For How Long Can a Car Battery Charge a Cell Phone?

For How Long Can a Car Battery Charge a Cell Phone?

Car batteries are available even in the most remote places. With a 12-volt adapter, these batteries can charge your phone. Knowing how long you can use the battery to keep charging your phone requires some basic math skills.

How Powerful Is The Battery
Car batteries deliver a steady 12 volts, but the current varies according to the design of the battery. Batteries are rated in amp-hours, describing how many amps the battery will deliver over a set period of time. High amp-hour batteries last longer than low amp-hour batteries.

How Much Power Does The Charger Use?
Phone chargers draw power from the battery and convert it to a voltage suitable for the phone. Putting power into the phone necessitates taking power out of the battery, and the faster the power is taken, the quicker the battery is discharged.

Typical Charger Power Usage
Research conducted at the Lawrence Berkeley National Laboratory shows a mobile phone charger, while charging a phone, uses an average of 3.68 watts. Current equals wattage divided by voltage, so the average phone charger is drawing 0.3 amps from a 12-volt battery.

How Long Will The Battery Last?
A fully charged 200 amp-hour battery will, in theory, deliver 20 amps for 10 hours or 2 amps for 100 hours. The charger draws 0.3 amps, so the battery will run the charger for a maximum of 666 hours ((20/0.3) amps * 10 hours). Due to inefficiencies in batteries, the actual time will be about 2/3 of this: 444 hours.

How to Replace a 12-Volt Power Outlet

How to Replace a 12-Volt Power Outlet

A 12-volt power outlet has been commonly used to power a cigarette lighter, usually mounted in the dash panel of your vehicle. Now, traditional 12-volt power outlets have given way to outlets designed to charge your mobile phones or power your MP3 players. They are the same 12-volt power outlets used in older cars, only the manufacturer opts not to give you the cigarette lighter with them now. Replacing the 12-volt power outlet is the same on new cars as it is on older cars.

Things You'll Need
Socket set
Screwdrivers
Pliers or adjustable wrench



Instructions
Remove the dash panel to which your 12-volt outlet secures. In general, you need a Phillip's screwdriver and/or a socket set to remove the plastic panels on the dashboard. Every make and model uses a slightly different process for installing the dash panels. If necessary, refer to the vehicle repair manual for your vehicle make and model if the bolt locations for the dash panel are not easily located.

Disconnect the wiring harness that plugs into the back of the 12-volt power outlet. The harness has a small lock on the side. Push in on the lock and pull the harness off the outlet.

Remove the jam nut that secures the outlet to the plastic dash panel using a pair of pliers or an adjustable wrench.

Slide the power outlet through the front of the dash panel by pushing on the back of the power outlet.

Slide the new power outlet through the face of the dash panel and secure it by tightening the jam nut with your pliers or adjustable wrench.

Push the wire connector onto the back of the 12-volt power outlet.

Reinstall the dash panel onto the vehicle.