How solar batteries can help you wave goodbye to your electricity bill

Are you South African? Then I bet I can spoil your mood with one song lyric. No? Check this out:

“Hello darkness my old friend…”

When it comes to power outages and sitting around in the dark, we are so over it. Let’s take a look at solar batteries and how they fit into the big picture of keeping your lights on, and your blood pressure normal .

If solar panels work with the sun, why do they need batteries?

They don’t. The name is slightly deceiving, but solar batteries are simply batteries that are charged with energy from solar panels. The panels, of course, convert the sun’s rays into energy.

The batteries then store this energy for later use, allowing you to make use of solar power even when the sun isn’t shining. This way you get more out of your solar system and need to rely less on the grid.

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Which kind of solar battery do I need?

There are various types of solar batteries on the market, and your decision will be based on your needs and budget. Consider the following:

  • Lead acid batteries. These have been around for a long time, and are the most common option. They are reliable, easiest on the pocket, and easily disposed of and recycled.
    We can distinguish between flooded and sealed lead acid batteries.
    Flooded (wet-cell) batteries contain a liquid that could spill out if the battery breaks, where sealed batteries only hold enough liquid to allow electrolytes to flow.

    These batteries require regular maintenance to function optimally, need to be charged more often and can’t be placed on their sides during installation to prevent leaking.
    Flooded batteries tend to have a shorter lifespan than sealed batteries.

    Another thing to remember about lead acid batteries are that you need space for them out of sight, as they are bulky and won’t do anything to improve your home decor.
    Lead acid batteries are reliable and therefore great for both off-grid systems or as a backup for those power emergencies we know so well.
  • Lithium ion batteries. Newer and fancier than lead acid batteries, these are improving rapidly thanks to the electric car industry. This is also the kind of battery used for your iPhone and laptop.
    These batteries need minimal maintenance, they can store more energy in a smaller space than lead acid batteries and they have a longer lifespan.

    The biggest drawback of lithium ion batteries is that they are considerably more expensive than lead acid batteries.
    As they don’t take up as much space, lithium ion batteries are a good option for residential use.
  • Flow batteries. These batteries are named for the water-based electrolyte liquid that flows between two separate parts of the battery. They are fairly new on the market and rising in popularity.

    These low-maintenance batteries have a lifespan of up to 30 years, but they are expensive and too large for residential use. They are however an option for large-scale solar systems.
  • Nickel cadmium batteries. These are extremely durable and once again most suited for large scale operations. They are actually extremely toxic which makes them difficult to dispose of.

Factors to consider when choosing a battery

The folks at give the following tips to make you feel less clueless about shopping for solar batteries:

What you want to powerWhat to look for in a battery
The majority of your homeHigh power rating
An energy-intensive applianceHigh instantaneous power rating
Battery power for a long time periodHigh usable capacity
More power in less spaceLithium-ion nickel manganese cobalt batteries
A battery that can be cycled the most amount of timesLithium iron phosphate (LFP) batteries
Highest possible safety ratingLFP batteries

Confused? Here’s a quick breakdown of what the above factors refer to:

Power rating – this tells you how many kW of power the battery can provide at once. This allows you to work out how many and which appliances your battery can power at the same time.  

Instantaneous power rating – some batteries have both a continuous power rating and an instantaneous power rating. The latter lets the battery provide more power in short bursts.

This is a handy quality to power, for example, an appliance that needs a lot of power to turn on, but then runs at a lower power.

High usable capacity – this refers to the amount of electricity the battery is able to store, measured in kilowatt-hours. This number thus informs you how long your battery can provide power to parts of your home.

Lastly, a battery’s chemistry, the primary compound that’s used to store electricity in the battery, determines many of the battery’s qualities and is therefore valuable to keep in mind.

how solar batteries work (1)

How do solar batteries work?

If you are thinking of going completely off-grid, installing solar panels is only the first step.

AGL Discover gives an easy-to-understand breakdown of how your solar system and batteries work to keep your lights on and your business running:

From the sun to your batteries

The sun shines on your solar panels → Solar energy travels through the solar inverter as DC (direct current) where it gets converted into AC (alternating current) for everyday use → The switchboard now sends the solar energy to your appliances to keep them running → Excess energy gets directed to the battery inverter which converts it into a form of storable energy → Energy gets stored in the battery until needed.

From your batteries to your appliances

When the sun stops shining, solar panels stop generating energy and your household switches to the stored battery energy → The battery converter changes the energy into a form that your appliances can use → The switchboard sends the energy to your appliances → You enjoy solar electricity until the battery’s charge runs out.

You have to love the fact that solar batteries let you be more independent from the grid. This reduces your electricity bill, and allows you to continue living your life during loadshedding.

But that’s not all. There are plenty of benefits to be enjoyed from using solar batteries: 

  • You will be doing your bit for our planet. Energy from the grid is produced by burning fossil fuels. Energy from the sun is pollution-free and renewable, which means we can never run out. 
  • It beats using a generator by far. No need to spend extra to feed it fuel, and no excessive noise is produced.
  • With solar power you are in control of the amount you spend on electricity. Going completely off-grid will require a sizable investment from your side, but pays for itself in time.
  • A solar system increases the value of your property.
  • The peace of mind that you will get from knowing you have power available can significantly reduce your stress levels, especially if you are running a business or working from home.

How long do solar batteries last?

Your solar system will have your back for a long time. There are individual differences, but solar panels will on average perform optimally for about 25 years. 

The batteries have a slightly shorter lifespan, at anything between five and 15 years. As noted earlier, different types of batteries have different lifespans, but the way you use them also plays a role.

Be wary of heavy use and continuous deep discharging of your lead acid batteries as this could drastically reduce their lifespan. 

Ask about this when you purchase your batteries, so that you can be advised on the most efficient way to use them. 

Regarding the actual usage period, the average storage time for a battery in a home solar system is estimated at three times your daily usage. So you should get three days of power from your solar batteries.

Bottom line

Think about that moment the power goes off. It’s infuriating, even the times when you knew it was going to happen.

Solar power is not going anywhere. Society is becoming increasingly aware of the importance of living green, and here’s the best part: solar power is getting cheaper.

If you can’t afford it now, keep an eye on the industry and get it when you can. Keep your lights on and your sanity intact.

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