Henri Owen Tudor (30 September 1859 – 31 May 1928) was a Luxembourg engineer, inventor, and industrialist. He developed the first commercially usable lead-acid battery. Life Henri Tudor was the son of John Thomas Tudor from Llanarth (United Kingdom) and Marie Loser from Rosport. He attended the primary and secondary school as a boarder at the municipal College of Chimay (Belgium), and was a student from 1879 to 1883 at the École Polytechnique, which was part of Brussels University. In 1885, the young engineer specialised at an electrical engineering institution in Paris, where he attended the lectures given by Marcel Deprez. Henri Tudor was interested in electricity and especially in its storage. He developed an electric lighting system in his father's residence, the Irminenhof in Rosport, even before he had completed his engineering studies. During his vacations, he connected a Gramme type generator to the water-wheel of the Bannmillen, a mill located on the lower part of the property. Wires carried the electric energy from the mill to the house, which was illuminated with Edison light bulbs. The power supplied by the generator was obviously irregular. Furthermore, it was not used during off-peak hours. Henri Tudor had the idea of using lead acid accumulators as a buffer – to equalise the voltage and to store the unused energy. The chemical reactions occurring in a lead-acid battery or accumulator were first observed by Wilhelm Josef Sinsteden in 1854. The accumulator as a rechargeable battery was invented in 1859 by Gaston Planté and improved in 1880 by Camille Faure. In its practical applications, it proved however to be unreliable: short circuits occurred and the plates fell apart during service. Thomas Edison described the lead-acid accumulator as a "a catch-penny, ... a mechanism for swindling the public" and "commercially ... a failure." Henri Tudor sought a permanent solution to these problems and manufactured himself a mould for casting large surface plates with which he built a lead-acid accumulator of his own design. Doing so, he could rely on the help of his brother Hubert, and of his cousin, Nikolaus Schalkenbach of Trier. With the combined equipment – generator and buffer battery – he was able to run continuously and constantly the power supply of the Irminenhof, which thus became the first private home in Luxembourg to have electric lighting. The Tudor electrode stood out because of its unequalled reliability. We know from a