A battery backup device is important for keeping your computer systems powered if there is a power failure. The devices also function as power conditioners and ensure that the electricity flowing to your equipment is free of drops and surges.

Home energy-storage batteries are becoming increasingly popular as homeowners look to reduce their carbon footprint and protect against power outages. Learn more about the different options available for home battery backup.

Rechargeable Batteries

Rechargeable batteries have a reversible chemical reaction that lets them recharge. They can be used hundreds or even thousands of times, which is much better for our environment than throwing away disposables.

Small rechargeable batteries power portable electronics and cordless power tools, while heavy-duty batteries are used in electric vehicles and off-grid and supplemental facility power storage. They are also used for load-leveling at power plants to reduce the need for expensive peaking facilities.

These nickel-metal hydride (NiMH) batteries are great for energy-sucking devices like digital cameras and studio equipment, as well as remote-controlled toys and microphones. They have a high charging cycle lifespan and hold a charge for long periods of time, but they do lose their charge over time in storage. For this reason, it is best to buy the low self-discharge version of these batteries if you need them for storage. They cost more upfront, but you'll save in the long run.

Lithium-Ion Batteries

Despite using less toxic metals than lead or nickel-cadmium, lithium is still a hazard and must be handled carefully. Most lithium batteries use a protection circuit that limits the peak voltage during charge and prevents the cell from discharging too low on discharge.

They also have a low self-discharge rate, allowing them to retain their full capacity over longer periods of time. Lithium-ion batteries are also low maintenance and do not require scheduled cycling to prolong battery life.

UPS manufacturers use lithium-ion batteries in their products to support critical functions for an appropriate amount of time during a power outage or fluctuation. This makes them a great choice for businesses that want to guarantee a consistent power supply to vital office equipment, medical or health care facilities that need to keep running, and electric vehicles that must be driven consistently. You can identify which devices have lithium batteries in them by looking for the chemistry listed in the product documentation, instruction manual or by an icon or symbol that indicates the battery chemistry.

Lead-Acid Batteries

Lead-acid batteries are the oldest rechargeable battery technology. They are inexpensive and have a high power-to-weight ratio, making them the go-to choice for starting engines and lights. However, they are not ideal for long run times or deep cycling. Consequently, they are not the best option for off-grid solar applications.

A lead-acid battery consists of an anode (lead plates) and a cathode (lead dioxide). These are separated by an electrolyte, a solution of sulfuric acid and water. The battery stores energy through the reversible chemical process of lead oxidation and dissolution.

Batteries that are flooded with a mixture of sulfuric acid and distilled water are referred to as flooded batteries. These need to be placed upright to prevent leaking and they must be periodically watered with distilled water. Batteries with the electrolyte absorbed into a separator or in gel are known as sealed or maintenancefree lead-acid batteries, and do not require regular watering. They are able to withstand more stress during charging and discharging, but their cycle life is less than that of a flooded battery.

Nickel-Cadmium Batteries

Nickel-cadmium batteries (NiCd) used to be popular for notebook computers and personal digital assistants, but their lifespan is now limited by the availability of cheaper, rechargeable lithium-ion alternatives. Still, NiCd batteries remain in use for emergency lighting and uninterruptible power supplies.

Like other rechargeable batteries, nickel-cadmium cells require proper charging and maintenance to function properly. Mistreating a solar battery, even once, can significantly shorten its life.

In its charged state, a NiCd cell consists of positive and negative plates, separators, an electrolyte and a cell vent. The positive plates have a porous plaque on which nickel-hydroxide has been deposited, and the negative plates have cadmium oxide and cadmium metal as active materials.

Unlike lead-acid batteries, nickel-cadmium batteries do not contain sulphuric acid. However, the alkaline electrolyte they use contains potassium hydroxide, which can irritate skin and eyes. For this reason, a separate storage and maintenance area should be provided for nickel-cadmium batteries. Also, any equipment used for working with lead-acid batteries should be kept well away from the nickel-cadmium shop to prevent contamination of the electrolyte.