High-Beam Triggered Relay Behavior w/PWM CANBUS System?

[lysol]

I have read numerous online threads of people complaining about relays wired into the high-beam wires in the 2012+ JK Wranglers. From what I understand, the PWM pulses the electrical current to things in the vehicle instead of allowing direct/full current to flow. Does the chatter come from PWM flowing through the #86 and #85 terminals on a standard relay causing the electromagnet in the relay to "chatter"?

I am planning on wiring (3) micro relays actuated by the high-beam wire in my Jeep. These micro relays will act as a gate between the (3) auxiliary light relays and the (3) in-cab switches. This way, when switching on the lights in the cab, the switch signal will be stopped at the micro relays which won't close until the high beam is on.

Has anyone successfully ran relays off the high beam wire?

 

[kojackJKU]

MIne works fine. I have had it in two different PWM vehicles, my 2010 Patriot FDII and my 2011 JK unlimited. Both triggered fine. NO chatter, etc. I have my HID hellas hooked up to a switch in cab, and the high beam trigger. I turn them off and just use High beams when I want or swtich the lights on and use my high beam to trigger the HIDS. That way On the highways in the night I can just turn everything down with one flick.

 

[Hilldweller]

unless you can find a relay that works at a nominal 4v-15v, it will eventually get destroyed. I've mapped the duty cycle of the highbeam circuit on a o-scope and it goes from 4.6v to 12.6v. The 4.6 is miniscule but it matters.
I've obviated that with capacitors.
rallylights.com could build you a tap with everything wired it; they do great work.

 

[kojackJKU]

Bill Mine has been going strong since 2011. Does it take A LONG TIME for that to happen?

 

[onetraveller]

I have a rallylights.com harness and I don't believe it has any capacitors built into it. It's worked fine for the past 2 1/2 years. Only problems I've had with the rallylights H4 upgrade kit are going through a set of bulbs about every 6 months, and rocks cracking or chipping the glass Hella housings.

Mike

 

[Hilldweller]

I have a rallylights.com harness and I don't believe it has any capacitors built into it. It's worked fine for the past 2 1/2 years. Only problems I've had with the rallylights H4 upgrade kit are going through a set of bulbs about every 6 months, and rocks cracking or chipping the glass Hella housings.

Mike

The harness has the caps & resistors built in. The caps are just big enough to smooth out the pulses.

 

[lysol]

unless you can find a relay that works at a nominal 4v-15v, it will eventually get destroyed. I've mapped the duty cycle of the highbeam circuit on a o-scope and it goes from 4.6v to 12.6v. The 4.6 is miniscule but it matters.
I've obviated that with capacitors.
rallylights.com could build you a tap with everything wired it; they do great work.

What does the current look like as the PWM pulses the volts? Does it fluctuate as well?

 

[Hilldweller]

What does the current look like as the PWM pulses the volts? Does it fluctuate as well?

I didn't measure that but I'd guess that it's relative. Not sure that my scope could've grabbed that; I think my meter can but can only give a high/low and not log all the data...

I've had relays that weren't as sensitive as others. Some that didn't chatter but died young. Some that chattered and fried in a few minutes.
Here's something to hurt your head: http://www.te.com/commerce/Document...cNm=PWM_and_Auto_Relays&DocType=CS&DocLang=EN
And some practical chat: http://www.candlepowerforums.com/vb/showthread.php?263719-PWM-d-voltages-for-Automotive-lighting

 

[Alphonse]

I have had 2 sets of halogen auxiliary lights (kc 6" driving and kc 8" spots) wired to trigger off 2 standard kc relays (included with lights) by my high beams for 4 years in my 2011 JKUR with no issues. The factory system seems to trigger and hold constant on with these cheap relays just fine, lol

 

[kojackJKU]

Hi Alphonse, Mines a 2011 as well. I wonder did they change something in 2012? My HID and fogs are triggered from the stock system. I have no issues with my Relays etc either. hmmmm.

 

[lysol]

I didn't measure that but I'd guess that it's relative. Not sure that my scope could've grabbed that; I think my meter can but can only give a high/low and not log all the data...

I've had relays that weren't as sensitive as others. Some that didn't chatter but died young. Some that chattered and fried in a few minutes.

I've been reading through Hella's catalog of various relays around the 40-amp limit and I see they have some with diodes and others with resistors. I assume these are to protect sensitive electronics when the electro-magnetic field collapses when power to the relay is switched off. I wonder if the relays with resistors help with the PWM current?

 

[lysol]

Here's something to hurt your head: http://www.te.com/commerce/Document...cNm=PWM_and_Auto_Relays&DocType=CS&DocLang=EN

So I gather from that .pdf that the diode is the best and worst option? It helps keep the relay actuated, but can cause problems when the power is removed?

 

[Hilldweller]

So I gather from that .pdf that the diode is the best and worst option? It helps keep the relay actuated, but can cause problems when the power is removed?

It's just a gate.

Take a look at solid state relays too.
Or just call one of the electronic suppliers and ask. Like I said, some of the good ones maintain the field well enough through the cycle that it doesn't chatter. I'd personally build it with a cap and resistor but a cap and diode should work... ...or just a good relay.
The drop in power to 4.6v is so short in duration that it's nearly transparent. Nearly. And it happens thousands of times/second.
Technology is a PITA sometimes.

If you call Ray at Rallylights and tell him what you want, he'll make it for you and send it right out. I'm thinking of calling him and making an H13 to H13 with a dongle off the highbeam circuit with a cap/resistor for a set of driving lights. I don't want to guess that my relay is going to work; I'd rather know it will...

 

[lysol]

Anyone find a viable solution yet? I noticed that sPOD states one of their products works with PWM for the high beam trip wire.

 

[Alphonse]

Just an update. I posted earlier that I had no issue but now I have swapped my KC Halogen Lights to Baja Designs LED lights and there is noticeable flickering with them triggered by the high beam circuit in my 2011. I guess the instant on of the LED exposes this while the slower on/off cycle of the halogens hid it. I have some cheap anti flicker harnesses coming ($7.00 shipped on eBay) to try and address it. I believe the harness is just a couple capacitors will update this thread in the next week if this works for me. (If you are curious what I'm talking about search "anti flicker harness" on eBay and you will find many sellers offering the same harnesses for around $6-9 delivered.)

Btw the anti flicker harness has a black and red going into it and a black and red coming out of it. I'm guessing the black is just a through wire? There would be no reason to have the capacitors in the harness utilize the negative lead, correct?