The history
225 years from a stack of metal discs in Italy to the battery box that keeps India's fans turning when the power goes out.
A battery gives steady, one-way direct current, but homes and grids run on alternating current that flips back and forth many times a second. For a hundred years the only way to turn one into the other was with spinning machines or glowing glass tubes. Then silicon switches arrived, and a small box could store power in a battery, turn it back into AC and take over in a blink when the mains failed. In India, where power cuts were part of daily life, that box became the home inverter, and now lithium batteries and rooftop solar are changing it again.
1800
Battery giving a steady current
Alessandro Volta, Italy
1859
Rechargeable battery
Gaston Planté, France
1884–85
Efficient closed-core transformer
Zipernowsky, Bláthy and Déri, Hungary
1902
Mercury-arc rectifier
Peter Cooper Hewitt, USA
1957
Commercial thyristor (SCR)
General Electric, USA
1969
Large thyristor UPS for a computer in Japan
Fuji Electric, Japan
1984
APC's first UPS for PCs
American Power Conversion, USA
1991
Commercial lithium-ion battery
Sony, Japan
1800 – 1882
Scientists learn to make a steady current from chemicals, then build the first battery that can be charged again and again.
1800
20 March 1800
Volta stacked discs of zinc and copper with cloth soaked in salty water between them. The pile gave a steady electric current, something no one had made before. He described it in a letter to Joseph Banks, president of the Royal Society in London, dated 20 March 1800.
Why it mattered. For the first time people could store electricity in chemicals and let it out as a steady current, just as an inverter battery does.
1831
29 August 1831
Faraday wound two coils of wire around an iron ring. When he switched the current in one coil on or off, a current jumped into the other coil for a moment. Only a changing current could do this.
Why it mattered. This is how a transformer works, and a home inverter still uses one to lift the battery's low voltage up to mains voltage.
1859
Planté rolled two sheets of lead into a spiral, kept apart by strips of rubber, and dipped them in dilute sulfuric acid. When the battery ran down, he could push current back in to charge it again. It was the first rechargeable battery.
Why it mattered. The lead-acid battery is still the heavy box sitting next to most home inverters in India.
1881
Planté's batteries took a long time to prepare. Faure pressed a paste of lead oxide into a lead grid, which held far more charge and was much quicker to make. Factories could now build lead-acid batteries in large numbers.
Why it mattered. Pasted plates descended from this idea are still inside many inverter batteries today.
1882 – 1900
Edison's direct current fights Westinghouse and Tesla's alternating current. Transformers let AC travel far, and AC wins the grid.
1882
4 September 1882
Edison's Pearl Street Station began sending 110-volt direct current through cables under the streets of lower Manhattan. It started with 82 customers and 400 lamps. But low-voltage DC loses a lot of power in the wires, so it could only reach a short distance.
Why it mattered. It showed the problem that AC would solve, and DC is still what every battery stores.
1885
1884–1886
At the Ganz works in Budapest, three engineers built efficient transformers with closed iron cores, known as the ZBD transformer. In March 1886 William Stanley, backed by George Westinghouse, used ideas from these designs to run a demonstration AC lighting system in Great Barrington, Massachusetts.
Why it mattered. Transformers let AC be sent at high voltage and stepped down safely, which DC could not do.
1888
1 May 1888
Tesla, a Serbian-American engineer, was granted US patents for motors driven by a rotating magnetic field made from AC. In Italy, Galileo Ferraris had built a similar motor on his own. In July 1888 George Westinghouse paid to license Tesla's patents.
Why it mattered. Once AC could run motors as well as lights, it had everything it needed to win the grid.
1893
1 May 1893
Westinghouse won the contract to light the Chicago World's Fair with alternating current, underbidding General Electric. By some counts about 200,000 lamps glowed across the grounds. Tesla showed his motors and generators at the Westinghouse exhibit.
Why it mattered. Millions of visitors saw that AC could light a whole city safely.
1896
26 August 1895 and 16 November 1896
The Adams hydroelectric plant at Niagara Falls started making AC power in August 1895. On 16 November 1896, power was sent more than 20 miles to the city of Buffalo. It was the first long-distance transmission of hydroelectric power in the United States.
Why it mattered. It settled the war of the currents: the grid would be AC, so a battery's DC must be inverted to use it.
1888 – 1960
To turn AC into DC and back, engineers use motor-generators, rotary converters and mercury-arc tubes. Flywheels give the first backup power.
1888
Bradley's rotary converter was a spinning machine that took in AC and gave out DC for trams, trains and factories. Run the other way, such machines could turn DC into AC. That is where the word ‘inverter’ comes from: an inverted converter.
Why it mattered. For half a century, turning one kind of current into the other meant a big machine spinning in a room.
1902
Cooper Hewitt found that an electric arc in mercury vapour inside a glass bulb lets current flow only one way. His mercury-arc rectifier turned AC into DC without moving parts. It was used to charge batteries and run trams and trains, and later to send power under the sea.
Why it mattered. A rectifier is the charger half of every inverter: it turns mains AC into DC to fill the battery.
1955
1954–1955
Batteries for telephone and radio equipment needed daily care and wore out in a few years. Fuji Electric built a prototype uninterruptible power supply in 1954 and was delivering units by 1955. A heavy flywheel spun on a motor-generator, and when the mains failed, its momentum kept the generator turning.
Why it mattered. The goal of every UPS was already clear: no gap at all when the power goes out.
1947 – 1990
The transistor, the thyristor, the power MOSFET and the IGBT replace moving parts. Silent static UPS systems protect the first computers.
1947
16–23 December 1947
Bardeen and Brattain made a tiny crystal device that could amplify a signal, and showed it to their bosses on 23 December 1947. Shockley soon designed an improved version. The three shared the 1956 Nobel Prize in Physics.
Why it mattered. A switch with no moving parts made possible every electronic inverter that followed.
1957
1956–1957
Building on ideas from Shockley and Bell Labs, a GE team made the silicon controlled rectifier, or thyristor. A tiny pulse at its gate could switch a large current on. GE introduced it in 1957, and in 2019 the IEEE named it a Milestone.
Why it mattered. It started the move from spinning machines and glowing tubes to solid-state inverters.
1969
Fuji Electric built a 200 kVA power supply with a large three-phase thyristor inverter and delivered it to a Fujitsu computer plant. It had no spinning flywheel, so it was smaller and could go almost anywhere. Static UPS systems like this spread to guard mainframe computers around the world.
Why it mattered. Battery, charger and thyristor inverter together made the modern static UPS.
1978
1969–1978
In 1969 Hitachi showed the first vertical power MOSFET, and in the 1970s Nishizawa's power transistors went into Yamaha amplifiers. In 1977 Lidow and Herman invented the HEXFET at Stanford, and International Rectifier sold it from 1978. These switches can turn on and off many thousands of times a second.
Why it mattered. Fast, cheap MOSFETs are what many home inverters use to chop battery DC into AC.
1982
1982–1985
Baliga, who studied at IIT Madras, showed a working insulated-gate bipolar transistor at GE in 1982. It is as easy to control as a MOSFET but can handle much bigger currents. Nakagawa's team at Toshiba stopped it from ‘latching’ on, and Toshiba sold that design from 1985.
Why it mattered. IGBTs switch the big currents in large UPS systems, solar inverters and electric cars.
1974 – today
Lithium-ion batteries win a Nobel Prize, get far cheaper, and join rooftop solar panels to store sunshine for the night.
1974
early 1970s
Whittingham, an English chemist working for the oil company Exxon, made a battery with a titanium disulfide electrode that lithium ions could slip in and out of. It worked, but its lithium metal side could catch fire, and Exxon gave it up.
Why it mattered. It proved lithium could store a lot of energy in a small, light battery.
1980
Goodenough and his team, including the Japanese scientist Koichi Mizushima, used lithium cobalt oxide for the positive electrode. It gave a much higher voltage than Whittingham's battery and was stable in air.
Why it mattered. A stronger cathode made a powerful lithium battery possible.
1985
Yoshino paired Goodenough's cathode with a carbon anode made from petroleum coke. Lithium ions shuttle between the two sides, and there is no raw lithium metal to catch fire. It was the first commercially practical lithium-ion design.
Why it mattered. It is the basic recipe of almost every lithium battery today.
1991
Sony began selling the world's first rechargeable lithium-ion batteries, based on Yoshino's design. They were light and held a lot of energy, perfect for camcorders, then phones and laptops.
Why it mattered. Lithium-ion began its journey from gadgets to cars to home backup batteries.
1997
1996–1997
In Goodenough's lab, the graduate student Akshaya Padhi and his colleagues found that lithium iron phosphate could serve as a cathode. They published it in 1997. Iron is cheap and plentiful, and the material stays stable even when it gets hot.
Why it mattered. LFP batteries last thousands of cycles and are safer, so they now fill most home and grid storage.
2019
9 October 2019
The three scientists shared the Nobel Prize in Chemistry for developing the lithium-ion battery. Goodenough was 97, the oldest person ever to win a Nobel Prize.
Why it mattered. The prize honoured a battery that now powers phones, cars and home backup.
2024
13 and 29 February 2024
India launched PM Surya Ghar: Muft Bijli Yojana, a plan worth ₹75,021 crore to help about 1 crore (10 million) households put solar panels on their roofs. Families can get up to 300 units of free electricity a month. Every rooftop system needs an inverter to turn the panels' DC into AC.
Why it mattered. The inverter is changing from a power-cut backup into the heart of a home solar system.
2025
9 December 2025
BloombergNEF's yearly survey found the average lithium-ion battery pack fell to $108 per kilowatt-hour, 93% cheaper than in 2010. Packs for stationary storage, like home and grid batteries, were the cheapest of all at $70. Lithium iron phosphate packs averaged $81, well below other kinds.
Why it mattered. Lithium batteries are becoming cheap enough to replace lead-acid next to the home inverter.
By the numbers
BloombergNEF's yearly average pack price. Each point is in real dollars of the year it was reported; the 2010 point is BNEF's figure restated in real 2025 dollars.
1981 – 2012
UPS boxes shrink to sit under a desk, and in India the home inverter, a battery plus charger plus inverter, becomes a household must-have.
1984
Three engineers from MIT's Lincoln Lab founded APC in 1981 to work on solar power. When government solar funding dried up, they made their first UPS in 1984, the model 750, with a lead-acid battery inside. It kept personal computers and small networks running through blackouts.
Why it mattered. The UPS shrank from a room-sized machine to a box under a desk.
1988
Malhotra, an electronics engineer from Jadavpur University, started Luminous with about Rs 40,000 of savings, four people and 600 square feet of space. It first made power backups for computers, then home inverters from 1994. In 2011 Schneider Electric bought a 74% stake.
Why it mattered. Indian companies designed inverters for Indian homes, with long, frequent power cuts.
1998
Sachdev had run a cable TV equipment business since the late 1980s. In 1998, seeing how often the power went out, he turned Su-Kam to power backup. Su-Kam made inverters with plastic bodies instead of metal ones and went on to export to more than 90 countries.
Why it mattered. Home inverters became as ordinary in Indian homes as the fan and the fridge.
2012
30–31 July 2012
On 30 July the northern grid failed, cutting power to over 400 million people. The next day three regional grids collapsed and over 620 million people lost power, about 9% of everyone on Earth. Homes with charged inverters could keep a few fans and lights on.
Why it mattered. It showed why so many Indian families keep a battery and inverter ready.
Did you know?
The word ‘inverter’ comes from an ‘inverted converter’: early machines that turned AC into DC could be run backwards to turn DC into AC.
On 31 July 2012 more than 620 million people in India lost power at once, about 9% of the world's population.
Luminous began in 1988 with four people, 600 square feet of space in South Delhi and about Rs 40,000 of savings.
John Goodenough was 97 when he won the Nobel Prize in Chemistry, the oldest Nobel laureate ever.
In 2025, battery packs for stationary storage averaged $70 per kWh, cheaper than packs for electric cars.
The people
1745 – 1827 · Physicist · Italy
Built the voltaic pile, the first battery to give a steady current.
1834 – 1889 · Physicist · France
Invented the lead-acid battery, the first that could be recharged.
1840 – 1898 · Chemical engineer · France
Pasted lead oxide onto grids so batteries could be mass-produced.
1856 – 1943 · Engineer and inventor · Austrian Empire (today Croatia) and USA
Patented AC motors that helped alternating current win the grid.
1860 – 1939 · Electrical engineer · Hungary
Co-inventor of the ZBD transformer at the Ganz works in Budapest.
1861 – 1921 · Electrical engineer · USA
Invented the mercury-arc rectifier that turned AC into DC with no moving parts.
born 1948 · Electrical engineer · India and USA
IIT Madras graduate who developed the IGBT at General Electric.
born 1941 · Chemist · England and USA
Made the first lithium rechargeable battery of its kind in the 1970s.
1922 – 2023 · Materials scientist · USA
Found the lithium cobalt oxide cathode and led the lab that found lithium iron phosphate.
born 1948 · Chemist · Japan
Designed the first commercially practical lithium-ion battery.
born c. 1962 · Engineer and founder · India
Started Luminous in 1988 and built it into a major inverter brand.
born 1962 · Entrepreneur · India
Turned Su-Kam from cable TV to inverters in 1998, and is called the ‘Inverter Man of India’.
Where it happened
Sources
Dates marked “c.” are approximate, and historians sometimes disagree about who was first. If you spot a mistake, tell us.
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