improving mpg's with led taillights?
 

the prius uses led taillights and gets better mpg's (in part)because of it. so can you install led taillights on say a 2010 corolla s and get better mpg's. how much better can you get from installing led taillights? are there led headlights, and how much would that help?

Hi & welcome to EM,

It should make a small difference -- probably way too small to matter. LED headlights would make a bit more of a difference, but still fairly small. The lights are only on part of the time, and they are very low consumption compared to many other things:

Running without A/C makes a large difference. Figuring out how to eliminate the alternator would make a large difference. Making tire pressure and/or aerodynamic improvements will make large differences. And of course your driving techniques can make a large difference.

I doubt it would be a quantifiable difference. You would need to switch every light in the car over to LED, but even then, when are all the lights on loading up the alternator? Not very often. Tail lights, 27 watts each. Brake lights, 45 watts each (only when on of course). headlights, 45-55 watts (depending vehicle) low beam, 55-65 watts high beam. Markers, 9-15 watts each (4 of them on most vehicles). Turn markers, assuming front and rear, 27 watts each, for 4 of them.

So say, 4 turn markers, 4 9W side markers, 2 tail lights, 2 headlights (55W seems more common these days). That's a healthy 308 Watts at approximately 14 volts. But we can do much for the headlights. So ditch that, 110 watts.

So, 198 watts to power the exterior lighting, excluding the headlights. that's around 14 amps draw on the alternator.

Lets swap to LED lighting. Ballparking this, as it would take a while to track down the specific bulbs your car uses, lets assume the 27w replacements use 110mA at our 14 volts. That's roughly 1.5 watts. Soo... high figure it, 2 watts x the 6 27 watt bulbs.

12 watts. Sooo..we removed 5.5 bulbs by switching to LED. Good start. 4 more to go. the 9 watters are 1/3 the power draw, so carry that over, We get 2 watts for all 4. Seems ridiculous to me, so we'll bump it to 4 watts.

Woohoo! Shooting from the hip, generalizing, and using fuzzy math, we have under 20 watts of LEDs compared to 200 watts of incandescent. Even if I'm 100% off on the power draw, that's still only 40 watts.

Okay, we've reduced the load. Now a new problem. The alternator is designed for a certain peak output. It's most efficient at some percentage of that. We're now going way below that. We're now wasting the efficiency of the alternator. We need a smaller one to keep it high. Hmm. Switching to LEDs to save fuel has now cost a ton, for all the LED bulbs to a smaller power supply for higher efficiency. Are you saving money, or just fuel money?

Hope I gave you something to think about. If someone wants to give specifics, go for it. I just generalized power transmission based on the same concepts of the 80+ PSU group for computers. Will swapping all lighting to LED make a significant difference? maybe. But I think changing HOW you drive makes a bigger difference than the design of what you drive. Save the money from the LEDs and use it burning fuel learning how best to drive your car. When you've reached the pinnacle of your efficiency, then start mods to the car's efficiency.

According to my scanguage, When I'm idling with a hot engine & I turn on my headlights fuel consumption goes from .31gph to .36gph. 14% at idle. Going down the road at 1.8 gph that's 2.2%. Yes there will be a difference. Will you ever make up the cost, maybe. If they are common bulbs you may be able to transfer them to another vehicle.

I would start by replacing the bulbs that are on the most, especially if you have daytime running lights.

Don

One thing to also take in to account is Led's have faster response time, which means when you slam on the brakes because some idiot turned in front of you, the car about to rear end you knows sooner. So they have a +1 for safety in my book.

But how much $$$$ do they cost?

KJSatz -

I've heard that for a full replacement, it's maybe $100 to $130. That doesn't include the headlights because no one has made a "strong enough" (or affordable enough?) LED headlight.

CarloSW2

SuperBrightLeds.com has a bunch of drop in replacements for cars. They range from $1.29-$22.95 depending on how bright you want them and what bulb you are replacing.

Something to be aware of with regards to LED bulbs is that there can some issues with dual intensity bulbs and how noticeable the changes are.

For example, most cars have brake light bulbs that when the lights are on, turn on at low intensity and flash at a higher intensity.

Since LEDs really only have 1 brightness level, this has to be given a workaround where at low intensity, only some of the LEDs are lit and at high intensity, all of them are lit. If the difference between low and hi intensity isnt very significant, or the effect is muted by way of tallight lenses, it can be hard for the cars behind you to tell if youve appled your brakes or not. This same effect can also be a possibility when talking aobut side marker lights that also act as turn signals.

I dont have 1st hand experience with this, but I know poeple who do and felt uncomfortable enough to switch back to traditional bulbs.

if you want to ditch your daytime running lights, they should be on a separate fuse. just pull the fuse, and no more DTLs running off your alternator.

Unfortunately not all vehicles have a simple fuse to pull for DRLs. My Pontiac has "smart" logic that disables more than just the lights. And it beeps at you. Constantly. I'd disable it (as there has been found a workaround) but I enjoy not thinking about lighting when I get in it; the lights work. I replace a $5 bulb one a year or so from burning out, which is mostly because I have the lights relayed directly to the alternator, so the voltage drop is negligible-providing greater lighting at night (I work nights, so it's important to me). And my wife enjoys the extra visibility factor when we have ugly days. The car is silver/grey, it blends far to well with flat lighting.

But you're mostly right. DRL is a simple thing to disable, and even in my case, takes 15 minutes of reading a forum post while staring at the fuse box.

But daytime running lights are required by law in some countries...

HIDs use less power that would solve your headlight issue and provide a much brighter light!
LEDs are fairly cheap now( have my entire dash done in Blue LEDs(left the warning lights all stock so they really pop of they go off)...all the accessory lights are done in LEDs too
if nothing else they just look cooler and are customizable!
ebay you can find some killer deals on LEDs too!

"Where are DRLs required? Laws in Canada, Denmark, Finland, Hungary, Iceland, Norway, and Sweden require vehicles to operate with lights on during the daytime. There are two types of laws. Canada's requires vehicles to be equipped with DRLs. The other type of law in effect in Denmark, Finland, Hungary, Iceland, Norway, and Sweden requires motorists to turn on their headlights if their vehicles do not have automatic DRLs. This kind of law applies to drivers only, and vehicles do not have to be specially equipped. In 1972, Finland mandated daytime running lights in winter on rural roads and a decade later made DRLs mandatory year-round. Sweden's law took effect in 1977, Norway's in 1986, Iceland's in 1988, and Denmark's in 1990. Hungary has required drivers on rural roads to operate with vehicle lights on since 1993. Canada requires DRLs for vehicles made after December 1, 1989. No U.S. state mandates DRLs, although some require drivers to operate vehicles with lights on in bad weather." Questions & Answers: Daytime Running Lights



Almightybmw your Grand Prix is easy to disable the DRL its disconnect a the plug from a little heat sink that is in the panel you see when the drivers door is open. Check out Headlamp Control for more info on it and a pic of the part.

what is the current draw of DRL, especially considering they are at a lower intensity? I somehow doubt it would make more than a 1% difference in fuel mileage, especially compared to using other ecomodder techniques.

I think DRL's run at 90% of the power of the headlights, so ~45watts?

Found this from that link that Phantom posted:
I have popup lights so it is not just about alternator load, but Cd increases when lights are open.

In Estonia we also must use headlights all time. Is the DRL same thing as low beam?

I have replaced all interior and exterior lighting with LEDs, except turn signals (relay needs a specific bulb resistance to run) and headlights proper.

If all these bulbs were to run simultaneously, with no headlamp bulbs on, this would draw 330 watts. LEDs can do with 1:10 of this.

Also replaced 55 watt H3 foglight bulbs with motorcycle type 35 watt H3 bulbs. Since the fog lamps have dual lens, difference in light spread and reach is rather small.

The fuel savings are too small to count on an open road. But this is not the point. The gain is the decrease of the amp load on wires and relays. The electric system of modern VWs / Audis / Seats / Skodas is very tightly fit together, and, after some years in harsh temp differences from season to season, the wires cook and harden themselves.

If and only if the H7 / H1 headlamp bulbs could also be replaced with LEDs, the fuel saving becomes big enough to count.

in my country lights are required to be on unless you have DRL, so i've been interested about leds

They sell aftermarket halo lights. You could stick some inside you headlight lenses.

Or they have some strips you could mount anywhere.

In rural Finland, being noticed is important in my opinion.


Tykkimies Naskali.

There are LED DRL-kits sold that meet the legal requirement, RL is the code IIRC.

Here is my car with such a kit installed where the ((to me) useless) fog lights used to be:
http://ecomodder.com/forum/member-ja...re7595-drl.jpg

Only uses ~8 watts instead of the ~130 watts i needed before. (For Sweden, Finland etc. Biltema sells relatively cheap kits)

Update: Just searched, and it seems they don't sell them anymore.

Shortly after I got my car, I pulled the fuse to disable the DRLs. Didn’t notice any obvious mileage improvement, although I bet having those DRLs on was keeping the alternator charging all the time. I sort of recently figured out that my car has a smart alternator that trickle charges during no-load conditions and charges during load or deceleration. Honda switched from incandescent to LED tail lights for the 2006+ accords among other things. No difference noted in the EPA ratings, but they sure do look cool!

You would be hard pressed to justify LED taillights on a return on investment scale.

The problem I can see with those is getting pulled over for having your fog lights on (depending on local laws).

I used Phillips DRL8's previously cut into the bumper vents of a Mercedes van looked OEM and took ten years off the vans appearance.

I got a bunch of leds off of eBay for about $5-10 for 10 each!! I don't see much point in getting leds unless you plan on eliminating the alternator which would increase battery life significantly!!

So, I've thought of doing this as well. I already have about 90% of my interior lights switched over to LEDs and I plan to install LEDs for all of my exterior lights. This thread was started in 2009... Does anybody know if they have made LED headlights that are actually bright enough for headlights yet? If not, I plan to switch to HID projectors. Yes, expensive and won't do much (if anything for FE) but it's a safety thing for me. My housings just do not provide enough focused light even with good quality bulbs.

Also is there any way of changing to a smaller, more efficient alternator (I don't like the idea of not having one) or clutched one?

I found some headlight replacements on eBay for about $35 a pair that I'm going to test out in a week or two if your willing to wait and see how it goes??

Yes, they make LED headlights that are bright enough...they're just not the cheap cheap ones. Stovie's price is about right for a starting point. Look for the ones with the braided "ribbon" heatsinks at that price point. A user on another forum showed a regular bulb in one headlight vs said LED against a wall at a distance, and the LED was a bit (but noticeable) brighter.

Remember that's internet advice. YMMV. ;-)

Awesome, I can't wait to find out the results. Although I must warn you, eBay is not the best source for LEDs, in my experience. I changed all of my gauge cluster with eBay LEDs and they burned out in a few weeks. Replaced them with some quality ones from SuperBrightLEDs (more expensive) and they have been going strong for 2 years.My LED dome light from eBay lasted about 10 months and is now dead. Still need to replace that one.

I use LED tail lights for 2 reasons.
They are brighter.
As part of an overall vehicle power consumption reduction plan.

I just don't see a ROI for tail lights other than they are brighter which has a safety/bling benefit. I will probably change the tail lights on my RV over simply because the old stock ones are notoriously weak.

I've had LEDs that are now on their 4th vehicle. It's a bit of a pain to change back and forth each time, but the ROI is a long term game. I buy good ones (~$40) though.

They also light up the equivalent of 16' earlier than filament bulbs at 60mph. One rear ending avoided will change that ROI in a hurry.

You beat me to it. Good quality LEDs will outlive filament bulbs by a lot. They will pay for themselves in replacement bulbs eventually... It will just take a long time.

That's a very good point about the ROI for not getting rear ended. :thumbup:

Welcome

Tiny, tiny part. Nowadays, the Prius gets average gas mileage for a car in it's aerodynamic class (it just got there first). Consider this strategy: Acquire a set of complete Prius taillight assembies. Add a short boat tail to improve the Coralla's fineness ratio and incorporate the Prius taillights. First gen if you stay with a notchback, or later if you go to a Kamm-back.

For the headlights be wary of the beam pattern. Also, there exist HID projector headlights.

https://www.amazon.com/Nilight-Drivi...9TCN40ZK8Z0GD8

I used just one of these for my scooter
It's very nice to see with compared to stock

This is an old thread, but I can't find anything more relevant.
My question is about OLED taillights. I saw some blogs post articles about them being the best option for taillights because they are so awesome. But then, don't they need more power to work?
Like how does this work? Can OLEDs actually make any difference in mpg, or are they just for fancy designs? Maybe someone already had some experience with them

Typically LED lights require much less power than incandescent bulbs so they are more efficient. But tail lights do not consume much power, so it would take a few hundred years for you to see a return on your investment. LED lights are a fraction of a second faster, I am not sure how much of a real benefit this is.

Some prefer LED's because they are more robust and this is generally the case but I have seen some very bad LED designs that dont even last as long as an incanedescent bulb.

Large packs of Aliexpress LEDs are basically as cheap as Sylvania incandescent bulbs for replacing already burned out bulbs, but yea I wouldn't bother replacing them for energy savings because they're intermittently used. Headlights use much more power.

Consider any increase in visibility as added value.

Now I'm thinking about adding a separate RGB LED so I can have virual blue dots.

Tried led lights for my brakes. They consume too little power and it trips off my dash. Don’t feel like spending extra and setting up the capacity controller or whatever it’s called. So I put halogens back in. My headlights are another story