Trough battery spaces between the plates (the troughs) were filled with dilute sulfuric acid. So long as the box was not knocked about, there was no risk of electrolyte spillage. Trough battery The trough battery was a variant of Alessandro Volta's Voltaic Pile and was invented by William Cruickshank c. 1800. Volta's battery consisted of brine-soaked pieces of cloth sandwiched between zinc and copper discs, piled in a stack. This resulted in electrolyte leakage as the weight of the discs squeezed the electrolyte out of the cloth. Cruickshank solved this problem by laying the battery on its side in a rectangular box.
Plug-in electric vehicles in the United States a vehicle which draws propulsion energy from a traction battery with at least 5 kwh of capacity and uses an offboard source of energy to recharge such battery. The tax credit for new plug-in electric vehicles is worth plus for each kilowatt-hour of battery capacity over 5 kwh, and the portion of the credit determined by battery capacity cannot exceed . Therefore, the total amount of the credit, between and , will vary depending on the capacity of the battery (4 to 16 kWh) used to power the vehicles. The qualified plug-in electric vehicle credit phases out for a plug-in