LED lights for better fuel economy....

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
HI All,

I read over on the ecomodder site that removing an alternator and running off a battery can net about 10% better fuel mileage.

I cannot be that extreme since I drive long distance and cant afford to run out of juice at a bad time (is there ever a good time to run out juice?)

I was however hoping to convert ALL my lighting to LEDs in the hope that the reduced energy usage would net me more MPG's.

Has anybody here done that already?...If so what were your results mileage wise?

I know people don't like LED Headlight replacement bulbs (more light scatter and maybe even not as long a range of lighting but range would be a moot point for me since I will be running Rigid Industries LED aux lights (I got the D2 Dually driving beam set, SAE Fog light set, Spotlight set AND Hyper spot set .....I'm gonna have serious lighting power if / when needed)....Ive had them for awhile but have not had time install them just yet..

I was pondering the best way to bring the wires inside the passenger compartment to install the switches....Any ideas?....

Its crowded under there unlike my pickups which were easy to snake wires into the passenger compartment....I'll have to fab up some mounts to get the lights to sit i the grille area....I'll post pics when I finish....hoping to at least mount the lights this weekend....wiring may be another story unless I opt for the simple splice into the high beams and have them run that way....I'd prefer having different lighting options so switching will be necessary ).

I did think of going HID replacements BUT LEDs draw less juice and maybe will increase mileage more .....and yes the light scatter may actually help illuminate the sides and those pesky deer (on coming traffic please put on your sunglasses ;-) well, I hope its not that bad....maybe just squint a little ha (just kidding in case the man is reading this ;-) )

Thanks in advance for any and all help.
Andrew
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
Honestly don't think you'll notice a thing.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
It isn't going to make enough of a difference to notice. Changing *everything* over to LED will only save you a couple hundred watts, which at most (and this is being very generous) is going to be a 1 HP draw on the alternator. The money you save in fuel will probably never offset the cost of purchasing said LED bulbs.

Now, if you want to talk about lighting upgrades for the sake of improved lighting and reliability, that's an entirely different story. :)
 

JohnnyCanuck.Comox

Well-known member
Joined
Dec 1, 2016
Location
Comox B.C. Vancouver Island
TDI
2004 Golf GLS
I installed truck-lite complete led headlight units which are DOT approved; these were for my '93 toyota 4x4. My oem headlights were drawing just over 5 volts, and the LED units were just under 2 volts on low beam and just under 3 volts on hi beam. I also changed out every bulb to LEDS and I was surprised that the bulbs didn't make that much of a difference in voltage over oem. Not worth the cost - at least on my truck - imo although I did like the white colour better and they were brighter.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
I installed truck-lite complete led headlight units which are DOT approved; these were for my '93 toyota 4x4. My oem headlights were drawing just over 5 volts, and the LED units were just under 2 volts on low beam and just under 3 volts on hi beam. I also changed out every bulb to LEDS and I was surprised that the bulbs didn't make that much of a difference in voltage over oem. Not worth the cost - at least on my truck - imo although I did like the white colour better and they were brighter.
What? How does a 12 volt car headlight only draw 5 volts (or two volts) when hooked to a 12 volt electrical system? Do you mean amps?
 

belome

Top Post Dawg
Joined
Apr 8, 2010
Location
Mid MI
TDI
2002 Jetta GLS TDI 5-speed
Man, I need to stay out of this sub-forum...

Let's spend $500 to save a buck.
 

SilverGhost

Veteran Member
Joined
Mar 25, 2005
Location
Back in So Flo - St Lucie
TDI
'05 Golf - totaled :(, wife's '13 Beetle - buy back, TDIless
This is like changing all of the bulbs in your house from incandescent to LED, but leaving the 20 year old furnace, 10 year old water heater and fridge installed.

I was reading about energy usage of household appliances and current refrigerators use less power than the current cable box from Comcast or DirecTV.

BMW did something with their alternators in the last few years. They program them to stop charging on acceleration and switch to heavy charging on deceleration. I believe they also limit charging during steady driving. It would be an interesting experiment if you could modify the regulator and rig up some sort of control to allow you to do this yourself.

On that note you also have a power steering compressor that is constantly running. Maybe remove it and rig up an electrical hydraulic pump. Build pressure to an accumulator and only run the pump for short bursts. Older Mini used a setup like this.

Just so you know - ROI is going to suck! This is all just for your fun.

Jason
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
And changing from incandescent to LED also increase's your heating bill. :eek:
 

JohnnyCanuck.Comox

Well-known member
Joined
Dec 1, 2016
Location
Comox B.C. Vancouver Island
TDI
2004 Golf GLS
What? How does a 12 volt car headlight only draw 5 volts (or two volts) when hooked to a 12 volt electrical system? Do you mean amps?
yes, amps, and I meant 15 not 5. It's not my fault, it was the inauguration, I was watching and typing! here's the lights I had in my toyota: http://www.truck-lite.com/webapp/wcs/stores/servlet/ProductDisplay?urlRequestType=Base&catalogId=10002&categoryId=13091&productId=48711&errorViewName=ProductDisplayErrorView&urlLangId=-1&langId=-1&top_category=15554&parent_category_rn=13089&storeId=10001

and how they looked in my truck:
 

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
A watt saved is a watt saved, no denying that. But the magnitude of the savings with all-LED lights will produce no noticeable returns when the fuel receipts are tallied up, no matter the expense put upfront. Just saying there are other, lower hanging fruit elsewhere, eg in removing unnecessary weight in the car, driving more slowly, combining trips/errands, anticipating slowdowns and stops in traffic ahead and using the brakes less, reduce unnecessary idling, properly inflated LRR tires, low-viscosity lubricants in the engine/gearbox, etc.

Edit: to add to that most if not all LED lights that are sold as "CANBUS error free" have load resistors and telltale heatsinks so that they mimic the resistance of normal bulbs, so the power draw, given by P = V*I =V^2/R is pretty much exactly the same. A total fail mod if you thought you'd be saving some electrical power...
 
Last edited:

Aknovaman

Well-known member
Joined
Sep 26, 2016
Location
Tecumseh
TDI
2001 golf tdi
On a side note, i replaced 48, 60 watt incandescent conventional light bulbs in my house at a cost of approximately $120. My electric bill dropped by 40%. Return on investment or should i say, they paid for themselves in 2 months. Plus i have not replaced a light bulb in over a year since the changeout.
 

fruitcakesa

Top Post Dawg
Joined
Feb 18, 2007
Location
Vermont
TDI
04 jetta 5 spd wagon
On a side note, i replaced 48, 60 watt incandescent conventional light bulbs in my house at a cost of approximately $120. My electric bill dropped by 40%. Return on investment or should i say, they paid for themselves in 2 months. Plus i have not replaced a light bulb in over a year since the changeout.
Great example of small things making a big difference.
Folks don't realize how much lighting they leave on.
It is taken for granted and the cost is probably thought to be minimal.
 

ZippyNH

Veteran Member
Joined
Apr 22, 2015
Location
Southern NH
TDI
2015 JETTA TDI SE
A watt saved is a watt saved, no denying that. But the magnitude of the savings with all-LED lights will produce no noticeable returns when the fuel receipts are tallied up, no matter the expense put upfront. Just saying there are other, lower hanging fruit elsewhere, eg in removing unnecessary weight in the car, driving more slowly, combining trips/errands, anticipating slowdowns and stops in traffic ahead and using the brakes less, reduce unnecessary idling, properly inflated LRR tires, low-viscosity lubricants in the engine/gearbox, etc.

Edit: to add to that most if not all LED lights that are sold as "CANBUS error free" have load resistors and telltale heatsinks so that they mimic the resistance of normal bulbs, so the power draw, given by P = V*I =V^2/R is pretty much exactly the same. A total fail mod if you thought you'd be saving some electrical power...
+1

Also another note...
Be 100% sure that your ur TAIL LIGHTS turn on with your newly wired headlights...(sounds like you are planning on using an alternative switching and wiring system you make)...
I have seen many getto wiring jobs where they wire the headlights but fail to give you tail lights....Can be very dangerous.
I honestly doubt you will save more than a few fractions of a % ...Never enough to pay for the mod....Too put it into perspective, a 3000 watt generator uses about 6 HP at full blast ....compare that to you alternator, a FRACTION OF THE SIZE, AND THEN USUALLY RUNNING A FAIRLY LOW % its max output...As stated, about 1 HP...
You would get more gain for lower costs doing basic things, like hubcaps, anteana removal, mirror removal, roof rack removals, and even the FOG/DRIVING LIGHT REMOVALS, and smoothing the bumper....
 

Lug_Nut

TDIClub Enthusiast, Pre-Forum Veteran Member
Joined
Jun 20, 1998
Location
Sterling, Massachusetts. USA
TDI
idi: 1988 Bolens DGT1700H, the other oil burner: 1967 Saab Sonett II two stroke
Alternator draw (load on the engine) is variable

The alternator uses less engine power as the battery voltage increases. The biggest load on the alternator is in the moments after engine starting when the battery has expended power to run the glow plugs and spin the starter. As the alternator replaces that expended battery capacity the alternator load dimishes to only that needed to maintain the battery capacity against other loads, like the lights (ECU, radio, wipers, whatever else is switched on).
What that means is that within a few minutes of starting the engine, the battery has been topped off and the alternator is almost, (not quite), spinning with no load.
That said, the 10% improvement isn't out of the realm of possibility. A pair of 55W headlights consumes 110 watts or (about) 1/7 of a HP (746 watts).
If the low air drag car only needs 7 HP to drive at a steady, flat road, no headwind, speed, the headlights on are using 10% more.

But, for a long trip as you mention, I'd rather have a charged starter battery for the return trip particularly when I can save that 1/7 HP other (FREE) ways.

I was on Ecomodder for a while, but I realized they tend more to "modder" without considering the "Eco".
If you want to spend money and personalize your ride to be different, go right ahead.
 

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
A watt saved is a watt saved, no denying that. But the magnitude of the savings with all-LED lights will produce no noticeable returns when the fuel receipts are tallied up, no matter the expense put upfront. Just saying there are other, lower hanging fruit elsewhere, eg in removing unnecessary weight in the car, driving more slowly, combining trips/errands, anticipating slowdowns and stops in traffic ahead and using the brakes less, reduce unnecessary idling, properly inflated LRR tires, low-viscosity lubricants in the engine/gearbox, etc.

Edit: to add to that most if not all LED lights that are sold as "CANBUS error free" have load resistors and telltale heatsinks so that they mimic the resistance of normal bulbs, so the power draw, given by P = V*I =V^2/R is pretty much exactly the same. A total fail mod if you thought you'd be saving some electrical power...
HI,

Good points about the CANBUS / resister thoughts....(i'm already doing most of the other "regular" stuff so I was having to look into other areas for potential savings (yes, not necessarily cost effective sometimes but I suppose some of it is for fun and bragging rights than overall ROI unless smiles per mile counts....HA).

Anyways, I had spoken with somebody over at Super Bright Leds and they told me that the CANBUS lights add about 50% of the resistance back to keep error lights from happening and also to help with hyper flashing therefore effectively only saving about 50% in energy savings since about 50% is added back in to keep computers etc..

I think there are mods that can be done to allow the LEDS to be operated without needing the added resistance (thus saving energy needs) ....There was also a mod to the flasher that eliminates hyper flashing (fast flashing) of the signal lights etc...I'm researching into this now.

Its a shame that regular LEDS are not more truly plug and play into newer vehicles..
 
Last edited:

TDIMeister

Phd of TDIClub Enthusiast, Moderator at Large
Joined
May 1, 1999
Location
Canada
TDI
TDI
I'm 100% for LEDs that don't employ any load resistors and hyper flashing behaviour. My car has 35W HIDs for fog/DRLs, 35W HID for low beams and LEDs for the City lights (Euro spec only) and LEDs throughout the interior, back up lights and rear fog. Turn signals and brake lights remain incandescent because of the hyper-flashing and bulb-out warning on the cluster. As technology matures there will be solutions to these issues without the price premium of having these features as a niche.
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
On a side note, i replaced 48, 60 watt incandescent conventional light bulbs in my house at a cost of approximately $120. My electric bill dropped by 40%. Return on investment or should i say, they paid for themselves in 2 months. Plus i have not replaced a light bulb in over a year since the changeout.
40%, sorry, I call BS.
 

Aknovaman

Well-known member
Joined
Sep 26, 2016
Location
Tecumseh
TDI
2001 golf tdi
It's unfortunate that you have that viewpoint and call my statement as BS. If I could figure out how to scan my power bill and attach it would that make you a believer? Likely not cause some would say that the summer we ran the AC less and in the winter was warmer so the furnace ran less and that was the cause of my power bills dropping. I am comparing the direct KW power use and excluding all the taxes and fees. We have gas heat live in Kansas in a 3400 square foot well insulated house with 3 teenagers and someone is always home. Yes it is about 40 percent less. For someone who lives in very cold climate whose furnace fan runs a bunch in cold weather, the savings would not be as substantial. I have zero regrets after changing to all led in and out of the house.

I am just happy now to have my first Tdi alh that gets 49.3mpg driving country roads back and forth to work instead of the 16.7 I used to get with my other car.

Good day.
 
Last edited:

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
Why is it unfortunate? You'd be the first one that cut their bill by 40% changing to LED's. I've done it, my friends have done it and the bill didn't change one bit, or if it did, not enough to notice. 40% is cutting your bill in half, the only way I can see it being done is if you left every light on in the house 24 hours a day.

Either way, glad it worked out for you. :cool:
 

sandmansans

Veteran Member
Joined
Nov 3, 2013
Location
NJ/PA
TDI
2014 Jetta
It's unfortunate that you have that viewpoint and call my statement as BS. If I could figure out how to scan my power bill and attach it would that make you a believer? Likely not cause some would say that the summer we ran the AC less and in the winter was warmer so the furnace ran less and that was the cause of my power bills dropping. I am comparing the direct KW power use and excluding all the taxes and fees. We have gas heat live in Kansas in a 3400 square foot well insulated house with 3 teenagers and someone is always home. Yes it is about 40 percent less. For someone who lives in very cold climate whose furnace fan runs a bunch in cold weather, the savings would not be as substantial. I have zero regrets after changing to all led in and out of the house.

I am just happy now to have my first Tdi alh that gets 49.3mpg driving country roads back and forth to work instead of the 16.7 I used to get with my other car.

Good day.
I believe you. In the home setting that's not untealistic or far fetched. Especially if switching from old incandescent 100w bulbs. You swap out 20 of those puppies for some leds it does add up drastically.
Let's do the math:
20 incandescent bulbs at 100 watts
= 2000 watts
Converted to led usually a 100 w equivalent bulb is around 15 w
20x15w= 300 w
That's an 85% difference in power use
(If my math is correct)

So his 40% is not that far off now is it!


Sent from my SM-N910V using Tapatalk
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
Why is it unfortunate? You'd be the first one that cut their bill by 40% changing to LED's. I've done it, my friends have done it and the bill didn't change one bit, or if it did, not enough to notice. 40% is cutting your bill in half, the only way I can see it being done is if you left every light on in the house 24 hours a day.
Either way, glad it worked out for you. :cool:
For someone with all-gas appliances (hot water, oven, stove, dryer, heat), a 40% reduction in the electricity bill from switching to more efficient lighting is pretty realistic.
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
For someone with all-gas appliances (hot water, oven, stove, dryer, heat), a 40% reduction in the electricity bill from switching to more efficient lighting is pretty realistic.
In that case, I stand corrrected. His electric bill can't be that big if he's only using it for lights.
 

VeeDubTDI

Wanderluster, Traveler, TDIClub Enthusiast
Joined
Jul 2, 2000
Location
Springfield, VA
TDI
‘18 Tesla Model 3D+, ‘14 Cadillac ELR, ‘13 Fiat 500e
In that case, I stand corrrected. His electric bill can't be that big if he's only using it for lights.
Do you just enjoy arguing with people, or ...? I agree that his payback number of two months doesn't make a whole lot of sense, but I also don't know what his electric rate is (not that I care).

The bottom line is that swapping conventional lamps for LEDs in a car will never pay off in fuel savings. If a person bought good quality ones, they might last longer than conventional lamps, but that's about it.
 

turbovan+tdi

Top Post Dawg
Joined
Mar 23, 2014
Location
Abbotsford, BC.
TDI
2003 TDI 2.0L ALH, auto, silver wagon, lowered, Colt stage 2 cam, ported head,205 injectors, 1756 turbo, Malone 2.0, 3" exhaust, 18" BBS RC GLI rims. 2004 blue GSW TDI, 5 speed, lowered, GLI BBS wheels painted black, Malone stage 2, Aerotur
Do you just enjoy arguing with people, or ...? I agree that his payback number of two months doesn't make a whole lot of sense, but I also don't know what his electric rate is (not that I care).

The bottom line is that swapping conventional lamps for LEDs in a car will never pay off in fuel savings. If a person bought good quality ones, they might last longer than conventional lamps, but that's about it.
Arguing? I guess stating a fact that you and him said that he is only using electric for lights is arguing, so that means his consumption will be lower? Got it. :rolleyes:
 

coalminer16

Top Post Dawg
Joined
Dec 11, 2008
Location
Central Wisconsin
TDI
Golf 2004
120 for lights and a two month payback with 40% saved would be a 120 bill going to around 70 without getting the calculator out. Not hard to believe. One friend who lives alone has a $50 electronic bill as he also has oil funance, ect. I have between 105 and 152 with not other expenses. But I never left extra lights on.

You may get better benifit from electronic pumps for things like the power steering since it isn't needed to steer all the time and you are moving mass and oil all the time vs changing the lights. But if they don't burn out then it is time saved.

Sent from my SM-G900V using Tapatalk
 

jdulle

Veteran Member
Joined
Feb 4, 2017
Location
Ithaca, NY
TDI
96 B4, 97 B4
I have noticed that with my honda insight I lose 4-7mpg with the headlights on. It wouldn't be nearly that much with a TDI, because the insight is much lighter with a smaller engine. Also the insight charges the 12 volt system with a dc to dc converter from the hybrid battery. In the summer it goes from 77mpg to roughly 70-73 with the headlights on. I haven't done any official tests, and also, it is usually colder when the headlights are on...but it is noticeable on the fuel economy display right after you turn the lights on. If you can get the bulbs for a few dollars, and put them in places that stay on all of the time like the license plate light, they might pay for themselves over a number of years if you log lots of miles with the headlights on. You would get a much quicker return with a partial grill block to keep engine warmer and improve aerodynamics.
 

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
I have noticed that with my honda insight I lose 4-7mpg with the headlights on. It wouldn't be nearly that much with a TDI, because the insight is much lighter with a smaller engine. Also the insight charges the 12 volt system with a dc to dc converter from the hybrid battery. In the summer it goes from 77mpg to roughly 70-73 with the headlights on. I haven't done any official tests, and also, it is usually colder when the headlights are on...but it is noticeable on the fuel economy display right after you turn the lights on. If you can get the bulbs for a few dollars, and put them in places that stay on all of the time like the license plate light, they might pay for themselves over a number of years if you log lots of miles with the headlights on. You would get a much quicker return with a partial grill block to keep engine warmer and improve aerodynamics.
WOW 4 to 7 MPG loss.....If you have DRL I would disable them if lights eat up that many MPGs.

My TDI has DRL........I wonder how many MPGs could be gained by disabling them?...I mainly run at night tho (long distance deliveries) so for me more important to save wattage rather than disabling lights but I guess every little bit helps.

I plan on the grille blocks but I have to get my aux lights installed first then block around them.....I have to hook up the scan gauge to make sure temps don't get too high with the blocking.

(FWIW I did pick up 4 lightweight VW Avus wheels yesterday in the hopes that the weight reduction will boost MPGs.......I plan on aero covers too (I did the pizza pan mod on the current steelies).

Andrew
 
Last edited:

compu_85

Gadget Guy
Joined
Sep 29, 2003
Location
La Conner, WA
TDI
... None :S
Let's do some maths here... Say all the lights on the car use 250 watts (60x2 for headlights, 10x10 for all the small running lights, and rounding up). That's 20 amps, or 0.34 hp. Assume the alternator is only 50% efficient, and we're at 0.68 hp. Perhaps enough to use a touch of fuel, but I doubt you'd see any difference at the pump.

From some articles I just found the power steering pump takes 1 or 2 hp simply circulating fluid around.

-J
 
Top