current draw of LEDs

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=31333
Printed Date: July 19, 2025 at 7:19 AM

Topic: current draw of LEDs

Posted By: Pooreclipse
Subject: current draw of LEDs
Date Posted: April 30, 2004 at 12:11 PM

I have a couple of LEDs I want to hook up for "domelight supervision"

This is the specs here.

https://www.superbrightleds.com/T13_specs.htm

If I understand correctly each LED draw 40 mA ? (forward current..??) My domelight wire is low output and only 200mA.

BTW. What is the correct way to hook up 2 of these LEDs.

If you just joint the ground and + together on each LED, wouldn't only one go on at a time?

Replies:

Posted By: eurotech
Date Posted: April 30, 2004 at 12:59 PM

hook your domelight supervision output to a relay, I imagine that it is a negative output- then send a full 12 volts to your led's. if you hook them up in parallel (as mentioned) they should both come on at the same time. Good luck!

Posted By: Pooreclipse
Date Posted: April 30, 2004 at 1:02 PM

I know.. but I am trying to save a relay (less wiring) because if I don't have to, why bother?

It sounds like the draw is 40 mA and the output can support 200 mA... two LEDs take 80mA only, right?

Posted By: capple
Date Posted: April 30, 2004 at 1:20 PM

Yes I would go ahead and hook it up as you want to. You are correct in that the total current is 80mA

Posted By: mikej9881
Date Posted: April 30, 2004 at 2:32 PM

most outputs from alarms for domelight supervision is a negative output so you have to use a relay to convert polarity. unless maybe you power the leds and then hook the ground side straight to the negative output of the alarm but ive never done that so.....

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mike

Posted By: Pooreclipse
Date Posted: May 03, 2004 at 3:46 AM

Ok, I have made a relay for it anyway.

My question is, I have merged the 12V and ground wire for both LEDs at one point,

so they are in parallel.

My question is wouldn't my LEDs now become half as bright?? since they share the current in parallel?

Posted By: capple
Date Posted: May 05, 2004 at 2:22 PM

Simply stated NO the main power wire will have 80mA the branch circuts will have the 40mA each.