Headlight Flicker
11-03-15, 05:10 PM
#33
Lead Lap
1) I think every new vehicle is known for severe battery drain issues. Its way too many electronics to control everything that basically cannot ever be fully "asleep".
2) In regards to flicker, have you had condensation in the headlight unit? That would be my first Troubleshoot area. Then onto the harness and its connectors.
3) Intermittent problems are a PITA. You as the customer will notice it, but cant do anything to fix it. Warranty/SAs either claim its in your head or magically the car will fix itself and then they cannot do anything LOL
2) In regards to flicker, have you had condensation in the headlight unit? That would be my first Troubleshoot area. Then onto the harness and its connectors.
3) Intermittent problems are a PITA. You as the customer will notice it, but cant do anything to fix it. Warranty/SAs either claim its in your head or magically the car will fix itself and then they cannot do anything LOL
11-03-15, 05:47 PM
#34
I was an electronic technician in the Air Force. It was a long time ago, but electricity hasn't changed. Let me address some of the below. Please note that all of the comments have been cross-checked to either a reliable source of electrical engineering or an auto enthusiast site or LED manufacturer's website.
Things are measured in power, which is measured in watts. Joules are a measure of power over time, also called "energy", similar to measures like watt-hours. A joule is also the energy used when an electric current of one ampere passes through a resistance of one ohm for one second. A formula for power is P=IR, meaning power (in watts) = current (in amperes) times resistance (in ohms). Light bulbs and LEDs and almost everything else is rated in watts, as this is how much power they use when operating. One watt is the rate at which work is done when one ampere of current flows through an electrical potential difference of one volt.
Correct, but not the only formula applicable here. We also need Current (amps) = Voltage / Resistance (ohms) and Power (watts) = Voltage^2 (^2 = squared) / Resistance (ohms).
Listening...
Incorrect. A typical starter motor's resistance is about 0.04 ohms. As such, it requires 300 amps (12 volts / .04 ohms = 300 amps) to run (the starter in question was a Ford. Sorry Chevy people!). This, by the way, uses 3600 watts of energy (12^2 / .04).
(Note: some of the following is a bit oversimplified for those who are not electrical engineers or the like).
LEDs do not have typical "resistance" since they and other diodes are not "Ohmic resistors" (whereas a regular incandescent light bulb is an ohmic resistor). Rather than having a resistance, they have an "I-V characteristic curve". To avoid having to understand this curve, think of it as a "turn-on voltage" (call it TOV). If the actual voltage is less than the TOV, no current will flow through the LED. If the actual voltage is more than the TOV, resistors inserted in series will control the current such that the voltage drop across the diode is exactly the TOV. Each diode's operating voltage will be a particular range of volts; this information can be found on an LED's "data sheet". In auto applications they often start well below 12V. A typical headlight I found was labeled as "Input Voltage: 9V-32V" and uses 15 watts of power.
This 7-minute video is a good learning tool about the I-V (current-voltage) curve:
No. As your battery dies it loses the ability to push current (in amperes) at its rated voltage (as its own internal resistance increases). Yes, eventually the battery's voltage will decline, especially when measured under load, but a typical battery (of almost any kind) will deliver current at the rated voltage across upwards of 85% of its charge.
Bottom line: if the battery won't turn over the starter the LEDs probably will still work. If the LEDs don't work the starter hasn't a chance.
Correct, but not the only formula applicable here. We also need Current (amps) = Voltage / Resistance (ohms) and Power (watts) = Voltage^2 (^2 = squared) / Resistance (ohms).
LEDs do not have typical "resistance" since they and other diodes are not "Ohmic resistors" (whereas a regular incandescent light bulb is an ohmic resistor). Rather than having a resistance, they have an "I-V characteristic curve". To avoid having to understand this curve, think of it as a "turn-on voltage" (call it TOV). If the actual voltage is less than the TOV, no current will flow through the LED. If the actual voltage is more than the TOV, resistors inserted in series will control the current such that the voltage drop across the diode is exactly the TOV. Each diode's operating voltage will be a particular range of volts; this information can be found on an LED's "data sheet". In auto applications they often start well below 12V. A typical headlight I found was labeled as "Input Voltage: 9V-32V" and uses 15 watts of power.
This 7-minute video is a good learning tool about the I-V (current-voltage) curve:
As your battery dies, the voltage decreases. Thus V=IR changes. You go for your starter, now your battery has 6V, well if the low current is enough to operate the starter (as R is constant) the starter will turn. However, with a lower current (as R is constant for the LEDs as well) you may not be able to support the current required to operate the lights.
Thus, as the batteries die, their ability to operate the "super efficient" LEDs is impacted by inconsistent current and potential loss of lights. They are efficient for long term on the alternator (alternator use is what impacts gas mileage), but their dependence on the initial battery is high.
Last edited by 15RC350F; 11-04-15 at 04:51 AM.
11-03-15, 07:35 PM
#35
Lexus Test Driver
Thread Starter
I was an electronic technician in the Air Force. It was a long time ago, but electricity hasn't changed. Let me address some of the below. Please note that all of the comments have been cross-checked to either a reliable source of electrical engineering or an auto enthusiast site or LED manufacturer's website.
Things are measured in power (which in the Metric system is joules, but in the English system is watts). P=IR, meaning power (in watts) = current (in amperes) times resistance (in ohms). Light bulbs and LEDs and almost everything else is rated in watts, as this is how much energy (power) they require to operate.
Correct, but not the only formula applicable here. We also need Current (amps) = Voltage / Resistance (ohms) and Power (watts) = Voltage (squared) / Resistance (ohms).
Listening...
Incorrect. A typical starter motor's resistance is about 0.04 ohms. As such, it requires 300 amps (12 volts / .04 ohms = 300 amps) to run (the starter in question was a Ford. Sorry Chevy people!). This, by the way, uses 3600 watts of energy (12^2 / .04).
(Note: some of the following is a bit oversimplified for those who are not electrical engineers or the like).
LEDs do not have typical "resistance" since they and other diodes are not "Ohmic resistors" (whereas a regular incandescent light bulb is an ohmic resistor). Rather than having a resistance, they have an "I-V characteristic curve". To avoid having to understand this curve, think of it as a "turn-on voltage" (call it TOV). If the actual voltage is less than the TOV, no current will flow through the LED. If the actual voltage is more than the TOV, resistors inserted in series will control the current such that the voltage drop across the diode is exactly the TOV. Each diode's operating voltage will be a particular range of volts; this information can be found on an LED's "data sheet". In auto applications they often start well below 12V. A typical headlight I found was labeled as "Input Voltage: 9V-32V" and uses 15 watts of power.
This 7-minute video is a good learning tool about the I-V (current-voltage) curve: LED Tutorial: Plotting the IV Curve for a 10W LED - YouTube
No. As your battery dies it loses the ability to push current (in amperes) at its rated voltage (as its own internal resistance increases). Yes, eventually the battery's voltage will decline, especially when measured under load, but a typical battery (of almost any kind) will deliver current at the rated voltage across upwards of 85% of its charge.
Bottom line: if the battery won't turn over the starter the LEDs probably will still work. If the LEDs don't work the starter hasn't a chance.
Things are measured in power (which in the Metric system is joules, but in the English system is watts). P=IR, meaning power (in watts) = current (in amperes) times resistance (in ohms). Light bulbs and LEDs and almost everything else is rated in watts, as this is how much energy (power) they require to operate.
Correct, but not the only formula applicable here. We also need Current (amps) = Voltage / Resistance (ohms) and Power (watts) = Voltage (squared) / Resistance (ohms).
Listening...
Incorrect. A typical starter motor's resistance is about 0.04 ohms. As such, it requires 300 amps (12 volts / .04 ohms = 300 amps) to run (the starter in question was a Ford. Sorry Chevy people!). This, by the way, uses 3600 watts of energy (12^2 / .04).
(Note: some of the following is a bit oversimplified for those who are not electrical engineers or the like).
LEDs do not have typical "resistance" since they and other diodes are not "Ohmic resistors" (whereas a regular incandescent light bulb is an ohmic resistor). Rather than having a resistance, they have an "I-V characteristic curve". To avoid having to understand this curve, think of it as a "turn-on voltage" (call it TOV). If the actual voltage is less than the TOV, no current will flow through the LED. If the actual voltage is more than the TOV, resistors inserted in series will control the current such that the voltage drop across the diode is exactly the TOV. Each diode's operating voltage will be a particular range of volts; this information can be found on an LED's "data sheet". In auto applications they often start well below 12V. A typical headlight I found was labeled as "Input Voltage: 9V-32V" and uses 15 watts of power.
This 7-minute video is a good learning tool about the I-V (current-voltage) curve: LED Tutorial: Plotting the IV Curve for a 10W LED - YouTube
No. As your battery dies it loses the ability to push current (in amperes) at its rated voltage (as its own internal resistance increases). Yes, eventually the battery's voltage will decline, especially when measured under load, but a typical battery (of almost any kind) will deliver current at the rated voltage across upwards of 85% of its charge.
Bottom line: if the battery won't turn over the starter the LEDs probably will still work. If the LEDs don't work the starter hasn't a chance.
11-03-15, 07:44 PM
#36
11-05-15, 11:58 AM
#39
Things are measured in power, which is measured in watts. Joules are a measure of power over time, also called "energy", similar to measures like watt-hours. A joule is also the energy used when an electric current of one ampere passes through a resistance of one ohm for one second. A formula for power is P=IR, meaning power (in watts) = current (in amperes) times resistance (in ohms). Light bulbs and LEDs and almost everything else is rated in watts, as this is how much power they use when operating. One watt is the rate at which work is done when one ampere of current flows through an electrical potential difference of one volt.
Power is the rate of energy consumption. In metric units, power is measured in watts (W) and energy is measured in joules. A watt is equal to one joule per second (1 W = 1 J/s). Therefore, P=IV (where P = power, I = current in amperes, and V = voltage in volts). Alternatively, using Ohm's law, P=I²R.
@15LexNX2 seems to have a good understanding of electrical principles so I think this was just a typo or mix-up. :P
No. As your battery dies it loses the ability to push current (in amperes) at its rated voltage (as its own internal resistance increases). Yes, eventually the battery's voltage will decline, especially when measured under load, but a typical battery (of almost any kind) will deliver current at the rated voltage across upwards of 85% of its charge.
Last edited by computerwi; 11-05-15 at 12:03 PM.
11-05-15, 12:50 PM
#40
11-06-15, 03:50 AM
#41
Lexus Test Driver
Thread Starter
Nothing again today, so I'm going to probably put this thread to rest. I can't help but think that my driver size headlight is not as bright as my passenger, but I think its a placebo effect in which I'm "looking" for something to be wrong as opposed to it really being wrong. The car has 7001 miles on it now. Barring anything else going wrong, I'll make sure to mention that I want them to look at it when I go in for 10,000.
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