Home energy storage systems, meaning large batteries used as buffer storage in residential buildings, are becoming increasingly important in light of growing photovoltaic installation numbers and the desire for energy independence. At the same time, many electric cars from earlier model years are nearing the end of their lifespan. This naturally raises the question: Can a Tesla battery be used as a home energy storage system?
Tesla battery for photovoltaics
Anyone with a solar panel on their roof can cover their own electricity needs when the sun is shining. But in darkness or bad weather, they quickly become reliant on energy from the grid. The solution: a battery that charges when there is excess energy production (sunshine) and continues to supply the house with power independently when needed (darkness).
This system is neither new nor particularly innovative, but it's already in use millions of times. The problem so far: the batteries used are usually quite small due to high unit costs. It would be practical if a discarded Tesla battery could be used as a PV storage system.
Tesla Powerwall – a proven system
First of all: There is already a Tesla battery as a PV storage system; it operates under the name... “Powerwall“. These are not old electric car batteries, but a brand-new system from Tesla. A sophisticated battery management system, integration with the Tesla Home app, numerous safety features, and a 10-year warranty are among the advantages.
However, even the Tesla Powerwall, with its 13.5 kWh capacity, is far from being a car battery and costs at least 6.450 € Including VAT and installation, it's not exactly a bargain.
Used Tesla battery as home storage
So it is an old Model 3 battery after all (z.B. Can you put a 78 kWh (long-range version) electric car in your garage? It's possible! However, this is not a DIY project for children.
In principle, Tesla batteries are well-suited for this purpose: they are plentiful, have been tested millions of times, and, especially as LFP batteries (Model 3/Y), are also thermally very stable and therefore comparatively safe. Thanks to the increasing number of Model S and 3 vehicles that are getting on in years, these batteries are now also quite easy to acquire.
Here you can read about the Condition of an older Tesla It stops after 160,000 kilometers driven.
Between 5,000 and 7.000 € You should get a battery pack; in addition, a new battery management system and a hybrid inverter are needed. Both are readily available online. However, the services of a high-voltage certified electrician are absolutely essential and not available online. – Building your own home is life-threatening.
This results in total costs between 10.000 € and 15.000 €. That's about the same as for a larger "off-the-shelf" product (Powerwall), except that the available capacity is many times greater when building your own.
This advantage comes at a price: no one can guarantee a DIY solution, and the home insurance company is likely to have a say in the matter, given the newly evaluated fire risk.
