Headlights affect on fuel mileage?

<div class='quotetop'>QUOTE(likesmpg @ Aug 23 2007, 08:38 PM) [snapback]501286[/snapback]</div>

Does the traction battery power the headlights?

If not, lights on would have a negligible effect on on mileage.

CC

 

<div class='quotetop'>QUOTE(CheepCheep @ Aug 23 2007, 09:09 PM) [snapback]501301[/snapback]</div>

Regardless of which battery the headlights are powered from, that power was generated from the ICE, so the effect is still there, just as headlights on a conventional car are powered from the battery, and that power must be replaced by the alternator, which puts additional drag on the engine, which affects fuel economy. IOW, lights use power, which has gotta come from somewhere.

 

<div class='quotetop'>QUOTE(GeoDosch @ Aug 23 2007, 09:35 PM) [snapback]501311[/snapback]</div>

I agree, and I even go to the extreme of only using my turn signals when necessary. Meaning if I am waiting at a red light, I do not have them on and will put them on when the light turns green. Also, if I am in a designated turn lane I don't have them on as the direction I'll be moving in is already predetermined by the lane. Most importantly, I only run the A/C when my six year old son is in the car as that is the biggest killer of MPG. It's all in the life of a hypermiler.

 

Headlights -- about 200 watts.

As for skimping on turn signals -- please, don't.

 

Hello! Once the relays to the t.batt the a.batt (12V) is no longer used. The inverter supplies the 12V (also charges the a.batt).

side note: hid headlights uses less power than the halogen headlights.

 

<div class='quotetop'>QUOTE(brad34695 @ Aug 23 2007, 06:56 PM) [snapback]501325[/snapback]</div>

No offence but you are one of the sources of my worst driving agrivation! By not turning you turn signals on until the light turns green, no one behind you can have the option of avoiding you by changing to another lane! As I am oft quoted as saying, "Turn signals are for what you are GOING to do rather than what you just DID!"

As the other poster says, PLEASE, for the benefit of all of us, start using the signals. I'll even send you the
$.20 you might save every year!

Icarus

PS My other driving nightmare is the guy not bothering to pass someone while driving in one of the left lanes of the freeway, plugging it up for all the rest of us!

 

<div class='quotetop'>QUOTE(icarus @ Aug 23 2007, 11:11 PM) [snapback]501365[/snapback]</div>

The dreaded "Parcheesi Block" :angry:

 

I always drive with my headlines on (low beam in day) and my battery indicator is usually down about two bars in the blue. Occasionally I check to see if the indicator is green, so I must assume the engine is properly charging ... and use if properly discharging ... the battery as specified. To be sure, while driving a Prius is great fun, and seeing mileage in the 45-55 mpg range over wide terrain, one could easily become distracted looking at the displays and worrying, needlessly, whether one is getting the maximum effort out of the vehicle. My question always is: Am I getting maximum pleasure from driving this car and does it do for me what I expect - get me from Point A to B point efficiently, effectively, and and hopefully safely.

 

The affect would be negligable.
One of those little green cars on the MFD fuel consumption screen repesents enough energy to run your headlights for about half an hour. Running your headlights would have such a tiny affect on fuel consumption that it doesn't justify thinking about.
If you think your headlights should be on, turn them on. If you are changing lanes or turning a corner, use your indicators. The fuel you might save is nothing especially compared to the cost to you and the environment if you have even a minor crash.
If you think your headlights are costing you fuel you should remove the radio and antenna, carpets, gloveboxes, centre consul, rear seats if they don't get used, air conditioning system, etc. All these things use fuel just by being in the car and more if you use the electric components

My personal rules for headlights are: -
If it isn't full daylight headlights on.
If the wipers are on so are the headlights.
If your journey is greater than 100km, headlights on.
If the car is moving you shouldn't have the parking lights on.
Fog lights stay OFF unless there is fog thick enough to affect vision.

 

<div class='quotetop'>QUOTE(brad34695 @ Aug 23 2007, 09:56 PM) [snapback]501325[/snapback]</div>

I think the lack of turn signals is a bit extreme. But if you are going to do that, why not put your car in Nuetral and use the parking brake instead of holding your foot on the brake to avoid the brake lights being on as well? Or does the parking brake engage the brake lights?

 

<div class='quotetop'>QUOTE(tekn0wledg @ Aug 24 2007, 09:37 AM) [snapback]501503[/snapback]</div>

The parking brake does not illuminate the brake lamps, but it does activate the brake warning light on the dashboard.

 

<div class='quotetop'>QUOTE(brad34695 @ Aug 23 2007, 09:56 PM) [snapback]501325[/snapback]</div>

a. I know in NY that is illegal. There is a requirement for how far in advance of a turn you are required to turn on your signal, like 100 feet or something. I expect it is illegal in other states, also.

b. Regardless of the law, safety > mpg. Always. Be predictable and tell others (drivers, cyclists, and pedestrians) what you are going to do before you do it.

 

<div class='quotetop'>QUOTE(nybiker @ Aug 24 2007, 12:23 PM) [snapback]501670[/snapback]</div>

When I was learning to drive, they were refered to as "Turn Indicators" Indicating that you were GOING to make a turn! I believe that's what they're for!

 

<div class='quotetop'>QUOTE(likesmpg @ Aug 23 2007, 08:38 PM) [snapback]501286[/snapback]</div>

Have you looked into the friction powered lights the Amish use on their buggies?

I suspect turn signals are optional equipment that nobody buys because they aren't used.

 

My consideration for not running the headlights all the time is the cost of the HID headlight bulbs. I did see a mod for fixing the fog lamps to run without the headlights so that might be an alternative.

GT

 

Fog lights stay OFF unless there is fog thick enough to affect vision.
Globes last a long time, don't worry about it.
Turning lights on and off shortens the life of globes more than anything.
If fuel consumption is going up with shorter days could it also be cooler weather?

 

I guess for a compromise on the trun singals, you could modify the cadane so they only blink every other blink.

 

Brake lights are LEDs so have very low power consumption. Replace all globes with LEDs to reduce fuel consumption by 0.0000001% Cost of conversion would be about $200 plus labour to replace all incandescent globes (except headlights) with LEDs. Is it worth it? Probably not. If you change indicator globes you may need to use an electronic flasher unit. I'm no expert on these things, feel free to add to this.

 

<div class='quotetop'>QUOTE(EricGo @ Aug 23 2007, 07:19 PM) [snapback]501340[/snapback]</div>

HID headlights are 35 watts each . . . low or high beam.

Agreed on the not skimping on turn signals.