Printer Friendly Forum Posts - Help with diode calculating

Hello

I am going to connect a alarm to the blinkers/side repeaters. In total it is 6 bulbs, 3 on left and 3 on right side.

Can you please correct me if i am wrong.

I found out that the wattage of the bulbs are 21w(back)+5w(on the side)+21w(on the front)=47 watt on each side. Total of 96w.

I need 2 diodes. 47w /12v=3,91 ampere each side.

So i need two 6 ampere diodes.

Is two P600M okay?

Sombody told me that it was enough with two 3 ampere 4001 diodes.

Why do you need the diodes?

-------------

KarTuneMan wrote:

Why do you need the diodes?

Because this is my turning indicators and alarm has only one output for flashing lights. If i don't use diodes and want to turn left, then both left and right turning indicator will blink at the same time.

exsodius wrote:

If i don't use diodes and want to turn left, then both left and right turning indicator will blink at the same time.

If you connect the light output wire to the "marker lights" or "corner lights" then I think you would only be hooking to 1 wire and wouldn't need the diodes. You do realize that when the alarm system is going off or is triggered that it will turn the light output on and off continuosly right? In other words, you don't have to connect to your turn signals to make the lights blink. The alarm will do the blinking of the marker lights for you. It's up to you if you want to do the extra work but it isn't really necessary.

iskidoo

seems like somthing went wrong with your post

Try reading it again...it should be there. What is the make/model and year of your vehicle anyway?

iskidoo wrote:

exsodius wrote:

If i don't use diodes and want to turn left, then both left and right turning indicator will blink at the same time.

If you connect the light output wire to the "marker lights" or "corner lights" then I think you would only be hooking to 1 wire and wouldn't need the diodes. You do realize that when the alarm system is going off or is triggered that it will turn the light output on and off continuosly right? In other words, you don't have to connect to your turn signals to make the lights blink. The alarm will do the blinking of the marker lights for you. It's up to you if you want to do the extra work but it isn't really necessary.

First it isn' really a alarm. I dont know the word for it. All it does is to open doors, trunk and blink lights with a remote. Its a aftermarket keyless entry system i think its called. Second i dont have marker lights at all here in norway. So basicly the only choice i have is the turning indicator lights or the dome light.

Car is a 2002 ford focus wagon.

Are the 2 sets of wires GREEN/ YELLOW & GREEN/ blue? You can also use a relay. Run one set of lights to the light output and use a relay to power the other set of lights. If you trigger your relay coil with the same light output wire, I don't think they would conflict with one another. Just a thought.

exsodius wrote:

In norway parking lights is 2 little bulbs with white light inside the headlights, and the rear red driving lights. When all these 4 bulbs are lit, we call them parking lights.

What's wrong with just using those lights? Is that just one connection to light all of them?

iskidoo wrote:

Are the 2 sets of wires GREEN/ YELLOW & GREEN/ blue? You can also use a relay. Run one set of lights to the light output and use a relay to power the other set of lights. If you trigger your relay coil with the same light output wire, I don't think they would conflict with one another. Just a thought.

Yes there is 2 sets of wires blue and blue/green for the indicators left and right circuit. And yes i could use a relay. But if i dont have to, i would rather use diodes if its ok.

Regarding to my first question at the top. Are my calculations right? I have already connected it that way and it works. All my indicators blink with a touch on the remote. The only problem is that i have installed two 1 ampere diodes and they get extremly hot only in 10 seconds.

iskidoo wrote:

exsodius wrote:

In norway parking lights is 2 little bulbs with white light inside the headlights, and the rear red driving lights. When all these 4 bulbs are lit, we call them parking lights.

What's wrong with just using those lights? Is that just one connection to light all of them?

No its two circuit. And another thing we have in norway by law is something we call automatic driving lights. So when i start the car the headlights automaticly turns on. I dont ever have to use the light switch, exept at night when i want my long beams on.

So i cant use the "norwegian parking lights" because the automatic driving lights turns on when i only connect to the "norwegian parking lights".

]So i wrote:

cant use the "norwegian parking lights" because the automatic driving lights turns on when i only connect to the "norwegian parking lights".

If it's only to indicate that the signal was recieved by the remote then why not just use the norwegian PK Lights? How many diodes do you have? you could use more than 2 if you have them.

iskidoo wrote:

]So i wrote:

cant use the "norwegian parking lights" because the automatic driving lights turns on when i only connect to the "norwegian parking lights".

If it's only to indicate that the signal was recieved by the remote then why not just use the norwegian PK Lights? How many diodes do you have? you could use more than 2 if you have them.

I have two 1 amps. But is there a reason for avoiding the turning indicators? Here all cars use them for their alarms and remotes for indication of arm/disarm, lock/unlock.

No reason not to use them. I'm just trying to keep you from burning up diodes. If you can get a few higher amperage diodes (like 6amp) you'll be better off and they won't get hot. I asked if you had more 1 amp diodes because you could have twisted like 3 together(band facing same direction)
and used it as one for each light circuit for a total of 6 diodes. The 3 twisted together on each end would have given you 3 amps for each wire thus preventing them from getting too hot. Anyways, either get a few more 1 amp diodes, or a few higher amperage diodes you should be fine. Have a good night.

Best of luck, Steve

iskidoo wrote:

No reason not to use them. I'm just trying to keep you from burning up diodes. If you can get a few higher amperage diodes (like 6amp) you'll be better off and they won't get hot. I asked if you had more 1 amp diodes because you could have twisted like 3 together(band facing same direction)
and used it as one for each light circuit for a total of 6 diodes. The 3 twisted together on each end would have given you 3 amps for each wire thus preventing them from getting too hot. Anyways, either get a few more 1 amp diodes, or a few higher amperage diodes you should be fine. Have a good night.

Best of luck, Steve

Ok, i see. Yes they will burn up. 3 together its a paralell connection you are talking about. I would really love to get it work. I think i will go and buy two 6 amp diodes tomorrow. I am pretty exited if they will get hot too.

Also the seco-larm mounting insruktions say that "do not connect to headlights, it may cause a fire".

I will report back when i have tried this.

Thank you very much.

And have a good night.

So today i bought two 6 amps P600M diodes. I used a soldering shrinking plug at each side of the diodes. Worked great! Did not use any tape to isolate as the shrinking went all the way into the diode.

Just installed them on my 3.9 amps current circuit. Result, now after 15 seconds with all my turning inticator lamps on, diodes still get hot. But not as hot as the 1 amp diodes i used before. No smoke from them now :) So i now have diodes 6 times as powerful as the first ones.

So is it so that all diodes get warm like resistors? Is this normal.

I think i am on the safe side now that my diodes has a over capasity of (6 -3.9amp=2.1amp over capasity)

cut the wire before the diodes and the lights. Put your meter in line to measure exactly how much current is flowing in that circuit. Seems to me that it might be more current (amperage) than your calculations figured out to be. I've never had to use diodes on the lights before either so maybe they do get that hot.

iskidoo wrote:

cut the wire before the diodes and the lights. Put your meter in line to measure exactly how much current is flowing in that circuit. Seems to me that it might be more current (amperage) than your calculations figured out to be. I've never had to use diodes on the lights before either so maybe they do get that hot.

My calculations was based on looking over all the bulbs wattage. But if there is something wrong it could be more current.

A friend of mine said diodes are like resistors they do get warm. I don't thm i can use my multimeter for that, i think i must have a ampere meter?

Diodes have a voltage drop of about 0.8 volts. So if your current is 3.9 amp, you are disipating 3.12 Watts. This is heat that will warm up your diodes. So some diode heating is normal.

https://www.diodes.com/index.php

All the answers and MORE........

-------------

< =text/>showProduct( '28009', null, null );

Catalog P/N	Scroll to view Configuration	Max Average Rectified Current I_O (A)	Peak Repetitive Reverse Voltage V_RRM (V)	Peak Forward Surge Current I_FSM (A)	Forward Voltage Drop V_F (V)	@ I_F (A)	Max Reverse Current I_R (µA)	@ V_R (V)	Total Capacitance C_T (pF)	Package Outline
6A10	Single	6	1000	400	0.9	6	10	1000		R6

Can someone please explain all this numbers?