Home >> Science & Nature >> Science

How Long Do Batteries Last in Storage?

The lifetime of a battery in storage strongly depends on its chemistry and construction. Commonly available alkaline types can sit on a shelf up to 10 years with little loss in power. On the other hand, many rechargeable batteries hold up only a few months. Heat and other conditions also influence how well batteries survive long-term storage.

Self Discharge
- Self-discharge is the phenomenon in which chemical reactions occur in a battery that̵7;s not connected to a circuit; the reactions create an internal resistance that slowly uses up the battery̵7;s energy. All battery chemistries are subject to self-discharge, although some last longer than others. For example, lithium-metal primary batteries have among the lowest rates of self-discharge, losing only 10 percent of their energy in 5 years. Alkaline batteries also have good shelf lives, having a self-discharge rate of about 3 percent per year. Nickel-metal hydride rechargeable batteries, on the other hand, self-discharge relatively quickly; they can lose up to 15 percent in the first 24 hours after charging, then another 15 percent for each month that follows.
Leakage
- Carbon-zinc batteries, an older battery technology, have a tendency to leak their electrolyte; while powering a device, the electrolyte consumed the zinc outer case, eventually perforating it and allowing the semi-liquid insides to leak out. Although alkaline batteries have a different construction than carbon-zinc types, they also have problems with leakage. Rechargeable batteries are much less prone to leaking, but if improperly charged, their cases might break, causing the batteries to leak.
Storage Temperature
- Chemicals tend to react faster at higher temperatures, so excessively hot conditions speed up self-discharge and reduce a battery̵7;s storage life. For example, a lead-acid battery stored for a year at 40C has 62 percent of its charge left; at 0C, this figure improves to 97 percent. Cool temperatures maximize storage life although you must avoid very cold conditions, as freezing can damage batteries.
Trickle Charging
- Because a lead-acid battery self-discharges relatively rapidly, it helps to connect it to a trickle charger when the battery is unused for long periods. A trickle charger passes a small amount of current through the battery at the proper voltage, reversing the effects of self-discharge. For example, if you ride a motorcycle during warm months and store it for the winter, keeping the battery on a trickle charger ensures that it will be ready when spring arrives.

Science