Tesla has confirmed it will unveil a revolutionary power pack for the home next week . The California firm said it will announce a 'home battery ' and a 'very large utility scale battery ' in a letter sent to investors . While products such as this already exist , founder Elon Musk thinks they 'suck ' , according to Tesla 's investor relations director , Jeff Evanson . Scroll down for video . The California firm said it will announce a 'home battery ' and a 'very large utility scale battery ' in a letter sent to investors . The company already offers battery packs ( pictured ) for its SolarCity project , but it is unclear whether the latest product will build on this design . There are a number of home battery packs on the market . Most work by powering up overnight when electricity rates are cheaper . Users can then switch them on during the day to use the home during the day . They can be used as back up power in the case of an emergency , or be used to hold power from renewable energy sources . Home battery packs could disrupt the utility market . In 2013 , the Edison Electric Institute , the trade group for investor-owned electric companies , issued a report warning about disruption . 'One can imagine a day when battery storage technology or micro turbines could allow customers to be electric grid independent , ' the report said . Musk announced the event last month in a cryptic tweet that said there will be a launch of a 'major ' new line of products that is 'not a car ' . The event will be held at Tesla 's Hawthorne , California , Design Studio on April 30 at 8pm . PT . ' [ At the event ] we will explain the advantages of our solutions and why past battery options were not compelling , ' the company said . Home batteries power up overnight when electricity rates are cheaper . Users can then switch them on during the day to use the home during the day . In February , Musk said their version of a home battery would be ready for a public debut within months and that it should start going into production by the summer . It is likely to build on the power packs used in Tesla 's range of electric cars such as the Model S. 'We are going to unveil the Tesla home battery , the consumer battery that would be for use in people 's houses or businesses fairly soon , ' Mr Musk told analysts earlier this year . 'We have the design done , and it should start going into production in about six months or so . ' He did n't reveal what a home battery would be used for , but it could act as a generator during a power cut , for example . While products such as these already exist , founder Elon Musk ( left ) thinks they 'suck ' , according to Tesla 's investor relations director , Jeff Evanson . On the right is an image of a Tesla residential battery being installed . Tesla 's billionaire founder last month fuelled speculation by saying it 'not a car ' and added the product will be revealed at the company 's California , Design Studio on April 30 at 8 p.m. PT . But at a conference last year , Tesla 's Stationary Energy Storage Director Arch Padmanabhan revealed some of Tesla 's initial plans . The Mirai features the Toyota Fuel Cell System , which combines fuel cell technology with hybrid technology . The firm said it can serve as a 'high capacity power supply during emergencies ' . The Mirai converts the DC power from the CHAdeMO power socket in the boot to AC power , using an attachment . Toyota calls it a vehicle-to-home system . Tesla 's home battery could work in a similar way , or be a standalone battery . This included a 400 kWh commercial/utility battery for large buildings and a 10 kilo-Watt hour residential battery . Rival car manufacturer Toyota already uses a hydrogen fuel cell in its Mirai car that can be removed and used to power a home . According to the Japanese car maker , the battery can supply electric power to an average home for a week . Last year , Tesla Motors unveiled plans for a 'Gigafactory ' designed to help the firm ramp up production of batteries for its electric cars , and now homes . Tesla said the factory will cut current battery production costs by up to 30 per cent , and will be powered predominantly by renewable energy sources , such as wind and solar . Elsewhere , Mr Musk is already the chairman of SolarCity - a company that offers solar power systems for homes - and Tesla 's home battery could be an extension of this . These batteries 3ft tall ( 0.9 metres ) , and can be controlled remotely using a smartphone app . Tesla would not comment on whether the new batteries will work in the same way . Home battery packs could disrupt the utility market . In 2013 , the Edison Electric Institute , the trade group for investor-owned electric companies , issued a report warning about disruption . 'One can imagine a day when battery storage technology or micro turbines could allow customers to be electric grid independent , ' the report said .
Event will be held at Tesla 's California Studio on April 30 at 8pm PT . Battery is likely to build on the packs used in Tesla ’ s electric cars . While similar products already exist , Mr Musk has said they 'suck ' Toyota already uses a fuel cell in its Mirai car that can power a home .