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Tesla’s top-of-the-range battery storage system is still one of the most expensive on the market. It has a huge 13.5kWh usable capacity and can even keep you up and running during a power cut. But how long does a Tesla Powerwall battery last? And does this mean it’s worth investing in one?

The Tesla Powerwall 2.0 comes with a 10-year warranty. But Tesla says that it should last way beyond this – at least 5 years longer. The standard warranty says that it should work at 70% capacity for the full 10 years – so if it loses more than 30% of its storage capacity within that time, it should still be covered.

While the Tesla Powerwall does last a long time, it has a large capacity that most average households won’t require, and it’s a costly option. After installation, the Powerwall 2.0 will set you back between £6,500 and £9,000, so ideally you want it to last past its 10-year warranty.

Before you splash out, consider the size of the solar panel system you want to install or you already have. Will it generate enough electricity to make it worth storing in the Powerwall? If not, are you expecting to upgrade your solar panels to a larger system in the future? If you are, then it might be worth investing in a Powerwall. It might also be better to wait until you come to upgrade your solar panels – the solar battery price trend is going the same way as solar panels, so they will probably continue to decrease in price as more people adopt the technology.

Most people want to connect solar panels to a battery when they’re not at home all day to use the electricity they generate, or generate more than they consume over a day. Solar batteries are a great way to maximise the savings on your energy bills since you can use every unit of electricity you generate.

If you want to connect your solar panels to a battery, the best – and safest – way is to ask an MCS-registered company to do it for you. They’ve had lots of training and hold qualifications in handling electricity and installing solar batteries, so they will be able to recommend the best battery for your solar panels and for the among of electricity you use. Some of the brands they might recommend include Tesla, SolarEdge and SolaX, but there are many more to choose from. If you want to send electricity to the grid from your battery to receive Smart Export Guarantee (SEG) payments, it’s also worth leaving installation up to a registered installer. This is because you might not be eligible for payments if your battery wasn’t installed by an MCS-registered company.

However, if you do want to have a go at connecting your solar panels to a battery, it’s worth finding out whether your system is ‘storage ready’. Most relatively new systems will be, since batteries are becoming more commonplace. If your solar panels are storage ready, they will have an inverter that can easily have a battery added to it. If this is the case, then you should be able to buy the solar battery you want and follow the manufacturer's instructions to install it.

But it’s worth remembering that electricity is extremely dangerous when handled improperly. If you don’t get the solar battery connected properly and something goes wrong, it could cause a fire or you could electrocute yourself. If a fire breaks out due to your battery, it’s unlikely that your home insurance company would pay out since you connected the battery yourself. That’s why it’s always worth speaking to a registered installer to install a solar battery storage system for you.

Solar panels provide an alternative to paying expensive National Grid energy rates, so primarily their first major benefit is helping to reduce bills. Solar PV panels will produce free electricity, whilst solar thermal panels generate heat for hot water and space heating. There are also payment incentives known as the Feed-in Tariff scheme (FITs) (for solar PV) and the Renewable Heat Incentive (for solar thermal) which guarantee a tax-free income for 20 years.

The lifetime of a solar panel depends on its quality and age. Generally, the older a solar panel gets, the less efficient it becomes. The majority of modern solar panels come with 20-30 year warranties, which means that they’ll stay at a good efficiency level for at least this long. Some panels can stay efficient for as long as 40 years, while others won’t last this long.

There are two different types: flat plate, where lots of thin tubes carry water through a flat absorber panel, and evacuated tube, where vacuum glass tubes capture the sun’s energy directly. There is little difference in performance between the two but evacuated tube panels do more obviously extrude from the roof.

It’s vital to purchase a solar panel system that suits your property. If you’re investing in a solar panel system, it makes the most financial sense to get the biggest one possible. However, whether you can do this or not depends on budget and space.

Here’s an idea of how much roof or ground space you’ll need to install a few different sizes of commercial solar panel system.

Solar panel system size, No. of solar panels, Approximate area required

11kW, 44, 64m²

20kW, 80, 116m²

30kW, 120, 173m²

40kW, 160, 231m²

50kW, 200, 288m²