‘Do we have any candles? Quick – check outside to see if it’s just us!’ – ancient Aussie proverb.
Australians are no strangers to blackouts. Our grid is overloaded at the best of times and it doesn’t take much to tip it over the edge. So, how can solar batteries help to keep the lights on? The answer is called ‘blackout protection’.
There’s a big misconception that if you have a solar and battery system you’re automatically covered in the case of a blackout. Unfortunately, that’s not true. Your solar system is connected to the grid, so running your system like normal during a blackout could result in your solar power going back onto the grid, zapping an electrical worker as they work to fix the line.
As a result, all solar or battery inverters automatically disconnect from the grid when there is a blackout for safety reasons. Opting in to ‘blackout protection’ is the only way to keep your lights on during a blackout.
What is blackout protection?
Battery systems that have a blackout protection feature still disconnect from the grid during a blackout, but they have a secondary circuit connected to one fuse in the meterboard so your battery can still provide power to that particular circuit during the blackout.
Which appliances can you use while in ‘blackout mode’?
People often think that blackout mode will enable them to use all their appliances normally. This is not the case. Blackout mode will only cover your essentials – and rightly so. Most batteries are designed to cover your night time energy needs in normal operation which wouldn’t be helpful during a blackout when you may need power for longer than that.
While a bit different in practice, the concept is similar to the ‘flow rate’ of your battery, which you can read more abouthere. The idea is that you can’t overload the battery during blackout mode, otherwise it will shut off. For that reason, appliances that have a high start-up energy draw will trip the battery even if their normal operating needs are pretty low. You can see a video of a battery tripping during blackout mode on Youtube here and here.
What appliances can I run during a blackout?
A typical home setup for blackout protection includes the fridge, some lights, a few power points to charge phones, computers and keep the Wifi running.
What it doesn’t include are running energy intensive appliances such as an air-con, pool heater, space heaters, washers, dryers and the like.
We put together a comparison of the most popular batteries in Australia today so that you can see what’s out there.
|Battery Model||Battery Capacity||Max Inverter AC Power Output – Blackout Mode||Max Inverter AC Power Output – Normal Operation||Battery DC Charge/Discharge current|
|ALPHA ESS 5.7kWh||5.7 kWh||4600 W/20A||5000W/21A||100A|
|ALPHA ESS 10.1/10.3 kWh||10.1/10.3 kWh||4600 W/20A||5000W/21A||100A|
|ALPHA ESS 10.1/10.3 kWh||10.1/10.3 kWh||5000 W/22.8A||5000W/22.8A||100A|
|LG Chem RESU10H||9.8 kWh||5000 W/22.8A (3300W recommended)||5000W||11.9A to 14.3A|
|LG Chem RESU13 LV||13 kWh||5000W/22.8A (3300W recommended)||5000W||65A/50A|
|Telsa Powerwall 2||14 kWh||5000W/21A per Powerwall||5000W/21A||100A|
*Please note that this data is sourced from publicly available datasheets as of 11 August 2020 and is subject to change.
One last thing to remember – when it comes to blackouts, inverters matter!
If being protected during a long blackout is important to you, make sure your solar system has a hybrid inverter. Many battery retrofit systems that connect onto existing solar panel systems don’t allow you to charge your battery during the blackout period. In that case, once you drain your battery, you will be left without power until the grid comes back. A hybrid inverter controls both your panels and your battery. This means you can recharge your battery from your panels even in blackout mode. A good example of this is the Alpha ESS Hybrid inverter
Want more info? Check our Frequently Asked Questions below
What is a brownout and blackout?
A brownout happens when local electricity demand is near or above the local grid capacity and the utility will intentionally tap down the grid voltage to prevent blackout. Electricity will still be available but may cause appliances such as lights to dim.
A blackout is caused by a complete loss of electricity connection due to various factors such as extreme weather and local grid being over capacity.
What happens with blackout protection and how it is wired?
A separate output cable from the battery system’s UPS/EPS/Backup port will be wired directly to a selected number of circuits in the switchboard, protected by a main battery circuit breaker and a changeover switch.
Can I have blackout protection installed with my battery system?
In most cases the answer is yes but it depends on the product you select, the condition of the switchboard and where the battery is to be installed.
How many circuits can I have on backup and what is the maximum output?
Output of the blackout protection is limited by the battery and/or inverters maximum output capacity. So, if a battery system is connected via a 5kW inverter, then the backup power is limited to 5kW or 20A. Recommendations are 1-3 essential light & power circuits less than 20A at max demand (ALPHA ESS battery for reference).
Can the entire house power during blackout mode?
Generally you cannot power your whole home during a blackout due to things like the battery output limit, high usage surge and high max demand (from air conditioner units for example) can easily overload and shutdown a battery system in blackout mode. Houses are typically rated with a max demand of 60-80A which is 3-4 times higher than most battery models.
What are some accepted and unaccepted appliances to be put under blackout protection?
Most inverter manufacturers would have documents stating what is allowed in the blackout protection.
We generally see that lights, fridge, TV/computers, internet router, ovens and cookers are acceptable. The key is the power rating of the appliance must be below the battery’s maximum output.
Unaccepted appliances are typically any types of pumps, air conditioners, heaters, vacuum cleaners, and any high-powered appliances with high start-up current.
Is the battery backup automatic when there is a blackout?
In most cases, yes. You need to confirm your battery inverter has that functionality, but most do.
Can my battery still charge from my solar panels during a blackout?
It depends on the make and model of the battery inverter. If it is connected directly to a hybrid inverter with panels (like the ALPHA ESS SMILE5 or SolarEdge SE5000 for example), then yes. If it is AC-Coupled to an existing grid-connected only inverter, then most likely it cannot charge from your solar panels during a blackout.
Can I have blackout protection on all three phases?
As the blackout protection is connected to a single circuit, you would need to choose one circuit on one phase for the blackout protection to use when activated. You cannot have power doing to all three phases when you are in blackout mode.