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I just finished this a couple days ago. Great mod. Connected the positive to unused tab from the horn relay then to a C/B. From C/B to light relay. Also use horn relay for ground wire. Better access if you remove the hood. Night driving is much improved with both brighter headlamps and gauges
I just finished this a couple days ago. Great mod. Connected the positive to unused tab from the horn relay then to a C/B. From C/B to light relay. Also use horn relay for ground wire. Better access if you remove the hood. Night driving is much improved with both brighter headlamps and gauges
Nicely done. Folks seem to concentrate on the increased current to the headlamp via relays but an equally big advantage is getting the load off your headlight switch. Its now just a low-amp trigger for the relays.
Mad Electric has a lengthy article on why the horn relay buss is the place to tap into for hi-amp accessories/mods if you want your dash gauge to read correctly and the charging circuit to work properly
Thank you for taking time for a very detailed response to my question. You are obviously trying to prevent me from "knowing wrong really well". You have done this many times and this is my first so I will listen.
Originally Posted by DUB
And that is entirely up to you. But you are asking...and many of us know wrong really well also....and wanted to convey the importance of KNOWING this value. That is all
OK I will measure the amps. My H5006 are rated approx. 3/3 amps ( hi/lo) and the H 5001 are rated 4 amps (hi). So on low beam I can expect 3 amps per side and 6 amps at the relay. On hi beam I can expect 7 amps per side (3 +4) and 14 at the relay.
If these BOSCH relays are in the interior...YES I WOULD...but out in the engine compartment...NO I WOULD NOT...which is why I mentioned the relays that I use that are water tight....and can carry the load. But do as you wish.
Agreed. But putting the relays in the interior requires running the headlight power leads to the front of the car and I do not want extra wiring along side the factory harness. I would also have to run harness up to horn relay as I want to tap the 12 v power on the line side of the firewall connector. Personal appearance issue vs better environment for the relays. Putting the relays on radiator support, although more hostile for the relays, will allow my fabricated harness to be in front of the radiator support and not as noticeable IMO. By the way I have bought Packard 56 male and female connectors so my harness will not require any splicing into existing factory harness, just plug in.
You can not 'take some of the load off'...when the load has to be there to make components work. You can do it another way that can make some components work better that originally designed. But the headlights are going to need what they need. But increasing the gauge size helps....and I am fairly confident of using 14 gauge is fine. AND YES...by installing these relays...if out in the engine compartment...you are actually reducing the amp load on the wires in your bulkhead/firewall connector that have the high/low beam wiring going through it.
Agreed. I did not explain it very well. You did. Taking 14 amps (assumed value till I measure ) off the horn relay for the headlights takes 14 amps off that 12 ga red wire that feeds power into the car thru the firewall connector and yes 14 less amps coming back thru the firewall connector for the headlights. My 46 year old harness could use the relief and I'll feel more comfortable when I turn the lights on. UB
My original question was will all this be for naught because I plan to use the factory 18 ga and 16 ga factory headlight extensions. Even if I do get some voltage drop I don't think it will be significant and I am better off taking some of the current load off that the headlight switch. Some are reporting brighter dash lights too.
Ok for alternator conversions, I recently put up a bunch of my helpful raw notes in a recent thread to help everyone with that. I even had pulley diameters to run things round and round, that spin the alternator!
Ok simpliest thing to do and no one here suggested it,, I know for sure because I actually read some other peoples posts for once, but mock up the relays and light to the existing looms just for testing and take some readings instead of just trusting someones specs or calculations. Put an amp meter or whatever reading you are thinking you want. There are wire gauge charts based on length of run that give amp loads. For a quick hookup of what you plan to run for a moment, it shouldn't hurt anything. But if you see smoke or something stop there immediately!
I also thought I gave a bunch of tips above. I probably have guys around the Country planning trips to the junk yards this weekend, guys buying soldering guns and heat shrink/heat guns, and throwing out yellow, blue, and red splices, lugs, etc.! all from one awesome post sharing! Smile thing here!
How is that! But you can call me out, because you come on and are helpful to people often. i see it!
Was that good enough?smile thing beer toast!
I DID NOT MEAN to make you feel like I was calling you out..OR that your advice/comments are not worthy...QUITE THE OPPOSITE...or making my comments seem like yours were not useful/helpful. If it came across that way.. I DID NOT intend for it to do that...and for that I SINCERELY apologize for any misunderstanding. Not meaning to seem like I am kissing @$$...just that I do not like it when I do not convey what I am trying to communicate correctly.
When I typed out what I recently posted...you posted what you did....I I HONESTLY felt what I wrote to the original poster of this post was 'kinda overkill'...but still kept it to possible help others who may wan to read it. So...my post after yours seemed to me to be pointless.....but I kept it any way....and AGREED with you...and KNOWING your are helpful is why I wrote that part....so hopefully all the 'stuff'' I wrote MAY help someone.
YES...I have a wire gauge chart...and I also know that in some cases...it does not come into effect. Sometimes going with much larger gauge wires is actually BETTER...due to is any voltage drop is occurring...even in the smallest amounts...it can effect the performance of some parts...such as externally mounted electric fuel pumps.
I agree with doing a pre-test set-up...because I have the tools to do just that also.....but I did not mention it due to the basic information that was being asked was not being obtained...so why add more to a situation than was needed. I am glad that you did mention it for 'others' who may read this. So many things to often consider when doing a change or upgrade....that are not totally obvious.
Dub
My original question was will all this be for naught because I plan to use the factory 18 ga and 16 ga factory headlight extensions. Even if I do get some voltage drop I don't think it will be significant and I am better off taking some of the current load off that the headlight switch. Some are reporting brighter dash lights too.
Randy
Randy,
I hope I am not coming across as arrogant...but when it comes to electrical issues ...I pay serious attention....because I have seen many that have burnt to the ground due to poor repair practices.
Not meaning to imply that is what will happen to you.
You more than likely will be fine....but as many of us know....when dealing with a blower motor...often times increasing the ground wire gauge size and or power wire will aid in the fan motor working better. I have not done any test on air flow before and after a repair of this nature...but I will the next time...and I know for a FACT.
That the aftermarket external electric fuel pump that is on a Corvette I am working on.... when I called them...wanted me to use a MINIMUM of a 12 gauge wire going to the fuel pump...and 10 gauge would be better. SO...I removed the 16 gauge wire and installed a new 10 gauge wire...even though the fuel pump draws under 20 amps. They are concerned in voltage drop and fuel pump performance due to this drop...and the larger gauge wire basically aids in stopping this.
I did mine "stealth" style in the unused voltage regulator and the relays are protected from the ravages of the engine bay. All connections are soldered for best current transfer.
???????? I was OK, I do need to fix that smiles function on my cheap laptop!
Originally Posted by DUB
I DID NOT MEAN to make you feel like I was calling you out..OR that your advice/comments are not worthy...QUITE THE OPPOSITE...or making my comments seem like yours were not useful/helpful. If it came across that way.. I DID NOT intend for it to do that...and for that I SINCERELY apologize for any misunderstanding. Not meaning to seem like I am kissing @$$...just that I do not like it when I do not convey what I am trying to communicate correctly.
When I typed out what I recently posted...you posted what you did....I I HONESTLY felt what I wrote to the original poster of this post was 'kinda overkill'...but still kept it to possible help others who may wan to read it. So...my post after yours seemed to me to be pointless.....but I kept it any way....and AGREED with you...and KNOWING your are helpful is why I wrote that part....so hopefully all the 'stuff'' I wrote MAY help someone.
YES...I have a wire gauge chart...and I also know that in some cases...it does not come into effect. Sometimes going with much larger gauge wires is actually BETTER...due to is any voltage drop is occurring...even in the smallest amounts...it can effect the performance of some parts...such as externally mounted electric fuel pumps.
I agree with doing a pre-test set-up...because I have the tools to do just that also.....but I did not mention it due to the basic information that was being asked was not being obtained...so why add more to a situation than was needed. I am glad that you did mention it for 'others' who may read this. So many things to often consider when doing a change or upgrade....that are not totally obvious.
DUB
DUB
You had the topic well covered. My stuff was just tips compared to your advice! I wasn't the slightest upset, and was trying to be funny, but that smiles function would help. I was fine all along! Everything was thru the whole thread cool! You do help alot of guys and are ver y thorough, my compliments!
I have seen plenty a car with new advanced wiggets wired in and load the system causing problem or they cause a situation where the battery with the wiggets on causes a continuous discharging state for the battery under some driving conditions. The alternator upgrades are smart if you are running high powered lamps, electronic ignition boxes, fans, stereo, cell phone charging, hair dryers, hot dog cooker, iron boards, and whatever else guys tend to install! Place one of those smile things here!
Last edited by TCracingCA; 11-22-2014 at 03:18 AM.
Came across this website researching relays, wire size etc. It is basically for car audio types but still relevant for us. At the end of the relay section there is a wire and fuse size calculator. Enjoy
Thought I would post the results of my headlight relay project and close this thread out. Thanks to all who responded with all the good advice.
I mounted the relays on a mounting pan
The relays are mounted on the radiator support in front of the horn relay using existing mounting bolts. The coil grounds are terminated at the horn relay ground
I fused each relay to give me a little more reliability in case of electrical failure. Horn relay buss getting a little crowded
12.4 volts on passenger side high beam. Before relays 11.4 or 8% increase.
I used 14 ga wire for the new harness and plugged into existing headlamp extensions. On low beams I got 5.1 amps and on high beams I got 11.7 amps at the fuse block. On low beam with engine idle I got 13.3 volts ( 12.65 before) and on High beam I got 12.4 volts (11.4 before) or about 8% increase for high beams. That translates to about a 20% increase in lumen output according to chart in Daniel Stern Lighting article.
A little "busy" around the horn relay. I may add a terminal block and power the relays from there and hide the fuseholders but for now all is good. Thanks again to all who offered suggestions.
11-20-2014, 11:46 PM
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UB
