How many hours will a solar battery last

You’ve got the solar and now you would like to add a battery, but how many hours will a solar battery last?  This is one of the questions that is often asked when looking into purchasing a storage battery to add to your solar system.

Why add a solar battery?

Adding battery storage to your solar system is a great way to become even less reliant on the grid and save more on your energy consumption bills.  The excess energy that is produced during the day by your solar system is then stored in the battery for use at night or for protecting your home from blackouts.  

If you are not exporting much excess energy to the grid, then the suitability of a solar battery for your system may not be recommended.  Before purchasing a solar battery, consideration is made regarding the amount of energy you are producing with your solar system, how much you are using and how much you are sending back to the grid.  These calculations will assist in determining the size of the solar battery that will suit your particular needs.

Battery types

There are three types of solar batteries available – lithium-ion, lead acid and saltwater.   Lithium-ion solar batteries are the longest lasting of the three options.  The lifespan can be anything from 5 to 15 years, check on the manufacturer’s warranty.  They are the most popular choice of solar battery at present.  

Lead acid batteries are good for off grid systems and are possibly the least expensive option, but they don’t hold their charge as long as lithium batteries. 

Saltwater solar batteries are the newest available and are recyclable, but are bulky and pretty much untested still in the market.

Depth of discharge

As with mobile phone batteries, the amount of times you charge and discharge your battery will affect the amount of time it holds its charge.  Your solar battery will be able to run a cycle of charging and discharging a certain amount of times, depending on the make and capacity.   In other words, the more you cycle a battery the less it will be able to hold it’s charge and the sooner it will reach the end of its functional life.  

Every solar battery has instructions from the manufacturer as to the depth of discharge (DoD) that the battery should be run down to.  For example, if you have a 10kW battery and you use 8kW of its charge, you have a depth of discharge at 80%.  It is important to note what the manufacturer recommends as far as depth of discharge is concerned, as using your battery beyond its limits will possibly shorten the lifespan of your solar battery.

Single or three phase

Most Aussie homes are on a single phase electrical system.  Very large homes with ducted air conditioning and a pool pump will  normally be on a three phase circuit.  Most solar batteries are suited to single phase or will normally only supply power to the circuit it is connected to in the case of a three phase home.

What are you running on it?

If you generally want to run a few lights, fridge and a TV, a battery with 5kW capacity should last about 10 hours.  If you add the use of heavy duty energy guzzlers for example air conditioners or a pool pump, it is going to drain the solar battery very quickly.  

This is why it is important to know what kilowatts of continual power the battery is going to produce and to know which appliances you require to run off the battery at night or during a blackout.


The choice of your solar battery is fairly complex and we recommend the services and advice from a reputable solar company in working out the best solution for your particular needs.  Working out how many hours a solar battery lasts really boils down to knowing the kilowatt performance of the battery and whether you require running your whole home from it or use limited appliances.  One thing for certain is that your reliance on the grid will be less and therefore your normal energy bills will be reduced with the use of a solar battery.   

Cool or Cosy can offer you expert advice and we have a selection of batteries to suit your needs.  Give us a call at Cool or Cosy to receive a no obligation consultation.  We will advise you whether making use of the SA government solar battery scheme and purchasing a solar storage battery is the right solution for your energy needs.

Are you looking for quality solar panels in Adelaide? You have come to the right place. At Cool or Cosy, we supply Australian-made Tindo Solar Panels that are made to suit our climate and are designed and tailored to suit your unique space. With no deposits necessary and an impressive 25-year warranty, going solar has never been this easy, we will guide you through the process. Get in touch with us today to see how we can help reduce your energy bills through innovative solar energy solutions!

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