feuss2

iTrader: (1)

[youtube]CoQ2Q8Vte6E[/youtube]

LED's are 5 chip 100mA cool white

Constant power is tapped from the radio amp harness

Power to the storage pocket light clicks a SPDT relay to switch from the courtesy light circuit to ambient when lights are on

Ambient mode lighting is adjustable from under 1mA to about 40mA

aCUREa

I'm not sure I understand what the relay does. Can you post a circuit schematic?

feuss2

iTrader: (1)

There are some other threads on footwell lighting. They seem to be either courtesy or ambient lighting. This does both.

The relay switches between the circuits. +12V constant power stays connected to the LED's. The courtesy light circuit connects to ground through a transistor that does the dimming. When the lights are on in the car, the relay clicks over to connect the LED's to ground through a resistor that limits the current to the LED's to about 40mA max. You can turn it down below 1mA with the pot...

aCUREa

What kind of suppression device did you use in the coil circuit? Did you wire your own component (diode or resistor) across the coil, or did your relays come with internal suppression circuitry?

Just wondering

feuss2

iTrader: (1)

There is a 1A fuse inline with the connection to constant +12V!

aCUREa

Thanks for the schematic, and good work on that design

Just remember that inductive coils (like that of your relay) can generate EMFs upon opening of the circuit. This can damage your circuitry if not suppressed properly. I'm not sure if the LED/resistor pair in the storage pocket counts as a suppression device though. It seems to just be another LED for the center pocket light.

I'm assuming the triangles with lines are LEDs. That's actually the symbol for just a regular diode, not an LED. But it seems as if they're really LEDs.

Look here to see what I mean:
http://www.gcsescience.com/pecso.gif

The reason I bring it up is because if they are LEDs, then it seems as if you have no suppression device around that coil. I would add one. The best solution is to buy 'suppressed' relays that come with internal circuitry for this, but you can also wire in your own diode. Since you already have the relay, then just get yourself a 1N914 diode (the 1N4000 series will work too). Either way requires extreme care to orient the diode to face the + side, and in parallel with the coil.

Here is some info on counter-EMFs that your relay coil can generate (scroll down until you see "quenching diodes").
http://www.bcae1.com/relays.htm

http://www.candlepowerforums.com/vb/...61#post3311761

http://www.electro-tech-online.com/e...tml#post875711

A PDF one:
http://relays.tycoelectronics.com/ap...fs/13c3311.pdf

feuss2

iTrader: (1)

I can't tell if you were really interested in this or just looking for someone's work to correct. It seems to be the latter...

Let's keep in mind that the surge that results from cutting power to an inductive load is proportional to the product of the inductance of the coil and the current flowing through it.

In this circuit, I have used a very small (PCB mount) relay, with contacts rated for 1A. Both the inductance of this coil and the current going through it are significantly less than the 30A relays you used in your DRL headlight mod. This means that the surge/spike, etc could be orders of magnitude in difference...

If the voltage of the surge is less than the forward voltage of the diode, or if the surge is too short in duration for the diode to begin to conduct, the diode offers no protection!

The diode would have to have the anode on the ground side to offer protection.

Are you really uncertain? "LED replaces bulb in storage pocket" isn't clear enough?

This would be the reason I said "It seems to be the latter..." above!

An LED is a diode. It is a specific type. Again, the symbol for a diode with a text label "5 chip 100mA LED's" should get the point across. It's an unnecessary "correction" because there's no possible misunderstanding to clear up!

The circuit has no suppression because of the way the LED is wired in the circuit. LED's could be used as suppression devices, they almost never are because diodes with a lower forward voltage and higher max current do the job better.

I know you would, but there's no guarantee it is functional or necessary. Have you looked up the specs on all the relays the car was shipped with? You might find more that are unsuppressed. You should put diodes on all those before you worry about this micro-relay with 1A contacts!

aCUREa

Hey man, I'm just offering what I know. I didn't know you knew a lot about this... most people don't. I've seen people screw up with this before. I would have wanted people to comment the same way for me if I would have posted the mod. I'm just following the rule that most people I encounter on non-electronics forums don't know about EMFs, so I simply let them know the little I know about it. Plus, all the links I provided could help other members who view your thread as well.

The parklight circuit part of your diagram was unclear to me. Since the + and gnd are not labeled, and since the symbol is a diode without the label the other diode symbols got, it looked to me like the diode/resistor pair could either be a suppression device or just another light... that's all.

And obviously I am interested in your mod... just not the way most people are. I'm more interested in the way you did it technically... how you handled the suppression, etc.

Anyway, I'm glad to hear you handled the EMF thing well.

No hard feelings, and thanks for the reply.

ps, maybe you could provide for me some links about EMFs if you know of any. I'd like to read more about them myself.