With the coming of the multimedia age, the maintenance of storage batteries used in information technology devices is taking on increased importance. The 3550 series of Battery HiTesters are able to give instantaneous results on the state of a battery, on a three-rank scale of Pass, Warning, or Fail, using a composite decision based on the internal resistance and the voltage. To the existing models 3550, for medium-capacity alkali and leadacid storage batteries, and 3555, for compact storage batteries, a new model, the 3551, is now added to support high-capacity alkali and lead-acid storage batteries. These three models will now meet battery maintenance requirements across a wide range of applications.

With repeated charging and discharging of a storage battery over a long interval, the battery performance gradually deteriorates, and the internal resistance increases until charging is no longer possible. Faults may also be caused by internal short-circuits, reducing the battery voltage, making the battery over-heat, or even in the case of a short-circuit caused by corrosion, leading to a fire.

The 3551 is able to give instantaneous results on the state of a battery, on a three-rank scale of Pass, Warning, or Fail, using a composite decision based on the internal resistance and the voltage. The 3550/3551 Battery HiTester takes on-the-spot measurements of the internal resistance and voltage of lead-acid batteries, principally for UPS and similar applications. It then without needing to shut off the battery.