How to Use a 12-Volt Circuit Tester

How to Use a 12-Volt Circuit Tester

Power is supplied to a vehicle's engine ignition, electric door locks, alarm systems and other accessories by the 12-volt circuitry that runs throughout the vehicle. When a circuit fails, you will find that a 12-volt tester is an invaluable tool for locating the source of the problem. If you are a do-it-yourself auto mechanic who understands basic electrical circuits, you can verify the presence or the absence of electrical power in your vehicle quickly and confidently by using a 12-volt circuit tester.

Things You'll Need
12-volt circuit tester
Maintenance manual


Instructions
Turn on the vehicle's electrical power. The accessory position on the ignition switch powers up everything except the engine ignition circuit. To check the ignition's 12-volt wiring, turn the switch to the "On" position.

Connect the ground clip of the 12-volt tester to a well-grounded source. The battery's negative terminal is the best ground source, but any grounded metal source will do.

Place the pointed end of the tester on or in the circuit terminal or wire to be tested. The point may be used to penetrate the insulation of a wire to make a voltage test if you can't access a terminal. The tester handle lights up if the circuit being tested is in good working condition.

Check the grounding integrity of a circuit by reversing the connections and attaching the ground wire of the 12-volt tester to the positive side of the circuit being tested.

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 Charge Cell Phone Batteries in a Car With an Adapter

How to Charge Cell Phone Batteries in a Car With an Adapter

If you are on the road and notice that your cell phone battery is running low or dead, you can actually charge the phone from the car's own power supply. This is useful for restoring a cell phone battery's life. In addition, you can use the cell phone while the battery is being recharged, which is ideal in emergency situations. The battery will charge safely in the same way it charges when plugged into a regular wall outlet.

Things You'll Need
Vehicle with cigarette lighter or power supply port
Car charger adapter for your model of cell phone
Splitter (optional)
Additional battery and battery charger (optional)

Instructions
Locate a power supply outlet or the cigarette lighter in your vehicle. Some vehicles have multiple outlets, a common place is on the passenger side on the side of the center console. These outlets are often the same size and type as the cigarette lighter one.

Purchase a car charger adapter for your specific make and model of your cell phone. The best way to do this is to order one from your cell phone service provider's website or visit your cell phone service provider's store locations. This will ensure compatibility. You may also want to check the phone's original packaging, as some phones come with a car adapter.

Plug the large end of the adapter into the power outlet or the main cigarette lighter. For the cigarette lighter, remove the handle portion, being careful not to push it in while doing so, as this will heat it up. Place the lighter portion in the ashtray. Ensure it is cool to the touch before placing it in a glove compartment or center console section.

Plug the other end into the cell phone. Wait a few seconds and you should see the battery charging status show up on your cell phone. If you have a cell phone that has a USB connection as the charger, disconnect the USB cable from the original charger by unplugging it and connect it to the car charger adapter.

Purchase a cigarette lighter/car outlet splitter if you need to charge multiple cell phones or devices. You will need to purchase an additional car charger adapter for each additional phone you want to charge.

If you want to charge an extra battery, purchase a battery charger and connect it.

How to Build a Battery Isolator

How to Build a Battery Isolator

Automotive battery charging circuits are designed to recharge and maintain a single battery. However, automobiles with custom audio systems, electric winches or other high-drain devices may require a second battery to power these devices.


One of the problems with connecting two batteries directly to an automotive charging system is that if one battery is weaker (provides less electrical current at the same voltage) than the other, the charging system may be taxed beyond its design parameters for providing power. This also has the undesirable consequence of draining the “good” battery to equalize the charge in both batteries.


One way to charge both batteries without overtaxing the charging system is by using a battery isolator. A battery isolator is constructed using two diodes, which act as one-way electrical check valves for the charging system.



Things You'll Need
Solder-type lug terminals (3)
High-current diodes (two; RF1501TF3S or equivalent – See “Resources”)
Soldering iron
Electronic solder
Electrical wire (insulated copper, minimum 8 AWG thickness)
Electrical pliers
Permanent marker


Instructions
Cut three, 2-foot-long pieces of wire and strip one-half inch of insulation from each wire end.

Solder a lug terminal to one end of the first wire, and mark the side of the lug terminal with the letter “A.” Solder the free end of the first wire to the anode leads on both diodes.

Solder a lug terminal to one end of the second wire, and mark the side of the lug terminal with the number “1.” Solder the free end of this wire to the cathode lead on the first diode.

Solder a lug terminal to one end of the third wire, and mark the side of the lug terminal with the number “2.” Solder the free end of this wire to the cathode lead on the second diode.

How to Charge a Car Battery Through a Cigarette Lighter

How to Charge a Car Battery Through a Cigarette Lighter

An automotive electrical system normally has one or more power accessory points. These accessory points are often cigarette lighter outlets. However, most vehicles manufactured since the 1990s contain dedicated power accessory outlets.


Many automobiles have their cigarette lighter outlets wired so that the outlets only work when the automobiles are running. However, power accessory outlets are usually hardwired to the battery, and are always active.


A power accessory outlet may also be used as a means to trickle charge an automobile battery. Some accessories, such as solar battery chargers, are designed to take advantage of the bidirectional nature of a hardwired power accessory outlet.



Things You'll Need
Automobile with hardwired power accessory outlet
Solar battery charger with automotive cigarette lighter plug


Instructions
Place the solar battery charger, shiny-side up, on the automobile's dashboard.

 A solar charger must have the shiny side (left cell) exposed to light to generate electrical energy.
Plug the battery charger plug into the power accessory outlet.

Allow the battery to charge for approximately six hours, and then unplug the charger from the power accessory outlet.

How to Install a Motorcycle Cigarette Lighter

How to Install a Motorcycle Cigarette Lighter

In general, motorcycles are built to serve as basic transportation. As such, most motorcycles lack features found in even the most basic of automobiles – cup holders, electrical outlets, ashtrays or cigarette lighters, for example.


For some motorcycle riders, it is convenient to have an available power source (such as a cigarette lighter receptacle) to recharge small electronic devices, such as cell phones. A weatherproof DC power outlet can be wired to the motorcycle battery using two wires added to the electrical system.



Things You'll Need
Motorcycle with installed battery
Set of hex wrenches (if motorcycle battery is mounted under the seat)
Screwdriver
Electrical pliers
Red electrical wire (16 AWG or thinner)
Black electrical wire (16 AWG or thinner)
Crimp-style ring terminals (2)
Splice connector terminals (2)
Weatherproof 12V automotive power outlet
Cable ties (three or more)


Instructions
If the battery is installed under the seat, loosen and remove the hex bolts holding the seat in place, and remove the seat from the motorcycle. If the battery is mounted under a side battery cover, pry the battery cover from the motorcycle to expose the battery.

 Some motorcycles have the battery box under a plastic cover near the engine (green triangle, center of photo).
Strip one-half inch of insulation from one end of the black wire and one end of the red wire. Place a ring terminal over the stripped ends of the black and red wires, and crimp the terminals to the respective wires.

Place the positive wire from the weatherproof socket into one of the holes in the first splice connector. Place the free end of the red wire into the splice connector, and crimp the connector to make the electrical connection.

Place the negative wire from the weatherproof socket into one of the holes in the second splice connector. Place the free end of the black wire into the splice connector, and crimp the connector to make the electrical connection.

Loosen and remove the retaining nut on the positive battery terminal. Place the ring terminal attached to the red wire over the terminal screw, and replace and tighten the positive battery terminal retaining nut. Loosen and remove the retaining nut on the negative battery terminal. Place the ring terminal attached to the black wire over the terminal screw, and replace and tighten the negative battery terminal retaining nut.

Route the power outlet to a point on the frame below the rider, and attach the outlet to the motorcycle frame using a cable tie. Use the remaining cable ties to attach the excess wire length to the frame of the motorcycle. Reinstall the battery cover or the seat when finished.

How to Install a New Cigarette Lighter in a Car

How to Install a New Cigarette Lighter in a Car

Most cars produced now days no longer have an actual cigarette lighter inside of the car. The port the lighter uses can still be found in all modern models, but these are now used to power electronic devices. Even if you have an older vehicle you may have burned out the cigarette lighter. If you tend to smoke in your car you may want to look into installing a new cigarette lighter in your vehicle.

Things You'll Need
Replacement cigarette lighter

Instructions
Place the key to your vehicle in the ignition and power on the vehicle. You do not need to start up the ignition, but at least turn the key far enough to start up your radio and power up the windows.

Place an electrical device that uses the lighter charger into the charger to make sure it still works properly. It is possible to accidentally blow out the charger if you have extracted too much power from it at one give point.

Pick up a replacement cigarette lighter. These can be purchased at most automotive stores such as AutoZone or Pep Boys. All cars use the same size so there is no need to measure the size of your power port.

Place the cigarette lighter into the power point. When you want to charge the cigarette lighter press it down completely. Once the lighter is hot enough it is going to pop out. Hold your cigarette against the hot tip for a moment to light the cigarette.