Truth about solar battery explosion danger

Most modern lithium batteries used in solar power systems in South Africa are highly unlikely to explode or catch fire.

However, owners of these devices should ensure they are installed by qualified people and operated according to sound safety principles.

As the adoption of lithium technology has surged in the past few years, stories of battery “explosions” have often made news headlines.

These batteries have a high energy density packed into a confined space.

If their stored energy is released in an uncontrolled manner, it can cause a process called thermal runaway, releasing gasses which can ignite flammable materials inside and around the battery.

One recent major battery malfunction in South Africa occurred at the home of Jacques and Annetjie Venter in Vanderbijlpark in early January 2025.

The couple, their son, and three guests were injured when a stored lithium battery that had been disconnected from their solar system exploded.

The family’s insurance company and the solar system installer told the victims that the issue was caused by chemical degradation — a one-in-a-million problem.

Considering that billions of lithium batteries are in operation worldwide, the likelihood of such an incident is quite low, relatively speaking.

It is not necessarily the frequency but the unusual intensity and length of lithium battery fires and the severity of the damage they can cause that captures the public’s attention.

While there has been much fear-mongering about the dangers of lithium battery-equipped electric vehicles (EVs), studies have shown that petrol and diesel cars are far more likely to catch fire than EVs.

Prominent Cape Town-based solar power installer AWPower addressed the issue of battery safety following a spate of incidents in South Africa’s solar adoption surge in 2023.

The company said it was important to note that nearly all lithium batteries used in solar system applications in South Africa were lithium-iron phosphate (LiFePO4) batteries.

“This type of lithium-ion battery is one of the most stable lithium batteries, and it is highly unlikely — although not impossible — that they will experience thermal runaway,” AWPower said.

“One can argue that an installation using old lead-acid batteries is more dangerous than an installation with LiFePO4 batteries.”

The company said there were typically four causes of thermal runaway:

• Internal short circuits — Physical damage or manufacturing defects can cause internal short circuits.
• Overcharging and over-discharging — Exceeding the recommended charging or discharging rates can lead to dangerous conditions.
• External heat sources — Batteries exposed to high ambient temperatures or placed near heat-generating devices are at risk.
• Age and wear and tear — Over time, batteries naturally degrade, which can increase the risk of failure.

Although a malfunction can never be completely ruled out, there are some steps households and businesses with backup batteries can take to minimise the chances of a major mishap.

AWPower repaired many systems in 2024 installed by inexperienced teams that were not suitably qualified and certified.

The installer said it was vital that lithium battery systems were installed and tested by suitably trained and certified technicians.

“The installation must adhere to all relevant legislation as well as manufacturer guidelines,” AWPower advised.

“A valid electrical Certificate of Compliance (CoC) and a test report for the system must be issued and available for inspection.”

“This ensures that the installation meets all safety standards and regulations. Proper installation not only ensures the system operates efficiently but also significantly reduces the risk of fire.”

AWPower said one common mistake was insufficient spacing between the inverter and battery, which could lead to overheating and fires.

Another frequently recurring mistake was the use of incorrectly sized wires, with inadequate or no fusing or circuit breakers, causing overheating and melting.

“Loose or improper electrical connections are also a large contributor to electrical fires,” it added.

AWPower recommended that battery owners arrange for regular inspections and maintenance to identify and mitigate potential risks.

“Schedule regular checks with your solar partner to ensure all components are functioning correctly and safely, further to ensure that no connections come loose over time,” the installer said.

“If you are a landlord, ensure your tenants are aware of the dangers and requirements related to these systems. Failure to do so may result in insurance claims being repudiated.”

Lastly, AwPower advised against storing combustible materials within two meters of any inverter or battery.

Major South African lithium battery manufacturer Freedom Won recently also told MyBroadband that the risk of thermal runaway was low as long as the installation complied with the technical electrical requirements.

The company said it had actually seen more instances of inverters malfunctioning than batteries.

Freedom Won advised installing systems in garages where possible, as these are generally designed as fire-proof rooms.