Causes of Solar Panel Fires, Battery Explosions, and Burning Inverters — Prevention and Safety Guide

There are cases of explosions and fire outbreak due to solar power installations. Despite the exponentially number of solar installations (about 0.2 MW to 1.5 MW or 150 to 400 daily installations in Nigeria and 1.8 GW to 2.1 GW or 10,000 to 15,000 installations globally), and the extremely rare chances of solar fire outbreak happening, which is at about about 0.01% or 1 in 10,000 installations, it is still worthwhile to know the potential hazards that can led to this unfortunate fiery experience and prevent its likelihood.

Videos of solar panels on fire, burning buildings as a result of solar installation, inverter fire or battery explosion always trend on social media whenever it happens, and it sticks as a living-day nightmare to people that have solar energy systems in their home, as well as potential owners.

This have led to many wrongly concluding that solar panels should not be mounted on rooftops, and that a separate stand such as carports should be contructed for it. It has also led to some landlords not allowing solar panels to be installed on their roofs.

In this article, we will cover the potential hazards that can cause fire outbreaks on solar installations, traced to solar panels, inverters, batteries or from the installation of the solar system itself, as well as what can be done to prevent such solar disaster from happening.

We have also made a detailed solar safety video illustration on this topic. You can watch it below:

1. Hazards That Can Lead To A Fire Outbreak From Solar Panels

These are fire outbreaks from solar installations that can be traced primarily to the solar panels itself. Factors that can can cause or contribute to it are:

• Broken panels: Solar panels whose glass is broken, cracked or shattered panels can create what is called hot spots, which are basically heat concentration on some areas of the solar panel. These hot spots which also follow lines of weakness on the solar panels called snail trails, are a sign of electrical current not flowing properly through the solar panel. The hot spots on the solar panels can get so hot and start burning from underneath.
• Faulty Diode: The diode which is located inside the junction box underneath the solar panels control the flow of electrical current. If the diode goes bad, it will be unable to direct the flow of current around shorted cells/shaded areas of the solar panels. This creates the dreaded hotspots that can result to a fire.
• Manufacturing Defects: This is rarely a case. An extremely rare number of panels, with exceptional low quality, can come with some manufacturing defects.
• Buying Used (Tokunbo) Solar Panels – Many used solar panels exported to mostly third world countries like Nigeria are approaching their end of product life cycle use, where they become very costly and difficult to discard and recycle. Some of these solar panels are outrightly bad. Snail trails and minature cracks can also appear on aged panels during over its many years of use. These lines of weakness are signs of poor flow of electrical currents which creates hotspots that can potentially lead to a fire outbreak.
• Undersized Cables: Using a lower size of solar cable can led to a fire outbreak because the wire cannot handle the amount of current flowing through it. It gets hot, melts the insulators, bridge and can burn.
• Poor Installation – Doing a wrong connection, improper use of electrical tapes to mask wire connections which can fall out with cycles of rainfall and dryouts, solar wire pressed tightly on sharp edges like roof and window frames, etc.
  
  Prevention:

• Do not use broken solar panels. If any is found to be broken during the course of installation, it is best to get a new one.
• Use the right size of solar wire for installations. Also confirm originality from seller.
• Buy quality brands of solar panels.
• Scheduled maintenance to clean and remove large debris from solar panels.
• If you must buy imported or locally used solar panels, have an experienced professional check it first.
• Have only experienced solar techicians install your solar. Ensure all safety guards including solar panel mounting racks and holders, etc are used.

Hazards That Can Lead To Inverter Fire

Here are potential causes of fire outbreaks on solar power installations whose root cause can be traced to the inverter itself. They include:

• Overvoltage: Especially on high frequency/high voltage solar hybrid inverters. When the voltage from the solar panel connection exceeds the maximum allowable by the inverter, the inverter can overheat and burn.
• Undersized Wires: If the wire feeding in and out the input and output of the inverter is undersized or of poor quality, the wires can burn out and start a fire.
• Inverter ver Heating: An inverter can overheat and potentially cause a fire if its safeguards fail. This can happen due to a component failure like the fans or an internal short circuit inside it.
• Poor Installation: A poorly installed inverter creates a big fire hazard. Inverters should have a minimum amount of spacing between its blow out fan and the wall or barrier, to ensure free expulsion of heat. Inverters should also not be installed in direct sunlight but in well ventilated areas away from water intrusion. When these are not adhered to, it can heat up, short circuit and pose a fire threat.
  
  Prevention:
• Proper inverter voltage sizing: In stringing up your high frequency or high voltage solar hybrid inverters, do not max out the inverters maximum open voltage capacity, but make adequate room for voltage spikes during cold weathers.
• Aim for higher quality inverters that have a degree of inbuilt fail-safe protections like overvoltage and over temperature protection.
• Get a professional to install your solar inverter systems and ensure only recommended components are used.
• Maintenance & Monitoring – Repair faults as soon as they occur and watch out for irregularities such as unusual noise, heat, etc.

Hazards That Can Lead To Inverter Batteries Exploding & Burning

Inverter batteries, especially lithium batteries are a leading cause of fire in solar power installations. Lithium batteries offer a much higher energy density but it must be installed following the manufacturer’s instruction.

The following are potential hazards that can result to fire outbreaks from the battery component of a solar installation:

• Overcharging: A dead or highly suplarated batteries with faulty or shorted cells might keep up absorbing current & heating up and can swell and explode. Solar inverter batteries can also be overcharged by faulty inverters or solar charge controller. However, this should not be confused with battery equalization which is a controlled overcharge for maintenance and longevity.
• No Battery Management System (BMS): This is compulsory for lithium batteries to effectively communicate with the inverter.
• Battery mismatch: Mixing old and new batteries or batteries of different sizes can lead to the batteries overcharging and overheating.
• Physical damage: This can happen from falls, bent terminals, etc. In lithium batteries, this can also lead to thermal runways which can result to fire breakouts.
• Poor battery maintenance – When the distilled water in tubular batteries dry out, they overheat and dangerous levels of hydrogen gets released and a shorted cell can led to fire.
• Battery’s inherent fault – This majorly comes from internal short circuited cells from age or manufacturing defect.

Prevention

• Use only quality chargers (inverter, battery charger, solar charge controller), and only charge at the recommended charging currents.
• When installing lithium batteries, ensure that the inverter has a battery management system (BMS) and is compatible with the lithium battery itself.
• Discard faulty batteries, don’t attempt to improve capacity by mixing old and new batteries.
• Watchout for physical damages on new batteries.
• Proper maintenance and monitoring – Ensure distilled water for tubular batteries don’t go below the minimum level. Watchout for signs of issues like excess bubbling, heat, swelling, smell, etc.
• Buy good quality battery brands.

Causes Of Fire On Solar Energy Systems Due To Poor Installation

These are faults from the installers and installation process itself that can result to fire. Many of the potential hazards listed above also cuts across the installation and can be avoided if an experienced technician does the solar installation. Most of the risks from the installation itself arises when one buys solar components themselves and looks for nearby electricians, who might not be qualified or experienced for the job.

An experienced solar engineer will know how to properly mount solar panels and insulate them properly, the necessary protections to install for any solar setup, how not to surpass an inverters recommended voltage, detect wire mismatch, understand proper setups, etc.

Natural Acts

While not explicitly categorized, fire in solar installations can be attributed by uncontrollable acts of nature like flooding, strong winds, rodents chewing away wiring insulators, etc. These can topple solar setups, rip wires, bridge wires and cause short circuits that can potentially start a fire.