Updated: Aug 7, 2020
Many people getting into solar or any form of electrical battery backup for their house or work, often have some questions... What components do I need? Where do I buy it? Who installs and sets it up? How much will it cost? What size must it be?
I often get the question: Can we buy your batteries and then we run our house on that? Unfortunately, you need a bit more than just batteries! Essentially, for a full solar system you need energy production (solar panels), energy storage (batteries), energy conversion (inverter) and energy distribution (wiring and switches to connect the components and to your house electrical circuits).
In this short post, I will try to summarise the absolute basics that you need. I will later do a follow-up post to show the components in action, and perhaps post some videos showing what a typical install looks like. Below, I also show the typical costs (as of August 2020) of what each of these components should cost , assuming a typical small residential install. (I will go into sizing in a separate post.... that is a whole topic on its own!) Costs are influenced by the type of components you buy and their features and capabilities, but in this example I go mid-range.
There are two main types of electric backup systems:
Backup power only: I want power for a while when the mains go out. (I.e. during load shedding.)
Solar: I want to generate and use my own power (party or in full), to have backup power but also to save on my monthly electric bill.
Option 1 is the simplest. As a minimum you will need:
An inverter to convert your battery power into usable higher voltage power that your household 230 volt appliances can run on. (R15,000)
A mains charger to charge your batteries when you have mains power. (Almost always also built into the inverter, but add R5,000 if not included)
Batteries (Cheaper batteries such as lead-acids: R30,000 and will last about 4 years. Higher grade batteries such as lithium ion phosphate: R60,000 and should last 10 years+.) I will go into the benefits of lithium ion phosphate (LifePo4) in a separate post; there are many!
Option 2 requires two additional components added to the above:
Solar panels (12 will be enough for a small to medium install) = R25,000
A solar charge controller that converts the power from your panels into the right voltage to charge your batteries. (Sometimes also included as part of the inverter. Add R5,000 if not included)
Then additionally, for any of these options you often also need:
A solar installer that sets up inverter, connects your batteries and (most importantly) installs solar panels on your roof. The installer also wires all of these components together. If you have enough knowledge and are qualified to do so, you can often do most of this yourself. (R7,000)
An electrician, to wire your inverter into your house main electric distribution board, add a sub-DB for your solar system, add some manual cut-over switches, and make sure the whole system is electrically compliant. This is needed if you want to seamlessly switch to backup power, without you even knowing it. (R7,000)
Battery cables, fittings, solar panel DC wire, etc. (R5,000)
Then, there are some "nice to have" extras to consider, such as:
A battery monitor. It measures electricity flow precisely and greatly improves your ability to measure how much power you are using and what you have left in your batteries. R3,000
Remote monitoring devices that store and/or publishes data to some form of web portal. Allows you to view all your data and statuses, but also sometimes to configure your equipment remotely. (R3,000)
In essence, that is it! So, it is more than just batteries. The above components function as an integrated system to produce, store, convert, manage and distribute power into your household.
Organising an installer is sometimes a bit complex. There are "all in one" companies that do everything, and you buy everything from them also. This is more expensive (they add higher markup) and often they sell very specific brands, but has the benefit of you working with a single service provider. Alternatively, you could buy your components from different providers if you want, separately have a solar panel installer to hook up your system, and separately an electrician to do the distribution board wiring and any mains switches etc. Some people prefer to go that route, and it gives you more flexibility.
I will go into more practical detail, features of components and also show examples of installs and how to plan precisely what you need for your home in a separate post.
Happy to get your comments and feedback on these components, and if there are any other key minimum factors you believe one should consider. Cheers!