Batteries for Solar
The introduction of Solar Panels was a godsend for homeowners who lived “off-grid”. Large banks of lead acid batteries were necessary to run just a few lights and a fridge or two. Simply because the electricity grid was too far away. Solar panels became the best solution to keep your Batteries charged. Costs very little to run, much cheaper than that thirsty old generator. Now it's the old lead-acid batteries turn to be updated. Lead acid batteries have a number of shortcomings.
Enter the Lithium-Ion battery.
Although Lithium-Ion batteries have been around for a while now (invented in 1980), the latest ones have now developed into a very compact yet powerful energy storage unit. From mobile phones and laptops to power tools and electric cars, they have become a part of our lives. They hold many advantages over traditional batteries. They are lighter with a much higher energy density. Low maintenance with no “memory effect” they don’t require ventilation or to be kept upright, they can be run completely flat, with a superior life cycle as well.
How do Home Energy Storage Systems work?
Although it requires some pretty Hi-Tech equipment, the concept is fairly simple.
There are 4 basic components.
1. A Power Source. Some systems can charge from the Grid but Solar Panels provide your power for free.
2. A Battery Controller. To direct the power where we want it to go.
3. An Inverter. To covert the DC Solar electricity into 240 Volts AC, which powers your home.
4. A Battery. To store your power to use later when the sun goes down.
Storage Systems can be programmed to run in a number of different ways. For a home that is Grid Connected with a Smart Meter, the best use of your battery is to save your excess free solar generation for night time use, when electricity prices are much more expensive. During the day your home will use your own Solar power first and the excess generation will feed into your battery. Once the battery is fully charged the excess electricity will be sent back to the Grid. Your meter will count it and you will receive a credit for that electricity on your next power bill.
AC CONNECT or DC CONNECT ?
Now it gets a bit more interesting. There are two very different methods of connecting a battery to an Energy Storage System. The traditional method is DC Connect and the other is AC Connect. An Inverters job is to convert the DC Solar Power to AC power to use in your home. There are two distinct sides on every Inverter, DC and AC. All batteries store DC power. When we connect the battery on the DC side of the Inverter, power can be sent directly to the battery without any conversion. This is known as DC Connect. AC connect is when the battery is connected after the power has been converted to AC. Each method has advantages over the other.
DC coupled advantages.
* The traditional, simple and trusted method.
* More efficient as there are always some losses when power is converted. Typically running at 48V DC.
* The new Hybrid Inverters have the Battery Controller built-in to the DC side of the inverter. This makes it an all in one solution. A consumption meter is also required so the inverter knows what your current usage is.
AC connect is a newer approach to Energy Storage Systems. A standard grid-tie inverter converts the DC solar power to AC power, and then connects to an AC battery. An AC battery is basically a DC battery with an inverter built-in. The battery controller can also be in there as well or in a separate box or location.
AC coupled advantages.
* Will connect to your existing solar systems inverter.
* More efficient when running AC loads during the day.
* More options to expand in size.
So which connection method is right for you?
The answer is... it depends on your situation and what you wish to achieve. Both methods can be grid connected or completely off grid. Different manufacturers tend to support one or the other. LG Chem is the exception. They have a 48V DC and have just released a 400V AC ready battery. You need to understand your homes loads and how you use your power before deciding which way to proceed. This is the time to call in the experts. As there are new products being released all the time, we need to keep up to date with all the latest tech to make sure our customers receive the very best solution available.
What size Battery should I invest in?
High quality Lithium-ion based energy storage systems have finally reduced in cost enough for them to actually pay for themselves before their warranty expires. But not all of them, and it depends on your power usage habits and bills as well. We stock a variety of quality brands and sizes to cover most situations.
These are the brands we use and recommend:
DC Connect Batteries
In 2016 LG Chem launched it's new range of battery products to the solar market: The LG RESU High Voltage (400V) now compliments the original low voltage (48V) lithium battery.
The RESU battery is an Optimized Solution for Energy Saving and High-quality Power Energy Storage System(ESS). It stores electric energy for later consumption. It is designed to improve energy efficiency, by enhancing the quality of renewable energy that results in the stabilization of power supply system. LG Chem provides an optimal energy solution for users via our state-of-the-art energy storage system with a long lifespan and a top-notch quality.
Innovative and Reliable
High reliability and safety with prismatic cells from Samsung
Robust BMS provides multi-protection at both cell level and system level
Over 95% depth of discharge to maximise the usable capacity
Suitable for both free-standing and wall-mountable installation
One-click online firmware update
Remote monitoring of battery status with App and web portal
Smart hibernation technology to maintain battery state of health
AC Connect Batteries
The Enphase AC Battery is an integrated energy storage system that combines a 1.2kW Lithium Battery with a 270W inverter to create a very modular solution for any solar enabled home. Once an Envoy has been installed, AC Batteries can be added one at a time. This system brings you more intelligence and the industry’s lowest cost of entry. It pairs seamlessly with all Enphase microinverters and any other solar inverter to help you make the most of your solar energy.
The AC Battery’s modular architecture means you’ll get a storage solution that’s exactly what you need: no more, no less, no wasted costs. The system is easy to expand on as your needs change, as your family grows or you add an electric vehicle. Plus, flexible configurations work for any garage.
Electric Vehicle manufacturer TESLA has just released it new Powerwall 2. The new Powerwall 2 as a usable capacity of 13.5 kWh and Power throughput is 7kW peak and 5kW continuous.
With its 10 year Warranty it will maximise Solar self-consumption and assist time of use load shifting. It can also provide backup power during utility outages. Compact, stackable and with a built-in inverter, Powerwall also comes ready to integrate seamlessly with solar, enabling you to self-power your home and even go off-grid, if you like.