BATTERY POWER TO ENHANCE SOLAR
The battery you choose to capture the solar energy from your system is important. Solar panels only allow for power when there is sunlight – so what happens when the sun goes down. Battery or batteries are needed to ensure power is provided to your devices/appliances/lights etc as and when needed at night. Solar-generated electricity charges the batteries during the day, usually through a charge controller. In a grid-backup or enhanced self-consumption solar PV system, there are two types of battery commonly chosen – Lead-Acid or Lithium-Ion.
There are many factors that influence the life cycle of a battery so it’s almost impossible to estimate how long a given battery will last. These factors include battery type, the number of charging/recharging cycles, operating conditions, like temperature, and how fully the battery was discharged, among others.
There are a number of good batteries on the market but they are not always in stock due to high demand. We stick to the brands and suppliers we know are reliable, have good after-sales support and offer solid warranties. Be aware that not all batteries on the market do what they say they do. There are a number of poor-quality knock-off products on the market, so be cautious if a battery seems too cheap as it shouldn’t be.
Lithium-Ion
Lithium-ion batteries are built on much newer technology and are low maintenance. Their biggest advantage is their significantly improved lifespan, with faster charge and discharge times across their capacities.
They have an improved depth of discharge * and lose less capacity due to irregular discharging. They are light, compact, easy to install and easier to dispose of.
They perform well both in colder and hotter temperatures. But they cost much more upfront than lead-acid. The longer lifecycle of this battery means that despite a higher initial investment, the battery will cost less over its lifecycle.
Lithium-ion batteries can also charge much faster at higher voltages. While it can take lead-acid batteries up to 16 hours to fully charge, even the slowest charging lithium-ion batteries can fully charge within about four hours.
* A battery’s depth of discharge (DoD) indicates the percentage of the battery that has been discharged relative to the overall capacity of the battery.
Lead-Acid
Lead-acid batteries have been used to provide backup power for solar homes since the 1970s. While they’re similar to conventional car batteries, the batteries used for home energy storage are called deep-cycle batteries since they can be discharged and recharged to greater levels than the batteries in most cars and trucks.
Lead-acid batteries are significantly cheaper upfront than lithium-ion. They are robust, resilient and reliable. Lead-acid batteries can be discharged up to 50 percent of total capacity without any repercussions.
One major downfall of the lead-acid solar battery is that its power capacity drops significantly in colder temperatures. Additionally, they are big, bulky and difficult to maintain.