What is the voltage of a laptop charger?
For mobile phones and other mobile devices like the Kindle that charge with USB, the voltage is typically 5V. A laptop charger might be as high as 20V or 25V. You can usually find the voltage your device needs on the device itself, on the battery, or if all else fails, on the manufacturer's web site.
You could use a Lightning connector plugged into a computer (via USB), an iPhone charger connected to a wall socket, or an iPad charger connected to a wall socket. A PC USB charger delivers 2.5 Watts of power (5 volts at 500 mA). An iPhone charger delivers 5 Watts (5 volts at 1000 mA).
- Using Ohms law, you would multiply amperage times volts to get watts. For instance a 12 volt circuit drawing 2 amps would consume 24 watts of power (12*2=24). A 60 watt light bulb powered by 120 volts in a house would draw .5 amp of current (60/120= .5).
- It is possible, however, to deduce from the web page Apple created “Charge the battery in your iPad,” that Apple is aware of this capability and endorses it. Simply increasing the current from .5 amps (USB charging cable) or 1 amp (the bundled iPhone charger) to 2.1 amps (the iPad charger) boosts the charging speed.
- Assuming You have a typical full size auto battery, it is about 50 amp hours. To Calculate how much time You'll need to charge the battery with a 15 Watt solar charger You'll need: Calculate the Ampere per hour of the charger: 15 Watts /12 Volts = 1,25 Amperes.
Updated: 2nd October 2019