cells for an inverter?

A common question we are asked is “What battery should I use for this inverter?” The reality is, most inverters will tell you just from the model number.

Liteplan for instance, drop the number of cells into their model numbering system as follows:
T5 inverters
HRN/T5/4/21+22 (use a 4-cell battery)
HRN/T5/6/35+49 (use a 6-cell battery)
T8 inverters
HRN/3 (use a 3-cell battery)
HRN/4 (use a 4-cell battery)
HRN/5 (use a 5-cell battery)

Tridonic have it as the last number shown after the hyphen in their code:
T5 COMBO Ballasts
PC 1×14-3 T5 COMBO lp (use a 3-cell battery)
PC 2×54-6 T5 COMBO lp (use a 6-cell battery)
T8 COMBO Ballasts
PC 1×36-33 COMBO (use a 3-cell battery)
PC 2×58-34 COMBO (use a 4-cell battery)
CFL COMBO Ballasts
PC 2×18-4 TC COMBO (use a 4-cell battery)
PC 1×38-34 LO DD COMBO (use a 4-cell battery)
*The green number denotes the number of hour’s emergency (i.e. 3hr emergency)

Some final points to note on batteries:
1. Inverters will usually say on the sticker how many volts the battery should be. Typically, each cell is 1.2V so a 4.8V would be 4-cell.
2. Often, T5 batteries are NiMH, or LA-cell, which are smaller in diameter than the traditional D-cell used more commonly in T8 fluorescent or compact fluorescent. Whilst they look different, the number of cells will be the same.
3. Batteries can be in stick or side-by-side formation. This makes no difference to the functioning of the battery but space in the luminaire will often dictate what configuration will fit.