What Are Solar Power Batteries?

Affordable solar power batteries are essential if you need to store enough surplus solar electricity to get you through several days of cloudy, overcast weather, or to even get you through the nighttime hours. However, it's essential that you get the proper type of battery. Read below to learn what's needed.


Types of Deep Cycle Storage Battery

Deep Cycle Storage BatteryDeep Cycle PV Storage Battery
(Source: ©Don Bell)

Affordable solar power batteries are essential if you need to store enough surplus solar electricity to get you through several days of cloudy, overcast weather, or to even get you through the nighttime hours.

There are two basic kinds of specialized storage batteries used in photovoltaic (PV) systems:

  • Lead acid batteries

  • Nickel cadmium batteries

We'll compare them in this article.

Lead Acid Storage Batteries

Lead acid batteries are by far the most common battery used in PV systems, chiefly because of their lower cost. They are somewhat similar to the familiar lead acid car battery with positive and negative terminals with leads attached, and metal plates that connect to the terminal. The metal plates sit in a chemical solution inside the battery case, usually sulfuric acid.

The chemical reaction between the lead plates and the sulphuric acid generates free electrons that flow through the terminals and along the attached leads to your home electrical outlets. Conversely, during the hours of sunlight, electricity generated by the photovoltaic (PV) panels drives the chemical reaction backwards, thereby recharging the batteries.

Nickel Cadmium Storage Batteries

Commonly called NiCd or NiCad batteries, these solar rechargeable batteries operate under the same principles as lead acid batteries with some important differences.

First, they are significantly more expensive to buy because of their use of costlier materials, nickel and cadmium. However, they tend to deliver greater long-term value by being able to endure more charge/discharge cycles and lasting much longer, and they can discharge more current before needing to be recharged.

If your budget permits, choose NiCad over lead acid when buying a storage battery, but the cheaper lead acid variety is perfectly reliable if cost is a concern.

Solar Power Batteries versus Car Batteries

The common lead acid car battery is known as a "shallow cycle" battery, since it's designed to supply a large amount of current for a short time for starting the car. Once the car has started and its engine is running, the alternator takes over to power the car's electrical needs and to quickly recharge the battery.

Their quick discharge rate makes them unfit for delivering surplus solar power to your home electrical outlets, so they should NEVER be used in a PV system installation.

While solar power storage batteries might look like car batteries, they are designed to respond to a different need. They need to deliver a smaller current over a much longer time period.

Known as "deep cycle" batteries, they efficiently discharge during the night hours when the photovoltaic panels cannot deliver electricity to power the home or to recharge the storage batteries, and they slowly recharge during the day using the electricity produced by the solar panels.

Battery Charge Controller

The lead acid and nickel cadmium type of batteries commonly used in PV systems are both "deep cycle" batteries. They are designed to charge and discharge slowly and can last 6 to 10 years if they are properly used and maintained with the help of a solar charge controller.

Charge controllers help to regulate the flow of electricity to and from your solar power batteries to prevent their over charging/discharging and thereby maximize their service lifespan.

Follow the link below for more information about battery charge regulators:

How to Prolong Battery Life with a Solar Charge Controller

See More Information about Solar Battery Storage







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