*WARNING*
This modification may be the cause of a battery drain problem I was having. Use this info at your own risk.
PROBLEM: My Elantra GT has an alarm, but no visual deterrent!
SOLUTION: “Install” a blinking red LED similar to those on other alarm systems.
MATERIALS:
1 - bright red 5mm Blinking LEDs:
1 - 470 ohm resistor.]
1 - 5mm LED holders from RadioShack: Item #: 276-079
misc. clips & wire.First I removed one of the dummy switch panel / place holders next to the panel dimmer switch. Use instructions similar to these by southpawboston. Next I soldered some wires to the LED and soldered them to some quick connect clips. Then I drilled a 1/4 inch hole into the center of the switch panel and inserted the LED and clip.
I was going to use a relay, but saw a great post on CandlePowerForums about a better / easier way to do this. A fellow CPFer, CNC Dan said, “Find a source of +12v that is on when the car is off.(clock power?) Then find a source of +12v that is only on when the car is running and always uses power.(daytime running lights? ignition?) Wire your blink led/circuit using the first wire as your POS. connection and the second wire as your NEG. connection. When your car is on both sides of your circuit get +12v so no current flows. Whe the car is off, the switched +12v goes to 0 volts and your circuit sees +12v and 0v and begins to flash.”
What I didn’t know was that the fuses could act as ground when they were not on. I did some tests with my multimeter and saw that everything would work as mentioned in the forum.
Here is my schematic:
Next I needed to tie into the fuses. I was about to run down to Radio Shack for some fuse taps, but decided to try simple wire wrapping… this proved to work very well. I soldered on the other quick connects and put everything together. I made sure everything was insulated with electrical tape and shrink tubing.
Here’s the final product:
Notes:The blinking red LED was designed to focus the light into a tight viewing angle (15 deg). This made the light very bright in one spot, but not very visible from the sides. I took it over to the grinder and removed the cone and flattened the top off the LED to make it diffuse the light. This worked GREAT.
Update:
*WARNING*
This modification may be the cause of a battery drain problem I was having. Use this info at your own risk.
Popularity: 22% [?]
December 26th, 2007 at 5:16 pm
Have you confirmed that this product caused a battery drain?
Thanks
December 26th, 2007 at 5:24 pm
Barry, I really with I had an answer for you. Unfortunately I wasn’t able to track down the issue and I haven’t had the guts to attempt it again. I’ll try to schedule some time to give it another go when I’m sure I won’t be needing my car… just in case I drain the battery.
December 26th, 2007 at 5:48 pm
Thanks for the quick reply.
I had ordered a “blinking” LED light with a red and black leads that had no instructions other than it was for an add-on to an existing alarm. I thought I could wire it the same as yours, but was wondering why you added a resistor.
Also, it seems that a light with little current draw would take forever to wear down the battery.
Thanks for any help you can provide.
Barry
December 26th, 2007 at 6:01 pm
Barry, LEDs will blow if you feed them the full 11 - 14 volts from your car battery. The red LEDs usually like to run at around 2 volts, so the resistor is necessary to reduce the flow.
The drain on the battery (if even related to this project) couldn’t have come from the LED alone, but would have come from the way I had this wired to the fuses.
February 18th, 2008 at 9:59 pm
what makes the 5mm led light blink ? where to buy it?
February 28th, 2008 at 6:20 pm
I’ve had a similar problem with an LED alarm light I hooked up to my daughter’s Scion XB The “fake” alarm LED light kit was purchased on eBay. I don’t recall it having any resistors, just three wires.
I have been having dead battery issues since I’ve installed it. Wouldn’t think that the LED would drain the battery after a couple of weeks, but it appear to be doing just that. Battery and alternator have tested good.
Has Rob determined if the LED was the source of his battery problem?
March 12th, 2008 at 9:15 pm
Gerardo: Do a search on ebay for “blinking red led” or something similar and you should find them.
Peter: I haven’t narrowed the power drain down to this modification yet. I rely on my car too much right now to even attempt it. I’d love to have someone with a bit more car electronics experience review my diagram to give feedback on if the way I have this configured is viable.
April 20th, 2008 at 6:47 am
The LED shouldn’t drain the car battery that fast, maybe after a couple of weeks continuous use, think about cars actually with alarms in them how come their batteries don’t drain down when they have the exact same LED constantly flashing, there must be another problem with your battery
April 20th, 2008 at 10:41 pm
James, you are spot on. A car battery has on average 45 amp hours (45,000 milliamp hours) and the little red LED uses at most 20 mA that means it could run for 2,250 hours straight, or 93 days, or 3 months!
My thought is that there is a problem with how the circuit is laid out specifically my use of the fuses to power and turn off the LED. I think something other than just the tiny LED is draining power.
April 22nd, 2008 at 5:45 pm
I was just reading these posts. I think the batter drain problem is caused by the way you have the circuit wired. You decided NOT to use a relay. Instead you went two existing circuits. While this approach may work, you don’t know what else is on those circuits and if their components are able to “handle” the fake ground you are causing them to imitate.
I had a similar blinking LED in one of my cars. I used a relay to power the LED when the car was off. It lasted for 5 years with no problems.
Bottom line is USE A RELAY!!!!! This way you are only tapping off of the battery’s power and not adding any other circuitry into the mix.
May 14th, 2008 at 2:25 am
I wanted the same fake alarm blinking led, went to Radio Shack and they fixed me up with the following parts and a basic wiring diagram:
blinking led 3.0-3.8 volt part no. 276-312
led holder part no. 276-079
270-Ohm resistor part no. 271-1112
12vdc relay part no. 275-241
soldered connections, used some heat shrink and all is working. Lights off when ignition switch is on and starts binking when ignition is off. Not sure how to post a picture on this site but if someone could tell me I could attach the diagram.
May 14th, 2008 at 10:03 pm
Michael,
Got the goods from radio shack. How is this all hooked up? Could you email a scan othis? To poorskinnywhiteboy@hotmail.com
June 12th, 2008 at 4:19 am
ok the proper way to do this is to buy a 12volt rated flashing led. Then mount it and run the positive lead to a constant power. Run the neg lead to prong 87a on a 5 pin relay. Run power with ignition to prong 85 run ground to prong 96 and 30. you now have a led that flashes with the car off and not while the car is on. Not you will have a ground on prong 87 only when the car is on.
June 13th, 2008 at 4:32 pm
I bought a blinking light with two wires attached, one goes to a push on/off switch and the other to a ground, from the switch one side to a power source and the other side is from the light as mentioned above, I have done this for years and have had no problems and no battery drain problem, maybe all the relays and resistors are your problem………
July 6th, 2008 at 3:32 pm
Michael,
Can you send me an email describing how to connect the wires to the 12vdc relay and where to put the resistor(s)? If I look at the bottom view of the relay I have two prongs on the upper left, side by side, and two on the lower left, side by side, and then one single prong on the lower right. Can you describe how to wire this up?
Thanks,
Greg