This thought crossed my mind but I don't have enough information to come to a conclusion. This assumption is based upon the fact that the tail lights are the same as the license plate light (I'm assuming there is only one). My current light bulbs draw about 317 mA of current and for the three (Two tail and one license plate light), it is a total of 951 mA. The new LED light bulbs I have draw 37 mA for a total of 111 mA. Is it possible to gain fuel economy at night by having 840 mA less draw on the 12V battery?
No. If you want to change light bulbs because you like the way they look or the technology that is involved, that's fine. However you will not be able to measure the fuel economy change associated with such a tiny reduction in electric power usage.
Hi FF, I agree with Patrick. To get significant fuel economy change, you need to change a continuous draw by 5 amps or so at 12 Volts. So, if / when good LED headlights come along, that plug into the existing housings, there would be a good change. Right now, those LEDs headlights are much bigger than the opening the halogen bulbs plug into. If you sit in accessory mode for long times at night, your change would result in a longer lived 12 V battery, however. If you came up with dual 1 foot by 6 inch (?) LED light panel headlight you could afix to the front bumper, or hood, and disable the Halogens, it might be practical. You might save half the current. Which would be significant. You would also need light wipers for cold weather operation, as the LEDs wont provide enough heat to melt snow/ice below about 15 F, I would think. So the panels will need 40 F PTC heaters (heats the panel to 40 F, and then shuts down). You could probably get the PTC heaters from scrap Prius Rear View mirrors. It would be expensive, but with the LEDs spread out like that, they should have a long service light, and the size of the panel allows for many LEDs to be used, and thus not have to be run at high currents.
I bought my car used and it's a 2005. I assume I have HID lights on them. How much current do those lights consume?
HID's typically draw 35 watts (~3 amps) each whereas Halogen's draw 55 watts ( 65 watts high beam - that's about 5 amps) each. JeffD
I see your point. I'm reducing the power consumption by about 14 Watts or .02 HP. I'll be able to fly on the highway now....haha!
Yep as pointed out the power needed to push the car along is so very much larger than the power you're saving that you wont see any noticeable effect. I should point out however that at slow speeds like 35 MPH the electric energy to propel the car on level ground is a lot less than 41000 W, more like about 6000W actually. So if you save 10W then it might net you about 0.1% of a percent gain. That's about 0.05 MPG so don't expect to be able to either notice or measure it. If we were able to change all the lights (including the halogen headlights) for LED's we might be able to save about 100 to 120 Watts. This could actually be enough to make a small but perhaps just noticeable increase in fuel efficiency under some circumstance (low speed night time driving). This might actually net you an extra half a MPG.
Yes! This will help your fuel economy. But not much. This is essentially the answer that those pessimists above gave, but don't you feel better?
http://priuschat.com/forums/knowled...andard-optional-equipment-some-countries.html should help you identify what you have. Yes, Xenon headlights == HID. If you have HIDs, the light should be pretty close to white or slightly bluish. Halogens will look orangish. Also, on the HIDs, if you turn the high beams on/off, a mechanism inside moves forward/back. There's no 2nd set of bulbs that comes on. Yep. I don't recall if you bought a ScanGauge but if you did and you monitor Xgauge BTA (HV battery amps in/out), you can see the difference between sitting idle w/headlights off vs. on. Then compare to values likes when you floor the car, try to acclerate on electric only, coast, dead band below 41 mph, etc. You'll see the headlight draw is minuscule.
I wonder if the folks that legislated daytime running lights here did an environmental impact study due to all the extra barrels of oil we burn up here because of it.
I must have HID then. The guy I bought the car from said that I have Xenon light bulbs. They are kind of bluish but I think they suck and aren't bright enough. Any suggestions?
Folks try to tell me that I am wasting gas running the headlights in daytime. Very little 'waste' compared to not being in an accident.
To determine whether you have factory HIDs or not, check your car's equipment level w/the link I referenced. We have no idea what the previous owner(s) did and what they installed. I find that my HIDs are plenty bright but then again, this is my 3rd car in a row w/factory HIDs. I've had rentals w/halogens (and driven my parents' cars w/them) and most suck in comparison. Side note: There is a potential problem w/factory HIDs pointing downwards. http://priuschat.com/forums/gen-ii-...headlights-pointing-almost-straight-down.html is a thread I dug up but I doubt it's the most current on this issue.
I checked in that thread and I actually have package #4 (I originally thought #2) for the 2005 Prius, which is the AM package, which has HID lights installed.
