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The ultimate headlight upgrade H4 (not LED or HID)

Discussion in '2nd Gen. Tacomas (2005-2015)' started by crashnburn80, Oct 27, 2015.

  1. Nov 16, 2015 at 2:17 PM
    #101
    maunman

    maunman Member

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    Why would I even test the low beams?

    My decision to keep the factory wiring for now is based on the assumption of 20-gauge GXL wiring, which I haven't confirmed. However, a 108 deg F plug implies the wires' insulation is far cooler so even GPT insulation would hold up forever.

    The only way to melt the fuses is to let my battery voltage drop below ~11.5V with the high beams on, based only on calculated impedances for now.

    Haven't measured current or potential differences at the fuse and bulb terminals yet, but I have seen 130W H4 bulbs used in ~22/24-gauge wiring with current running through the factory light switch on other Toyota trucks (not manufactured in Japan or NA, so under-spec'd by Toyota Motor Corp's standards,) and the bulbs barely glowed at all. These things
    Between that and the wiring temps, that's the only real evidence that I need to know everything is adequate.

    After measurements and a wire size confirmation, I may still decide to beef up the wire, but so far I have no good reason to.
     
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  2. Nov 16, 2015 at 2:25 PM
    #102
    Backt

    Backt Well-Known Member

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    I'm technically challenged with wiring. I unplugged my plug to the light. The horizontal plug has 12+volts with the lights on. The left vertical (looking from the back) has nothing and the right has .1. I'm guessing I need the conventional harness?
     
  3. Nov 16, 2015 at 2:33 PM
    #103
    crashnburn80

    crashnburn80 [OP] Vehicle Design Engineer

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    That is correct. That means you are conventionally switched.

    How do you figure? 130w/10amp (fuse) = 13v. Regardless I would suggest upgrading the harness. If you don't, report back and let us know how things have held up over time.
     
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  4. Nov 16, 2015 at 3:19 PM
    #104
    odomandr

    odomandr Well-Known Member

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    Icon, AllPro, Total Chaos, ARB, BAMF, Relentless, SCS, Cooper, Leer,
    Headlight recall ends this month I b elieve
     
  5. Nov 16, 2015 at 3:24 PM
    #105
    nd4spdbh

    nd4spdbh Well-Known Member

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    yeah.... i wouldnt be running a 130w bulb on the stock harness.... i looked at the stock harness when i was adjusting my headlights this weekend..... its pretty wimpy... OP has the right idea with the fatty external harness, i wouldnt go above the 85w mark with the stock harness even if the fuses are rated for 10amps.
     
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  6. Nov 16, 2015 at 6:03 PM
    #106
    maunman

    maunman Member

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    MINI fuses carry 110% of their rated current for 136,000 seconds by design specification (indefinitely). I used the nominal impedance to figure out how many volts across the high beam filament it would take to draw 11 amps. However, this was just a back of the envelope calculation using nominal values, so it's still just an educated guess that gets a little closer than assuming a voltage first. Impedance is more of a constant, and only varies with manufacturing tolerances.

    The last time I rewired an H4-based headlamp was for my motorcycle. I did the same thing with it, first just trying a 100/80. It burned brighter than the 60/55 bulb, but I could tell it wasn't burning at its brightest so in went some relays and 14-gauge wire.

    In this case, since it's already relayed from the battery, through dedicated fuses for each filament, right from the fuse box to the bulbs, the result is very different. It may be pushing the limits by calculation, but from an engineering perspective and no opinions about what a wire looks like, it carries the current needed without heating up. And I like pushing the limits of the wire to use it as a series resistance to prolong my bulb life while lighting up the road extremely well compared to the 9003 bulbs. I've been doing this for fifteen years and have seen it all when it comes to overwattage bulbs. I'm very impressed with what Toyota has come up with on this vehicle.

    But let me be clear about this:Bypassing is better...even using a 60/55-watt bulb, you'll still see a difference in brightness because P=V^2/R...voltage has a squared relationship to power. So what crashnburn has done here is absolutely the ultimate headlamp upgrade. It's better from a system design perspective. My bulbs really should have at least a 15A fuse for each high beam, but I'm not about to change sizes without measuring the wire size (not guessing). He's convincing me to rethink any thoughts I had about keeping this setup as a long term solution even if my fuses haven't melted yet. (I was sure to run the high beams with alternator for more than 1000 seconds during my tests, which is where the MINI fuse TCC graph stops on the time scale.)

    I will definitely post something if a fuse melts or anything else seems suspicious or goes wrong. When I find the time, I am going to measure current and potential differences across the fuse terminals...which tells a lot about how close it is to its melting point for real with no guessing or estimates, and to see just how much current is running to each high beam. If anyone else is reading this for ideas and you think I'm crazy, hold off 'till I get the full story to report.
     
    Last edited: Nov 17, 2015
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  7. Nov 17, 2015 at 4:23 AM
    #107
    maunman

    maunman Member

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    Sounds like you do. If your negative probe was on the battery negative post or any other ground and you got nothing on the left vertical plug, which is the "common", it shows that the common is grounded by vehicle design. I'm guessing you had your low beams on at the time since the horizontal pin had 12+V. (The .1V you picked up on the high beam pin would have been because of other shared connections between the high and low beam circuits throughout the system.)
     
    SouthernWild likes this.
  8. Nov 17, 2015 at 10:02 AM
    #108
    Dr. Jekyll

    Dr. Jekyll Well-Known Member

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    crashnburn80[OP] likes this.
  9. Nov 17, 2015 at 1:35 PM
    #109
    maunman

    maunman Member

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    8.9A and 13.25V across the high beam terminals of the 130/100W bulb with the engine at 2500RPM and the battery voltage at 14.25 V. (My Fluke 88 is generally accurate but it hasn't been calibrated in forever.) Measuring from negative terminal of battery, 13.75V from terminal to high beam terminal. All the series resistance in the high beam circuit is preventing the nominal power dissipation to be realized.

    So all the unfounded opinions about melting or inadequate wires, on this thread and the many others, are not holding up. HOWEVER, a wiring harness will give significantly less voltage drop and ANY bulbs will burn brighter than they will with the stock wiring. If you'd like over wattage bulbs, a wiring harness is good engineering design, regardless if it's physically possible to get away with even a 130W high beam.

    I didn't take time to measure the low beam current or voltage, because this is about giving us all a solid foundation of just how capable the stock wiring is. Again, it's better to bypass it. And always go with good quality relays and bulbs from trusted sources. Well done on the work and post crashnburn!
     
  10. Nov 17, 2015 at 1:41 PM
    #110
    klavender1

    klavender1 Well-Known Member

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    I've got the Daniel Stern kit built but haven't installed it yet. And honestly I never measured the stock voltage to see what the drop was. Has anyone measure the voltage drop on our trucks to see how much we're actually losing at the bulb? Assuming everything is stock?
     
  11. Nov 17, 2015 at 1:45 PM
    #111
    Dr. Jekyll

    Dr. Jekyll Well-Known Member

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    Spot on :thumbsup:
     
  12. Nov 17, 2015 at 1:53 PM
    #112
    MustDrive

    MustDrive Well-Known Member

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    Dave
    Minnesota
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    Nothing major planned, this is my daily driver. - replaced stock tires with Cooper AT3s - added Husky WeatherBeater floor mats - installed Access Original bed cover - installed Gentex 453 mirror and the included external temp sensor, also has Homelink and auto-dim - installed ImMrYo mirror bracket - hose clamp mod and washer mod to secure tailgate, with a GateKeeper lock installed over the hose clamp - replaced stock reverse lights with Philips Halogen 30w from Home Depot GY6.35 base
    After reading this thread, I decided to upgrade the harness and headlight bulbs in my 2014 Tacoma.

    In short, so far I have installed a new 12-gauge wiring harness giving me an extra .4 Volts at the bulbs - voltage drop reduced from .65 volts to .25 volts.

    Details:

    I am doing it in stages, taking voltage readings and pictures of the headlight output at each stage - on the same road, same viewpoint. I am using the same manually-controlled camera exposure settings for all the pictures.

    I measured the initial voltage drop of the factory headlight wires in 2 ways, and got 0.65 Volts of drop using either method:
    1) the method described by the Daniel Stern website - a bit complex.
    2) actual voltage at the light, vs. actual voltage at the battery. This is done with the engine idling, headlights on, and all bulbs connected. I removed the passenger side bulb from the headlight, attached it back on the wiring connector but leaving a bit of the metal prongs accessible to my multimeter. This headlight voltage is measured on the passenger side bulb since it has the most drop. I moved the meter back and forth between the battery terminals and headlight wiring prongs several times, with engine idling and bulbs on the entire time.

    Today, I installed the "Premium-Plus" 12-AWG wiring harness with ceramic bulb sockets from Headlight Services, the one for conventionally switched vehicles with two H4 bulbs:

    http://www.headlightservices.com/Wiring.html

    I now have only 0.25 Volts of drop at the passenger bulb, measured the same method as in 2) above. I gained 0.4 Volts at the bulb. I had 14.05 volts at the battery terminals, and 13.80 volts at the passenger headlight prongs, with the bulb installed and headlights on.

    I took pictures of the output of the stock bulbs with the new wiring harness, then after installing my new Osram Rallye 70/65 bulbs. The light output increased at each stage. These pictures are on this thread.

    So, just doing the wiring harness upgrade with no other change will improve light output.

    Dave
     
    Last edited: Nov 30, 2015
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  13. Nov 17, 2015 at 2:11 PM
    #113
    crashnburn80

    crashnburn80 [OP] Vehicle Design Engineer

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  14. Nov 17, 2015 at 2:33 PM
    #114
    bigd9247

    bigd9247 Well-Known Member

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    I've been running an aftermarket wiring harness in my 2012 Tacoma since the day I bought it. I've been running 100/55w bulbs for a couple years and recently changed to 130/90w bulbs. So far no issues with either bulb setup. I can't remember the brand of my harness since I've had it for like 6 years and just keep re-using it whenever I buy a new truck.
     
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  15. Nov 18, 2015 at 4:08 PM
    #115
    crashnburn80

    crashnburn80 [OP] Vehicle Design Engineer

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    Had a major storm yesterday that knocked out power to most the city and took care of all those pesky street lights. I figured I'd use the opportunity to grab a couple light pics. Unfortunately the neighborhood doesn't really have any good straight level streets without going on main roads with plenty of traffic, so in both pics the road slopes away from the from the lights causing them to artificially cut off early. But at least it gives the lights some context. Probably would have been better if I grabbed my high quality camera rather than using a cell phone. I'll get around to that one of these days.

    light_1.jpg

    light_2.jpg

    Edit: I should mention I have the OEM fogs on, with stock bulbs. I didn't think to turn them off before taking the pictures.
     
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  16. Nov 20, 2015 at 12:02 PM
    #116
    Backt

    Backt Well-Known Member

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    I received my package this morning and plan to install it Monday morning. The male connector on the harness connects to the existing female connector nearest the battery. Do you tape up the stock connector on the other side or is there a cap you buy to prevent water from getting in it?
     
  17. Nov 20, 2015 at 12:43 PM
    #117
    danurse69

    danurse69 Active Member

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    Osram Rallye 70/65W headlights/Osram Nightbreaker fogs
    I use the Osram rallye(70/65W) off-roads in the headlights, and Osram Nightbreakers in the fogs on stock harnesses... definite improvment over the stock bulbs.
     
  18. Nov 20, 2015 at 12:51 PM
    #118
    crashnburn80

    crashnburn80 [OP] Vehicle Design Engineer

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    I did not tape it or cap it. You could tape it up with some electrical tape. There is plenty of dialectical grease in there to prevent any corrosion issues, at least on my 2015. It should be reasonably protected in the corner of the engine bay from road spray. I've run this setup for years on other trucks and had no corrosion problems when uninstalling it to return the truck to stock to sell.
     
  19. Nov 20, 2015 at 5:11 PM
    #119
    Dr. Jekyll

    Dr. Jekyll Well-Known Member

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    If I had a nickel for each drop of excess grease I'd have paid off my truck by now...
     
  20. Nov 22, 2015 at 4:25 PM
    #120
    EGoldie

    EGoldie Some Miles Under My Belt

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    Hey guys. Where is the female connector located to plug in the male trigger relay on the harness? Am I pulling a relay in the fuse box or what?
     

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