Batteries We Recommend
The Powerwall is the new ‘superstar’ of the solar energy world! It is a wall mounted, liquid thermal controlled unit weighing around 100kg – which is pretty impressive when compared to much heavier traditional deep cycle batteries. This unit is single and three-phase compatible, has a 7kWh capacity (6.4kWh usable) and a 3.3kW continuous/peak output capacity.
With this unit, multiple batteries may be installed together – up to 9 units for the 6.4kWh battery which would provide the average Australian household with more than two days power supply from battery storage alone.
Another benefit of the Tesla Powerwall is that it is ‘outdoor rated’ as its lithium-ion chemistry does not (unlike many on the market) deteriorate while operating at above 25°C or below 5°C.
While the Powerwall looks great and has a small footprint, it doesn’t include a solar inverter or an energy management system, so it needs to be paired with compatible technology if it’s being used to store and manage rooftop solar generation.
Enphase has a ‘plug and play’ modular lithium-ion phosphate 1.2kW battery which is more affordable than and arguably as effective as the Powerwall. Coupled with the cloud-based Enphase Energy Management System, the system is designed to help households to store and manage their rooftop solar energy supply and control their overall household energy use on a single platform.
It pairs seamlessly with Enphase micro inverters so it’s a far simpler installation process than a Powerwall and is also modular so it can be easily scaled if required. It runs two cycles per day for twice the value and faster payback and is extremely reliable utilising state of the art highly stable, lithium iron phosphate chemistry from Eliiy Power. There is no high-voltage DC in system and Enphase batteries have a minimum 10-year expected life.
LG Chem Residential Energy Storage Unit ( RESU) systems have a proven track record in Australia. LG Chem use Lithium-ion battery cells which are very thin and are manufactured in long ribbons. They employ a manufacturing method called lamination and stacking, where they cut the rolls of cells into sheets and stack them flat on top of each other. This eliminates dead space and minimizes distortion which increases efficiency and battery life.
There are now five LG Chem RESU systems to choose from with nominal capacities ranging from 3.3 to 9.8 kilowatt-hours. The three smaller RESU systems use 48 volt DC power and the bigger two use around 400 volts – similar to the Tesla Powerwall.
The two different voltages allows for a wide range of installation options including DC and AC coupling. The 48 volt RESUs have higher power than most comparable battery systems. They are warrantied to retain at least 60% of their nominal capacity for 10 years or until they have stored around 2,500 kilowatt-hours for each kilowatt-hour of nominal capacity (approximately 3,200 cycles).
These batteries compare extremely well against any other similarly rated storage solution in the market.
- Lighter and significantly more compact than any comparable battery.
- Can be used in an indoor or outdoor environment.
- Are maintenance free
- Suitable for on-grid or off-grid use.
- Extremely quiet – no cooling fan (rely on natural convection)
- Great Fire Safety Rating – LG claim theirs is the safest lithium-ion battery available.
- Extremely efficient – they have a high Nominal Battery Capacity (total amount of energy the battery can hold) – approximately 90% for the 48 volt RESU units and 95% for the two higher voltage units
- Plenty of Installation Options – All of the inverters Solar Mad recommends can be used with the 48 volt units. The smaller units can be installed without a compatible inverter by using a DC converter. This means they are suitable for almost any new or existing solar panel set up.