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5 pin bosch style relay

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=130097
Printed Date: May 15, 2024 at 5:13 PM


Topic: 5 pin bosch style relay

Posted By: flyryde
Subject: 5 pin bosch style relay
Date Posted: January 07, 2012 at 8:25 PM

My goal, keep a wire from putting out any voltage until it sees 12 volts.

So this wire I'm messing with is putting out 4.5 volts.  I want to use a resistor to drop the voltage low enough, that it will not switch over the 5 pin relay.  When you turn the switch this wire is connected to, the voltage goes from 4.5 volts to 12 volts.

My theory is that I can drop the voltage using a resistor, so low that it wont energize the relay, and the relay will stay closed, but when the voltage jumps from 4.5 to 12 volts after turning the switch, the extra voltage will then trigger the relay, and direct voltage from the battery source will then flow out. 

Basically I dont want to see 4.5 volts ever, either 0 or 12.  I'm sure some of you know what I'm doing.  Please let me know your thoughts, and if its possible, what resistor I'd need to drop 4.5 low enough to not trigger the relay, but high enough that with the extra 7.5+ volts passing through with the switch turned WILL trigger the relay.

I know these 40 amp relays need very little voltage to trigger, but other than that, I have no clue about ohms or any of that.  Thanks so much ahead!

Chris




Replies:

Posted By: KPierson
Date Posted: January 07, 2012 at 9:35 PM
resistors resist the flow of current, the flow of voltage. A resistor can't be used to drop voltage in the manner you are trying. You would be much better off using some solid state devices like a comparator or an op amp to make a voltage activated switch. That switch then could drive the relay. Should not be hard to find schematics all over Google on how to do this.

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Kevin Pierson




Posted By: howie ll
Date Posted: January 08, 2012 at 2:05 AM
Standard relay triggering from 4.5 volts? I can't see that can you Kevin?

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: howie ll
Date Posted: January 08, 2012 at 2:12 AM
Just tried, 8.5 volts. That from a 35amp regulated variable voltage power supply.
Faint clicking at 7.5 volts though a 12v coil PCB style does work at 7.5 volts.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: oldspark
Date Posted: January 08, 2012 at 3:12 AM
Alas those voltages vary depending on the relay.
The usual relevant specs are "pull-in" or energising voltage and "drop-out" or release voltage.
(And though not relevant here, another important parameter is contact force versus voltage. Automotive and hi-current relays use high contact pressures to prevent "bumping" open or poor contact. Some people learn the hard way why NOT to drop 12V headlight or amp relay coils to 8V etc.)


But the OP is ambiguous.
The first line is simply +12V to turn on a relay to pass the 4.5V signal.
Later however it suggests some switch that turns 4.5V into 12V.

The latter can use a relay with higher than (say) a 5V drop-out/release voltage - and/or maybe with a diode or few or a zenor diode to drop the 4.5V to below the relay's drop out voltage.




Posted By: i am an idiot
Date Posted: January 08, 2012 at 4:27 AM

4.5 volts will not energize a Tyco relay, but it may be enough voltage to keep it energized when the voltage drops from 12 down to 4.5





Posted By: howie ll
Date Posted: January 08, 2012 at 4:35 AM
Craig, I didn't try that part.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: flyryde
Date Posted: January 08, 2012 at 11:37 AM

LOL, I felt like such a dork after posting this.  I didn't even think of how easy it is to test all of this theory.  I grabbed a 9 volt battery and hooked up a relay and was able to get it to energize.  Then I tried a 1.5v AA battery, nothing, added another AA, nothing, then tried another at 4.5v, again nothing.  Even 4 AA batteries at 6v didn't do anything more than create a very faint reaction, but didn't energize the relay.

I just did a test, and the relay on its own worked perfect!?

So long story short, I just posted before testing on a Lexus IS350.  Apparently everyone who wants to get rid of the ugly faint yellow glow coming from the high beam section (high beam bulbs running at 4.5v), has been told they need to go visit a dealer to reprogram the cars computer to disable the function.  Problem is, most dealers are morons or crooks, and very few are willing to work with the automotive enthusiast, especially not without some hefty costs in doing so. 

I'm working on the 4th IS right now, and I told the owner yesterday he'd have to go ask a dealer to turn of his sons DTRL function via their special hardware tool.  After I called him I just felt like nobody has really tried to tackle this thing.  Now I'm realizing that nobody facing the DTRL issue has made much effort to tell everyone how easy it is?

I opened the fuse box, followed the high beam wire to its source and about 6 inches up I cut the wire.  Meanwhile I had a relay (30 & 85) hooked up to the battery power and ground.  I put the wire putting out the 4.5 volts into my trigger (86) and the other end of the high beam wire, the one feeding the actual bulb, hooked up to 87.

Worked perfect.  When 4.5v was being putting out the relay was not switching, but when the full blast of 12v came into the trigger, the relay switched, giving a direct 12v from the battery (or 13.8ish really) to the high beam bulbs.  If you bothered reading up to this point, my question is, what advice can you give me for long term durability of this setup? 

 I'm sure I could tap into another cricuit for the power and ground for 30 and 85, but with the draw of a single 55w high beam halogen bulb, I'd feel more comfy with a 18awg fused connection to the battery directly.  Then an HID kit could even be swapped in there later and it'd work perfect. I think this method will work for every single car out there with Day Time Running Lights built in that power up the high beam bulbs at low voltage and look terrible.  I'm not just trying to remove the DTRL function, but rather enhance it.  Check out the video I posted last night showing the lights I added instead of the stupid dim high beam bulb :)

https://youtu.be/Nmup9fBGmC8





Posted By: howie ll
Date Posted: January 08, 2012 at 2:33 PM
Place a diode 1N4004 between 85 and 86 of the relay, band towards 86, this will negate any possible feedback, or stop DTCs being generated.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: oldspark
Date Posted: January 08, 2012 at 9:23 PM
... making sure 86 is +12V & 85 GND. (The diode's band is always the more +ve voltage when using it for this sort of protection. (Otherwise 12V will "short" to GND via the diode, and the diode goes pffft - if the circuit does not blow first!)


But the convention is 86 is the more +ve, and that's what professionals (lie Howie) and the experienced (like Howie) quote. (You'll notice all the12volt relay diagrams are 86 to +12V & 85 to GND.




Posted By: howie ll
Date Posted: January 09, 2012 at 12:58 AM
Actually Peter, they aren't, some of the drawings have the terminals reversed for convenience of circuit layout, whereas when I do my little drawings and try to keep to the 85NEG, 86POS convention, they end up looking like maps of London's Underground!
As Messrs. Idiot and KP will confirm ISO convention makes 85 NEG and 86 POS. That's how the car manufacturers wire them and as you know VERY relevant if inbuilt diodes or pre-dioded in the wiring looms as some car manufacturers loom them.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.





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