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Charging Guides

How charging works and how to work out the time yourself. Written to go with the charging calculators.

  1. EV Charging Levels Explained: Level 1 vs Level 2 vs DC Fast

    Level 1, Level 2 and DC fast charging compared: voltage, power, miles of range per hour and how long each takes to add 50 kWh to an electric car.

  2. How to Calculate EV Charging Time by Hand

    The EV charging time formula: battery kWh times the percent you add, divided by charger kW times efficiency. A worked example, the onboard charger limit and common mistakes.

  3. EV Charging Curve: Why Fast Charging Slows Down After 80%

    Why DC fast charging slows down as an EV battery fills, why 10-80% is the charge time most people quote, and how to plan stops around the charging curve.

  4. What Size Home EV Charger Do You Need?

    16, 24, 32, 40 and 48 amp home EV chargers compared: kW at 240 volts, the circuit each one needs under the 80% continuous load rule, and how long each takes to add 50 kWh.

  5. How Long to Charge a Car Battery (12 V Car, RV and Boat Batteries)

    How long it takes to charge a 12 volt car, RV or boat battery: the amp-hour formula, a 100 Ah example on a 10 amp charger, and why the last 20-30% of a lead-acid charge is slow.

  6. Lithium vs Lead-Acid Battery Charging

    How lithium and lead-acid batteries charge differently: efficiency, safe charging current, charge stages, full charge time and depth of discharge, with 100 Ah examples.

  7. Capacitor Time Constant (RC): Charge and Discharge Explained

    The RC time constant explained: τ = R x C, why a capacitor reaches 63.2% in one time constant, the 5τ rule, a table of charge and discharge percentages and worked examples.

  8. How Long to Charge a Battery With a Solar Panel

    How long a solar panel takes to charge a 12 volt battery: watt-hours needed, peak sun hours, system losses, and PWM vs MPPT charge controllers, with a 100 Ah and 200 W example.