12v cobra light led
Printed From: the12volt.com
Forum Name: Lights, Neon, LEDs, HIDs
Forum Discription: Under Car Lighting, Strobe Lights, Fog Lights, Headlights, HIDs, DRL, Tail Lights, Brake Lights, Dashboard Lights, WigWag, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=126564
Printed Date: May 10, 2025 at 10:49 AM
Topic: 12v cobra light led
Posted By: cristu
Subject: 12v cobra light led
Date Posted: March 14, 2011 at 3:54 AM
Hello,
I have purchased an 12V cobra Light and I want to connect it to my car.
It says that I shoult connect the RED wire (+) to constant power (+) and the BLACK wire (-) to 12-volt positive ignition wire.
I want to use a 5-pin relay to prevent the battery drain.
Can you help me with the connections of teh relay and wires ? Some schematic diagram ?
Thank You.
Cristi
Replies:
Posted By: KPierson
Date Posted: March 14, 2011 at 10:57 AM
What is a 12v cobra light? How are you planning on using it?
From the wiring information it appears as if the light is on when the ignition is off. How were you wanting to use a relay to avoid battery drain?
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Kevin Pierson
Posted By: cristu
Date Posted: March 14, 2011 at 1:01 PM
Hello,
12v Cobra light is an 12V blue light display led - fake led.
I want to connect it to my car (I do not have an alarm system)
I do not know very well if I need an relay, that's why I'm asking you; some people complains about battery drain and I want to prevent this.
If you know a better solution I glad to hear you.
My concern is If I connect the + Red wire to plus permanent (=) and - Black wire to (+) ignition contact, so when I start the engine then the led stops blinking and when I stop the engine (remove the key from contact) the it goes to (-) ground and the led start to blinking.
I,m sorry about my poor english.
Here's the schematic for the led:
https://s576.photobucket.com/albums/ss202/cristu/?action=view¤t=Led.jpg
Posted By: KPierson
Date Posted: March 14, 2011 at 1:59 PM
That's what I figured.
You won't be able to lower the current anymore then what is necessary to power the led.
A super bright LED pulls ~25mA when on constantly. A relay will pull ~150-200mA.
Hook it up as directed.
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Kevin Pierson
Posted By: cristu
Date Posted: March 14, 2011 at 2:30 PM
Thanks
The LED specs says that it's pulls around 50mA.
I will connect it directly without any relay or resistor. I hope that will work.
Posted By: KPierson
Date Posted: March 14, 2011 at 2:54 PM
That's quite a bit. It won't drain your battery over night but expect the car to be dead if you leave it set for 2-3 weeks. ------------- Kevin Pierson
Posted By: oldspark
Date Posted: March 14, 2011 at 6:24 PM
Agreed, though maybe quicker (depending on the battery).
Normally flashing LEDs take MUCH less - even if supebrights. Thanks to PEAK higher currents at lower duty cycles (on times), they can take 10 or 100 times less than normal - eg a 50mA LED will only take ~5mA (depending on the flasher - forget using 555s (but CMOS 7555s maybe).
A relay won't save it.
You'd want some low voltage detection.
Or a separate (small) battery - but then it's almost cheaper buying an audio HU with a inbuilt flasher!
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