Battery Converter
Battery figures are quoted in different currencies and different units depending on who is writing. This turns any of them into the ones you use.
Enter a price, say what unit it is per, and choose what you want it shown as. The result appears in eight currencies at once. Example: a price quoted at 1,000 US dollars a tonne, shown in euros per kilogram.
Type into any box and the others fill in. Nothing is fetched from anywhere, so these work even if you are offline.
Capacity to energy
You have a battery rated in ampere-hours and want to know how much energy it holds. Pick the voltage, or type your own.
Why you have to give a voltage. Ampere-hours measure how much electric charge a battery holds, not how much energy. Two batteries both rated 100 Ah can hold very different amounts of energy if they run at different voltages. Multiply the two together and you get watt-hours, which is energy. Voltage also drifts as a battery empties, so the figure on the label is a nominal average rather than an exact one.
Energy per kilogram
How much energy a battery carries for its weight. Research papers use megajoules; the industry uses watt-hours.
Per kilogram is not per litre. One watt-hour is exactly 3,600 joules, so the conversion never changes. But watch which one you are reading. Watt-hours per kilogram is energy for a given weight. Watt-hours per litre is energy for a given space. Both get called energy density and they are not the same thing. Weight matters in a car, space matters in a phone.
Power
Watts, kilowatts, megawatts and gigawatts. Used for chargers, factories and grid projects.
Power is a speed, energy is a quantity. Watts tell you how fast energy moves. Watt-hours tell you how much there is. A tap and a bucket: watts are how fast the water runs, watt-hours are how much you end up with. So a 100 MW storage project and a 100 MWh one are different things, and a project quoted only in MW does not tell you how long it can run for.
Weight
Tonnes, kilograms, pounds and both kinds of imperial ton. Materials data is quoted in all of them.
Three different tons. A metric tonne is 1,000 kg and is what the USGS and the IEA publish. A US short ton is 2,000 pounds, about 907 kg. An imperial long ton is 2,240 pounds, about 1,016 kg, and still turns up in older commodity contracts. The gap between the smallest and the largest is around 12 per cent, which is enough to change a conclusion.
The official daily rates published by the European Central Bank, shown against the US dollar. The small line on each card is the last month.
Where the rates come from. These are the European Central Bank's daily euro reference rates, retrieved through Frankfurter, an open service that republishes ECB data. The ECB publishes them once each working day at about 4pm Central European Time. At weekends and on holidays the most recent published rate is shown, and the date of the rate in use appears above.
What these rates are not. A reference rate is an official daily snapshot for accounting and statistics. It is not a tradeable quote, not a live market rate, and not the rate a bank will give you, which includes a margin. Do not use this tool to price a transaction, settle a contract or value a position.
We do not publish prices. This tool converts a figure that you type in. The Battery Ledger holds and republishes no commodity, metal or battery price data. No lithium, cobalt, nickel or lead price appears here, and none is implied by any figure shown or by the example in the price box.
The unit conversions are exact. They are fixed by definition and calculated in your browser, so they work whether or not the rate feed is reachable. One watt-hour is exactly 3,600 joules. One tonne is 1,000 kilograms. One pound is exactly 0.45359237 kilograms. One short ton is 2,000 pounds. One long ton is 2,240 pounds. Results are rounded for display, so a figure converted and converted back may differ in the last digit.
Nothing here is financial, investment or trading advice. Figures are for general orientation and should be checked independently before any commercial use. Data source: European Central Bank via Frankfurter. To report an error, email editor@thebatteryledger.com.