Interior illumination dims? Battery issue?
Interior illumination dims? Battery issue?
The other day i was driving at night and i notice in the corner of my eye the climate and radio illumination would dim whenever my trans shifts or rpm drops near idle. My car starts fine, doesn't hesitate but i do recall sometimes the battery will work fine like that but when you do a quick amperage draw it will fail on its ass. My old 2003 4runner had a original Panasonic battery which worked and started fine but since the 4runner has a electric brake booster (which draws alot of current) my headlights used to dim when it engages and recharges the assist. My 4runner battery never did die, i ended up replacing the battery anyways and then i noticed the problem when away. Im wondering if my Fit's battery is showing signs of that weakness.
Member
Joined: May 2012
Posts: 1,671
From: Boston, MA
I know when I apply the brakes my headlights dim. I mostly notice this when sitting in the driveway; while driving there's too much going on to notice.
My older cars never used to do this. I don't think this is a design flaw though. I think it was considered acceptable. I'll just say this: In a Land Rover, I suspect this would not be considered acceptable. I'm OK if a Japanese subcompact has lower standards for 50% of the average US new-car cost!
My older cars never used to do this. I don't think this is a design flaw though. I think it was considered acceptable. I'll just say this: In a Land Rover, I suspect this would not be considered acceptable. I'm OK if a Japanese subcompact has lower standards for 50% of the average US new-car cost!
I know when I apply the brakes my headlights dim. I mostly notice this when sitting in the driveway; while driving there's too much going on to notice.
My older cars never used to do this. I don't think this is a design flaw though. I think it was considered acceptable. I'll just say this: In a Land Rover, I suspect this would not be considered acceptable. I'm OK if a Japanese subcompact has lower standards for 50% of the average US new-car cost!
My older cars never used to do this. I don't think this is a design flaw though. I think it was considered acceptable. I'll just say this: In a Land Rover, I suspect this would not be considered acceptable. I'm OK if a Japanese subcompact has lower standards for 50% of the average US new-car cost!
Member
Joined: Aug 2012
Posts: 1,199
From: Vermont, USA
It's perfectly normal behavior. When the engine is idling, the alternator cannot put out too much electricity, so the car's electrical system is running mostly off the battery. The battery's voltage when discharging is always going to be lower than the voltage required to recharge it (such as happens when the engine is running at speed). Possibly the interior illumination circuitry of the Fit is more sensitive to voltage differences than in some other vehicles for some reason, making the voltage variations more immediately obvious, but within reason they're nothing to be concerned about.
It's perfectly normal behavior. When the engine is idling, the alternator cannot put out too much electricity, so the car's electrical system is running mostly off the battery. The battery's voltage when discharging is always going to be lower than the voltage required to recharge it (such as happens when the engine is running at speed). Possibly the interior illumination circuitry of the Fit is more sensitive to voltage differences than in some other vehicles for some reason, making the voltage variations more immediately obvious, but within reason they're nothing to be concerned about.
The part i find odd is, it doesn't do it with things like turn signals working which you'd think would fluctuate voltage, it seems to do it mostly when the transmission shifts up a gear or when rpm drops below 2500 which it does when it shifts. But if I let it sit at a stop light with signals on doesn't even faze it which boggles me. How much power does a trans solenoid suck up during a shift? I don't ever notice my buddies fit do this and we both have 2012 sport models.
Banned
Joined: Feb 2013
Posts: 1,361
From: right coast
Honda electrical systems are engineered to run at the lowest voltage output from the alternator to save fuel from lower drag from the alternator. When the ELD (electrical load detector) senses that the voltage is too low it allows the alternator to produce more. BUT while it should be instantaneous it really take a beat or two to catch up.
Perfectly normal operation for a modern Honda.
Perfectly normal operation for a modern Honda.
Running all your accessories can take output voltage down a full volt.
I was playing with that the other day with the FlashPro. Radio, headlights/foglights/fan/compressor/defroster and the occasional rad fan flicking on and off could bring it from ~14.40-50 at warm idle to 13.30.
Easily enough to see the change in your headlights, and I would wager the dash too.
I was playing with that the other day with the FlashPro. Radio, headlights/foglights/fan/compressor/defroster and the occasional rad fan flicking on and off could bring it from ~14.40-50 at warm idle to 13.30.
Easily enough to see the change in your headlights, and I would wager the dash too.
Honda electrical systems are engineered to run at the lowest voltage output from the alternator to save fuel from lower drag from the alternator. When the ELD (electrical load detector) senses that the voltage is too low it allows the alternator to produce more. BUT while it should be instantaneous it really take a beat or two to catch up.
Perfectly normal operation for a modern Honda.
Perfectly normal operation for a modern Honda.
I wonder if this is why the battery on the fits always take a crap.
Member
Joined: Dec 2011
Posts: 782
From: WV
From Honda's FAQ on owner's website:
Is it normal for my headlights to dim slightly and then come back to normal while my car is stopped at a light?
This is a normal characteristic and is caused by variations in the electrical system created by the onboard computer. The computer controls the output of the electrical charging system to improve fuel economy and minimize vehicle vibration.
While the engine is at idle, the computer monitors the electrical usage of the car and then controls the electrical charging system so that it charges just enough to keep up with demand. This change reduces the load on the engine and, in turn, increases fuel economy and reduces vehicle vibration. As electrical accessories turn on and off, the computer changes the rate of electrical charge in response to the changes in demand for electricity. As the computer responds to the addition of electrical load, you may notice a momentary dimming of the lights. For example, the headlights or instrument panel lights may briefly dim as the air conditioning cycles on.
This is a normal characteristic and is caused by variations in the electrical system created by the onboard computer. The computer controls the output of the electrical charging system to improve fuel economy and minimize vehicle vibration.
While the engine is at idle, the computer monitors the electrical usage of the car and then controls the electrical charging system so that it charges just enough to keep up with demand. This change reduces the load on the engine and, in turn, increases fuel economy and reduces vehicle vibration. As electrical accessories turn on and off, the computer changes the rate of electrical charge in response to the changes in demand for electricity. As the computer responds to the addition of electrical load, you may notice a momentary dimming of the lights. For example, the headlights or instrument panel lights may briefly dim as the air conditioning cycles on.
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