Stationary batteries come in a wide variety of designs for different applications. They are used for applications where power is necessary only on a standby or emergency basis. Stationary batteries are infrequently discharged. Stationary batteries remain on a continuous float charge so that they can be used on demand. The largest types of stationary batteries are those used for electrical load leveling. Load-leveling batteries store electrical energy for times of peak power demand and are taken off-line during times of low power demand. Stationary batteries are also used for backup emergency power, telecommunications equipment, and uninterruptible power supplies. Stationary batteries are manufactured in a variety of plate designs. An example of a stationary battery used for backup power is shown in Figure 13.

Portable

Portable lead-acid batteries are usually of the sealed type constructed similarly to that depicted in Figure 14. Their operation cannot usually be described as cyclic or float, but is somewhere in-between. Batteries in this category may be frequently deep cycled or remain unused for a relatively long time. Typical applications are portable tools, toys, lighting and emergency lighting, radio equipment, and alarm systems. Most portable batteries may be recharged to 80-90% of their original capacity in less than an hour using a constant-voltage charger.

Figure 13. Typical stationary battery used for backup power.

Figure 14. Components of sealed lead-acid cell.