This page was a price list

The legacy version of this page published a price list. Prices are not reproduced here: brief §30 requires commercial data to come from supplied current sources, and the legacy figures carried no validity date. Send us your requirement for a current quotation.

How the battery is sized

The load in watts that the UPS must carry

The autonomy required in minutes or hours

The battery voltage and the number of blocks in the string

The end-of-discharge voltage and the inverter efficiency

The ambient temperature, since capacity is quoted at 25 °C and falls as temperature rises

Why the nameplate capacity is not the delivered capacity

Battery capacity is quoted at a specific discharge rate. Discharging a battery quickly delivers less energy than discharging it slowly, so the same block gives different autonomy at different loads. The manufacturer’s discharge tables, not a simple division, give the honest figure.

When to replace

Measured capacity below the acceptable proportion of rated capacity

A cell or block that diverges from the rest of the string

Physical signs: swelling, terminal corrosion, case damage

Age, since VRLA blocks have a design life that heat shortens considerably

Replacement practice

Blocks are replaced as a set. Replacing one block in an aged string leaves the new block to carry more than its share and shortens its life.