Batteries are often in the news these days, and more and more we get asked “I want a system that doesn’t have a battery now, but one I can add to later”. This article will discuss the pros and cons of buying a “battery ready” system.
Should I get a battery now?
Probably not. Batteries are expensive. Under recent rebate schemes, batteries were much more affordable. We should know – we were the among the top installers under the 2019 Queensland battery scheme, installing over 400 systems. However, at their current price point, we recommend most people do not buy them – the payback period can be many years.
That said, if you get regular power cuts/blackouts, or have peak demand charges, batteries may still make sense. In the case of a black out, they can keep you running until the power returns. If you have high peak demand changes, you can have the battery discharge only when consumption is above a certain threshold, to keep the amount of energy imported from the grid low.
In addition, there are other circumstances where a battery purchase might make sense right now. For example, if you have just moved into a home that you intend on spending 10-years + in, and you are not worried about a very quick return on investment, then a battery system may be for you right now.
Or, you may be focused on your carbon footprint in addition to your costs. In which case the calculation for whether a battery is worthwhile is very different to one that is coming purely from a financial standpoint.
Lastly, we have found that lot of our battery customers are tech enthusiasts and keen to adopt cutting edge technology early, even if they pay a premium for the privilege. A solar and battery system for your home provides a really clever way of monitoring, adjusting and regulating your energy consumption to create a smart-home environment. This is a movement that is just beginning with intelligent automation and computerisation, meaning you can turn you home into a tech show case for energy efficiency.
What does a ‘battery ready’ system include?
There are two ways of having a “battery ready” system without a battery.
The first is to realise that any solar energy system is battery ready. Often “battery ready” is used as a marketing term, so beware companies using it as a key selling point. By using an “AC coupled” system, you simply add a battery charger to your current inverter and hook a battery up to it. Too easy! The main downside of this is that with current regulations you can only have 10kW of inverter capacity per phase without special permission, and a battery charger counts as an inverter. Most residential properties are single phase, meaning if you have a 5kW inverter, you can have a maximum 5kW battery charger. The maximum power your solar system will output is 5kW, and that first takes care of your usage before the remainder is used to charge your battery – so if you have high usage, the battery won’t charge.
The second method is to get a hybrid inverter. This is an inverter you can attach a battery to out of the box. The advantage of this is that a 10kW hybrid inverter can (potentially) provide 10kW of power for your house, or 10kW of power to charge your battery. However, hybrid inverters can be more expensive, and if you don’t have a battery it’s simply added cost. It’s also worth considering the timeframe in which you intend to add a battery, as regulations and technologies change, and it may not be possible to add a battery to your 10-year-old hybrid inverter.
What should I do instead?
Our advice for most people is to forget about batteries or hybrid inverters and spend the money on a bigger, better quality system from the get-go. Compared to a 6.6kW Trina/Solax hybrid “battery ready” system, a 10kW Q-CELLS/Fronius configuration will generate more power (so save you more now) and has a better warranty (so save you more for longer). Don’t forget, you still get paid for exported electricity – it’s never wasted.
However, if you are keen on a battery, it’s best to get one at the same time as – or very soon after – getting a system. If this is your plan, buy a hybrid inverter, as it works out cheaper than buying an inverter and separate battery charger – and takes up less space on your wall. The only time we’d suggest an AC-coupled solution is when you have a battery with a built-in battery charger, such as Sonnen.
Another alternative is to consider using power diverters, such as the Powerdiverter. This makes your excess solar energy – that which would otherwise be exported – heat your hot water or turn on your AC. This is a bit like a battery in that it “stores” the energy, but instead of storing it as electricity, it stores it as hot water or a cool house.