I was wondering one of those totally esoteric things on the way home the other day and thought I would throw it out to the group. Might anyone know if or by how much turning your headlights on in the dayime affects MPG's? It would seem to me they should since it requires electrical power to power the lights and that in turn should mean that the batteries will need to be charged more often. Is this correct and if one was to keep them his lights all the time, in rain and shine, could it also have any effect on the life of the batteries? Would there be any difference for foglights or HID's? Side note; I still can't figure out why Toyota has not tied their headlights to the wiper system. Seems like common sense.
<div class='quotetop'>QUOTE(Scott_W @ Apr 12 2006, 12:39 PM) [snapback]238588[/snapback]</div> Headlights use power. There is no free lunch, so using your headlights reduces your MPG, unless, of course, you only use them when the car is in regen braking and your batteries are charged (I added this technical case to avoid being nitpicked). It's not much power, especially with HIDs, so it's not going to be a big hit like it is with air conditioning. If you want to figure out how much, take the wattage of the lights and multiply it by the conversion efficiency of the ICE/MG. Tom
hmmm well 2 bulbs dosnt do that much i think,,, around a 100Watts ?? anyone ? i think the rest of the electronic in the car uses much much more.....electric steering, brakes ,, pumps u name it HID uses usually less when beeing used (i think 35Watts compared to a 55Watts halogen bulb, unless You use a more powerfull HID system). HID uses more when they "ignite" , but this is just for a short period of time... (else i recomend driving the same direction as the wind goes,, should be much more effectfull,sure that will give some real challenges sometimes.......hmmm maybe i could put a sail on too :blink: )
Do a search. I remember someone here posting what items used how much power. I recall seeing that the rear defroster uses the most power.
Halogen lights will use around 50-65 watts per. I'm in Canada so my lights are on all the time. 100 watts isn't all that much power. Coasting a few blocks would probably give you all the power you would consume with the lights for the entire trip. I'm not too worried about that kind of consumption since my entertainment system is sucking down 700 watts constantly.
Having Daytime Running Lights (DRLs) does tend to add an extra edge of safety that can't really be measured in miles per gallon. After riding behind DRLs, I'm a little disappointed that my HID-equipped Prius doesn't allow me to use the fog lights as DRLs. I know there are a few mods for the fogs, but most tend to allow their use with parking lights, which I don't want to do. (The dash and MFD dim, for one thing, when the parks are on.) I'm keeping my eye out for a straight DRL fog mod.
hmm? I thought the foglight mod was independent of the headlight switch. In other words, you can leave your foglight switch in the ON position and it'll turn off when you open the driver's door.
Did I misread the mod? There was so much talk of parking+fogs, or hi-beams+fogs that perhaps I got confused. Time to look again...
<div class='quotetop'>QUOTE(Rick Auricchio @ Apr 12 2006, 09:44 PM) [snapback]238961[/snapback]</div> When the Parking lights or headlights are on, If you turn the dimmer switch all the way up, then the MFD and instrument cluster will return to full brightness. The thing that scares me is that if you turn the dimmer all the way down, the instrument cluster turns off! no spedometer!
<div class='quotetop'>QUOTE(engunneer @ Apr 13 2006, 10:31 PM) [snapback]239599[/snapback]</div> Yes, but to get the fogs on you have to turn on the headlights. That would burn the HIDs way more than makes sense. And DRLs usually don't light the tail lights, do they?
<div class='quotetop'>QUOTE(engunneer @ Apr 13 2006, 10:31 PM) [snapback]239599[/snapback]</div> Yeah. At night it seems like it goes directly from "too bright" to "gone"! <div class='quotetop'>QUOTE(Tideland Prius @ Apr 12 2006, 09:48 PM) [snapback]238964[/snapback]</div> Nope. You need to have at least the parking lights on even with the mod.
Well, leaving the headlights on for an hour would cost about two green car icons from the regen braking. Dennis
Note that leaving the headlights on all the time will also likely force you to change your headlight bulbs more frequently. I did the headlights-always-on thing in my old car and the lights burned out after a few years. DRLs use the high beams to distribute the work to the bulbs that you rarely use. -Euge
<div class='quotetop'>QUOTE(Euge @ Apr 14 2006, 10:38 PM) [snapback]240066[/snapback]</div> That is so true! I leave mine on all of the time and have had to replace both halogen units at less than 30,000 miles.
<div class='quotetop'>QUOTE(Euge @ Apr 14 2006, 10:38 PM) [snapback]240066[/snapback]</div> In the case of the HID bulbs, I figure bulb replacement could be fairly expensive.
<div class='quotetop'>QUOTE(seasalsa @ Apr 15 2006, 08:47 AM) [snapback]240119[/snapback]</div> For my Celica with DRL, I replaced the H7 low beams at 59,700 miles. Both of them went dead at the same time! It costs $20 to replace both and it was pretty easy. I even got the bulbs that's 30% brighter bulbs. If Prius headlights last 30,000 miles, I don't mind changing them at all =D I leave mine always on. Dennis
The HID replacement bulb costs about US$124 at my Toyota dealer, whereas a halogen bulb is about US$10. So you can see why I don't want to burn the HIDs during the daytime as DRLs.
Couple of things: HID is more expensive... they should also last quite a bit longer than halogen. HIDs also consume less energy. The energy needed to keep the lights on is *insignificant* as compared to the traction power, so I wouldn't even blink an eye about that. Hey - I even use headlights on my EVs without worrying about it! The fog mod does require the parking lights to be on... they also all turn off/on automatically when the car is shut down (so if you WANT the parking light on when parked, you have to power cycle them). The most important exterior lighting problem I can think of is those dim tail lights! 5W. They're the dimmest taillights on the road, and I seriously worry about my safety from behind in bad weather. The Prius just disappears. Every followed one in the rain or fog?
Are there any stats for longevity of the HID bulbs? I would expect that each ignition takes a toll, similar to what happens with fluorescent lamps. I'm not...that's a non-issue, as you say. I may go that route, but I'd really prefer "ignition hot" fogs, so I don't have to fool with dash brightness. The most important exterior lighting problem I can think of is those dim tail lights![/quote]The tail lights are important, of course, but not as important as brake lights---which seem plenty bright. I wonder why the quotes didn't work on the preceding message? They look correct to me.
