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However, battery capacity can also be expressed in milliamp hours (mAh), watt hours (Wh) and kilowatt hours (kWh). So you'll often see this formula written with these units: charge time = battery capacity (Ah) ÷ charge current (A) Most often, your battery's capacity will be given in amp hours (Ah), and your charger's charge current will be given in amps (A). The easiest but least accurate way to estimate charge time is to divide battery capacity by charge current. Formula 1įormula: charge time = battery capacity ÷ charge current I start with the simplest and least accurate formula and end with the most complex but most accurate.
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3 Battery Charging Time Calculation Formulasįor those interested in the underlying math, here are 3 formulas to for calculating battery charging time. Click "Calculate Charge Time" to get your results. If your battery is dead, you'd enter 0.Ħ. For instance, if your battery is 20% charged, you'd enter the number 20. Optional: Enter your battery state of charge as a percentage. Select your battery type from the list.ĥ. Depending on the combination of units you selected for your battery capacity and charge current, the calculator may ask you to input a voltage.Ĥ. If the calculator asks for it, enter your battery voltage or charge voltage. The unit options are milliamps (mA), amps (A), and watts (W).ģ. Enter your battery charger's charge current and select its units from the list.
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The unit options are milliamp hours (mAh), amp hours (Ah), watt hours (Wh), and kilowatt hours (kWh).Ģ. Enter your battery capacity and select its units from the list. Tip: If you’re solar charging your battery, you can estimate its charge time much more accurately with our solar battery charge time calculator.
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