Parasitic drain in Automobiles
Parasitic drain is the sudden discharge of power(Voltage) from the battery due a short circuit or a turned on switch or appliance while the vehicle engine is turned OFF.
Parasitic drain test is carried out at Key Off Engine Off(KOEO).
Tools required for the Test
1. Multimeter
2. A clamp down Plyer
3. Alligator clips
Test sequence
1. Connect Plyer to -ve battery terminal
2. Connect alligator clip to Plyer and terminal head
3. With readings set to Amps connect multimeter in series with battery -ve terminal
4. With reading set to voltage, measure voltage drop across each fuse in the vehicle.
Test validation
1. Not more than 50milliamp across the amps meter on the negative terminal of the battery
2. Not more than 0.0 Volts across the voltage meter on the fuse
Test description
By design the vehicle requires battery power(voltage) of about 12.6V or more to start the engine, though this depends on the vehicle starting current by design, any power(Voltage) less than this will not start the vehicle. If a clients complain is that his battery is not able to start his vehicle in the morning or after being parked for awhile, this means that the vehicle electricel system is experencing a Parasitic Drain.
The implication is that there is a short to power or ground on the electrical control system of a particular circuit or some circuits, which leaves the system ON while the vehicle engine is turned Off. The vehicle is designed in such a way that the battery power(voltage) is recharged by the alternator when the engine is running.
Parasitic drain test is performed in two steps, the first step is to confirm the amount of power(voltage) in the battery with the use of the multimeter connected across the battery treminals, after that is done, with all the appliances Off and all door shut, disconnect the negative terminal of the battery, connect a multimeter in series(Bear in mind that the reading should be in amps) and allow the system control modules to shut down this occurs after 30sec of being inactive.
Observe the reading on the multimeter, it should not be more than 50milliamps. Any reading more than 50milliamps implies the vehilce has a parasitic drain.
While the multimeter is still connected in series to the negative battery terminal, with another multimeter measure the voltage drop across each of the fuses in all the fuse boxes available in the vehicle, the valve should not be more than 0.0 volts. Any reading more than 0.0 volts implies that circuit has voltage drop.
Another way to get this done is by disconnecting all the fuses one after the other and monitor the amp reading on the multimeter connected in series with the negative terminal of the battery, if an increase or decrease in amp reading is observered, it impies that the removed fuse controls is the faulty circuit.
Ensure that your multimeter reading is set to Amperes and Voltage respectively when conecting the multimeter in series with the negative terminal of the battery or over the fuses.
The test light can not give valid information with respect to this test.
Once the faulty circuit is located, narrow down to the cause before replacement of any component, relay, fuse or battery.
Knowledge in Power…
Information processing is the key to acquiring knowledge
Your thought pattern is the key to your ability to processing information effectively. THINK!!!
Parasitic drain is the sudden discharge of power(Voltage) from the battery due a short circuit or a turned on switch or appliance while the vehicle engine is turned OFF.
Parasitic drain test is carried out at Key Off Engine Off(KOEO).
Tools required for the Test
1. Multimeter
2. A clamp down Plyer
3. Alligator clips
Test sequence
1. Connect Plyer to -ve battery terminal
2. Connect alligator clip to Plyer and terminal head
3. With readings set to Amps connect multimeter in series with battery -ve terminal
4. With reading set to voltage, measure voltage drop across each fuse in the vehicle.
Test validation
1. Not more than 50milliamp across the amps meter on the negative terminal of the battery
2. Not more than 0.0 Volts across the voltage meter on the fuse
Test description
By design the vehicle requires battery power(voltage) of about 12.6V or more to start the engine, though this depends on the vehicle starting current by design, any power(Voltage) less than this will not start the vehicle. If a clients complain is that his battery is not able to start his vehicle in the morning or after being parked for awhile, this means that the vehicle electricel system is experencing a Parasitic Drain.
The implication is that there is a short to power or ground on the electrical control system of a particular circuit or some circuits, which leaves the system ON while the vehicle engine is turned Off. The vehicle is designed in such a way that the battery power(voltage) is recharged by the alternator when the engine is running.
Parasitic drain test is performed in two steps, the first step is to confirm the amount of power(voltage) in the battery with the use of the multimeter connected across the battery treminals, after that is done, with all the appliances Off and all door shut, disconnect the negative terminal of the battery, connect a multimeter in series(Bear in mind that the reading should be in amps) and allow the system control modules to shut down this occurs after 30sec of being inactive.
Observe the reading on the multimeter, it should not be more than 50milliamps. Any reading more than 50milliamps implies the vehilce has a parasitic drain.
While the multimeter is still connected in series to the negative battery terminal, with another multimeter measure the voltage drop across each of the fuses in all the fuse boxes available in the vehicle, the valve should not be more than 0.0 volts. Any reading more than 0.0 volts implies that circuit has voltage drop.
Another way to get this done is by disconnecting all the fuses one after the other and monitor the amp reading on the multimeter connected in series with the negative terminal of the battery, if an increase or decrease in amp reading is observered, it impies that the removed fuse controls is the faulty circuit.
Ensure that your multimeter reading is set to Amperes and Voltage respectively when conecting the multimeter in series with the negative terminal of the battery or over the fuses.
The test light can not give valid information with respect to this test.
Once the faulty circuit is located, narrow down to the cause before replacement of any component, relay, fuse or battery.
Knowledge in Power…
Information processing is the key to acquiring knowledge
Your thought pattern is the key to your ability to processing information effectively. THINK!!!
