New battery installation rules

If you’re planning a battery or you already have one, the new rules on where batteries can be located and who can work on them may affect you. Renew’s Andrew Reddaway explains what’s changed.

Many Renew members already have solar batteries helping to power their home, often installed many years ago as part of an off-grid solar system at a remote property. Many more are watching the battery market, waiting for economics to improve before adding a battery to their grid-connected solar system in the suburbs. Some have installed small DIY solar and battery systems in sheds. All these people are affected by a new Australian Standard published on 11 October 2019 that significantly tightens the rules on where, how and by whom batteries can be installed and maintained.

Renew has published a new discussion paper to inform intending battery purchasers about the new standard, so that they can discuss the requirements with their installer, and plan for them, and to help existing battery owners understand how the rules affect them. The paper and this article discuss the contents of standards documents, but these are only brief descriptions and are no substitute for reading the actual standards.

Overview of the new standard

The new standard AS 5139 applies to batteries installed in a fixed location whose voltage is at least 12 volts and whose energy storage capacity is at least 1 kilowatt-hour (kWh). The standard applies to homes, garages, sheds and commercial properties but not to caravans, tiny homes with wheels, electric vehicles, uninterruptible power supplies or telecommunications applications.

The standard groups batteries into three categories. Categories 1 and 2 cover lithium batteries that appear on the Clean Energy Council (CEC) list of ‘approved’ batteries and which have been tested to comply with electrical safety requirements in the Best Practice Guide. Lead-acid batteries are all in category 3, along with some lithium batteries. Below is a bit more about which batteries are included in each category and the way they are addressed in the standard.

In category 1, you’ll find a battery such as the Tesla Powerwall 2, which is a self-contained appliance. It includes internal safety switches as well as an inverter so it can deliver standard 230V AC power to a house switchboard via standard 230V household wiring. This is called a ‘pre-assembled integrated battery energy storage system’. This category has the fewest installation requirements. It’s covered by 10 pages of the standard which mostly relate to restricted locations, testing, commissioning and documentation and frequently defer to the manufacturer’s manual.

In category 2, you’ll find a battery such as the LG Chem RESU 10, which includes internal safety switches but no inverter since it’s designed to be connected to an inverter via a power cable. It’s called a ‘pre-assembled battery system’. The standard devotes 26 pages to installation requirements for this category. In addition to the items noted for category 1, it includes detailed requirements for wiring, fusing, earthing etc.

Category 3 covers batteries that are not on the CEC’s approved list. This includes all non-lithium batteries (including lead-acid), pre-assembled lithium batteries not listed by the CEC and lithium batteries that are not pre-assembled. The standard dedicates 44 pages to installation requirements for category 3 including items such as battery enclosure design, ventilation, voltage drop and arc flash.

Batteries fall into three categories in the new standard: All-in-one lithium systems, like the Tesla Powerwall are in category 1, while enclosed lithium systems with charge control, but no internal inverter are in category 2. Batteries not on the CEC approved list are in category 3; this includes bespoke assembled battery banks.

Installing a new battery

When installing a new battery, the new standard is more restrictive on location than previous rules and guidelines, making it harder to find a suitable location for a home battery. The most likely battery locations are on an external house wall or in a garage.

Batteries aren’t allowed:

  • in habitable rooms (bathrooms, laundries, pantries, hallways are not habitable rooms)
  • in ceiling spaces or wall cavities
  • under stairways or access walkways
  • in an evacuation route or escape route
  • near combustible materials.

The standard requires clear space between the battery and any windows, doors and appliances such as hot water units and air conditioners. This clear space must extend at least 600mm to either side and 900mm above the battery.

If the battery is wall-mounted with a habitable room on the other side, the wall must have a non-combustible barrier extending the same dimensions as the clear space noted in the previous paragraph. Most likely the installer will add a thick cement sheet unless the wall is already made of cement sheet, brick or concrete.

A battery in a garage may need a bollard to protect it from cars.

In addition, a battery in category 3 isn’t allowed under the floor of a habitable room. It is also restricted to a structure detached from the house such as a shed if either of two conditions apply: its chemistry is lithium or it’s a powerful battery that can create a dangerous arc (arc flash) in the event of a short circuit.

There are additional requirements in the standard, but these relate to wiring and other areas that should be addressed by your installer.

A battery system mechanically protected by a bollard in a garage.

Maintaining an older off-grid battery

Many existing off-grid households use lead-acid batteries and are experienced in performing regular maintenance on them such as topping up water levels, cleaning and tightening battery terminal bolts and checking cell voltages. Such maintenance is recommended by the Australian Standard for off-grid power systems, AS 5409.

The main safety risk mentioned in the previous battery standard AS 4086.2 was spillage of acid from the batteries. That document states that someone doing routine inspection and maintenance should wear goggles or a face shield plus overalls or a dust coat, and tools used during maintenance should be insulated to help prevent an accidental short-circuit.

Under the new battery standard, protective clothing requirements have in many cases escalated dramatically. AS 5139 requires that anyone working on a battery calculates the ‘AFIE’ value—a value indicating the battery’s risk in the event of a short-circuit—and then looks up a table listing the protective clothing necessary for that value.

Unfortunately, this leaves many off-grid households in a difficult position because they probably don’t have a copy of the standard. Even if they purchase the document, they may lack the technical skills to understand the complicated AFIE formula or to select appropriate input values for it. Their battery is an expensive investment and must be maintained to conserve its lifespan and fulfil warranty requirements. Many people will be unaware of the new standard’s existence and may be inadvertently violating state regulations by not following it.

To comply with the new battery standard, one option for off-grid householders is to calculate what protective clothing is required, and obtain and wear it when maintaining the lead-acid battery.

Another option is to engage a solar-qualified electrican or solar installer to upgrade the battery system, aiming to reduce its potential risk in the event of a short circuit. A simple solution mentioned in the standard is to install a fuse between two of the battery cells that were originally connected by a simple cable. This dramatically reduces the battery’s potential risks because in the event of a short-circuit the fuse will disconnect quickly (for example in 0.1 seconds) so the electrical arc doesn’t have time to fully develop. For the hypothetical battery noted above, installing such a fuse reduces the AFIE to 0.21 and it appears that the standard doesn’t require special clothing to protect against arc flash.

A third option is to have a professional perform maintenance on their battery. This might be expensive and inconvenient, especially for flooded batteries that require regular topping up with water. For such batteries it’s possible to install an automatic watering system which should remove the need to regularly work close to the battery cells.

Many batteries will require fireproof barriers extending considerably past the bounds of the battery itself.

DIY off-grid systems

Many solar enthusiasts and handypeople have installed small off-grid solar systems in sheds on a DIY basis. For example, the battery in such a system might be connected via direct current to a light globe, a water pump for gardening and a small removable inverter for charging power tools. In the past it was possible for such systems to comply with standards if the installer was a ‘competent person’ and the solar and battery voltages stayed below 120 volts which was the limit for extra low voltage (ELV).

The new battery standard abolishes ELV, instead defining three ranges of decisive voltage classification (DVC). These are categories used in some overseas standards. Non-electricians are now restricted to DVC-A, which includes DC voltages up to 60 volts and AC voltages up to 35 volts.

At first glance this limit wouldn’t affect a 12, 24, or 48-volt battery. However, small solar systems often include a solar array with a higher voltage, connected to the battery via a charge controller using maximum power point tracking (MPPT) technology.

For example, two solar panels might be connected on the roof in series so the cable leading to the charge controller carries a voltage up to 90 volts. Since this  voltage exceeds DVC-A, under the new standard this is no longer allowed for non-electricians. Even working on the connected 48-volt battery may not be allowed since the charge controller might use a type of ‘non-isolated’ electronics to convert the voltage, which can’t be sufficiently trusted to isolate the battery from the higher voltage, according to AS 5139.

Apart from the voltage level, AS 5139 includes many other requirements for battery installation—refer to the standard for details.

To comply with the new standard, a shed-mounted existing solar system with voltages above 60 volts shouldn’t be worked on by a non-electrician. If work must be done, options include:

  • Contract an electrician whenever work is required.
  • Reduce solar voltages to below 60 volts. This probably entails using a different charge controller.
  • Reduce the battery size to below 1 kilowatt-hour of energy storage so the new standard doesn’t apply.
  • Make the installation portable so the new standard doesn’t apply.

Are changes required to existing systems?

Many batteries were installed before publication of AS 5139 in locations that don’t comply with the new standard, such as within 600mm of a window.

As with most safety standards, this one is not immediately retrospective and thus won’t necessarily require existing systems to be brought up to current standards. However, if an existing system is expanded (by adding or replacing batteries) then it would likely trigger the requirement for the whole system to be brought up to current standards.

Some batteries have been marketed as ‘expandable’, but achieving this could be difficult if the battery must be moved or the wall it’s mounted on must be made fire-proof.

Is the new standard too onerous?

The new battery standard aims to improve public safety by minimising the risks posed by batteries. These risks are real, as proven by several incidents involving hoverboards, electric bicycles and mobility scooters, and even home energy storage batteries.

On the other hand, some countries even allow batteries in habitable areas. Sonnen says that tens of thousands of its batteries are installed this way in Germany.

Long life spans must be considered, as it’s possible that an Aussie home battery may sit with minimal attention for two or three decades spanning multiple home occupants. Electronic and chemical components degrade over time, reducing confidence in the battery’s safety. Perhaps German regulations ensure inspection and maintenance to a higher standard than in Australia.

One problem with the new standard is that it doesn’t differentiate between different lithium chemistries. For example, lithium iron phosphate (LiFePO4) and lithium titanate (LTO) batteries are generally regarded as safer than those using lithium nickel manganese cobalt (NMC) as it’s quite hard to make them burn. It also doesn’t differentiate between the quality of manufacture of different products on the Clean Energy Council list. In the absence of guidance by the standard, these factors are the responsibility of consumers to consider.

In Renew’s view, clearances required from windows etc are insufficiently flexible, as they don’t consider that risks vary according to a battery’s energy storage capacity, its chemistry and the fire resistance of its cabinet. For some batteries smaller clearances should be allowed.

The new restrictions on DIY solar systems in sheds are quite harsh. In comparison, New Zealand has some lenient rules, even allowing some DIY wiring for grid-voltage appliances in houses.

Summing up, in Renew’s view some of the new standard’s provisions are too onerous. However, it’s better to have an imperfect standard than no standard at all, which was the case up until October 2019. Hopefully future editions of the standard will strike a better balance.

Protective gear for maintaining batteries under the new standard can include fire rated clothing, face shield and goggles and even a fire-rated balaclava. The level of protection required depends on the arc energy level, which must be calculated from information in the standard. However, adding a simple fuse between two battery cells in a battery bank could obviate the need for most of this protective equipment as it reduces the arc energy potential below the required threshold. For more information, see the discussion paper at Image:

Thanks to Glen Morris from SolarQuip for his assistance with the discussion paper this article is based on.

Andrew Reddaway
Andrew is an energy analyst at Renew.

More info:

The full paper includes more details on the new standard and how to address its requirements, and is fully referenced. Find it at

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