70 amp charger cooking 12v LEDs?

NinerBikes wrote:

Gdetrailer wrote:

DiskDoctr wrote:

Gdetrailer wrote:
I would suspect the resistance needed if any would be very small but if you like, instead of a resistor you can simply add a regular silicon power diode in series. A regular silicon diode will drop about .6V-.7V which would get you back to say 14.2-14.1V respectively.

I am planning to add a diode anyways to split the lights with a On-Off-On position switch.

Connect bulb Side A and Side B with a diode so that Side B is blocked from getting power from Side A, but flows freely from Side B to Side A (normal diode operation, but spelling it out here)

Position 1: Run 12v to switch, Power to Side 'A' lights only Side A, blocked by diode from running to Side B

Position 2: Run 12 to switch, Power to Side B lights BOTH sides, as power also flows through diode to Side A.

Have a wild guess as to a part number?

(probably wouldn't do any good in this position anyways :( )

Sorry, I'm not very sharp on electronics stuff this am

Pretty much ANY General purpose diode with a working voltage and amperage above what you expect to ever see.

A 50V 1A GP diode should be plenty acceptable if you are placing it in series with one of those modules.. You can find that as a 1N4001 which can be bought HERE, for 3 cents a piece (min order of 100 diodes at $3).

If you are planning to switch multiple lights then a higher current diodes would be suggested.. HERE is a 100V 6A diode at $.35 each..

Since the switching idea you are thinking of may possibly involve a fused circuit of 7A or more you may wish to consider using diodes with a minimum capacity of the fuse size so the fuse will blow instead of the diodes if any short would happen..

Higher voltage and current is OK but those do get physically bigger so there may be a point where too high of current or voltage diode may get difficult to fit in a small space.

Although, personally I would simplify things by using three and four way switching like you would find at a sticks and bricks..

Three way you need two single pole double throw (SPDT) switches, you would then need to run three wires between switches. One wire acts as a traveler and the other two alternate between on/off..

Found a good website with picture diagrams of three way wiring, just substitute 12V and 12V lights..

THREE WAY SWITCH DIAGRAMS

What is the voltage drop per rectifier with those models? 0.6 to 0.7V?

"Mex" sort of beat me to it a bit.

Silicon semiconductor "junctions" typically have pretty much similar forward voltage drop but not all will be identical even from the same "batch".

Pretty much accepted is a range from .6V-.7V depending on the current, this goes for silicon transistors and diode junctions..

While Mex quotes considerably lower forward voltage drop of .4-.5V for non Schottky diodes, I have never seen that low.. Typically .6V will be the lowest but that will be at the lower end of the current rating..

That 1A 50V PIV GP diode I linked has a .6V at min current to .8V at max current and the "typical" forward voltage drop per spec sheets is claimed as 1V.

For my own purposes I typically stick with .7V when using a diode as a means to quickly and predictably drop .7V per diode in series..

You can add additional diodes in series to drop more if needed.

As a side note, this is no different to what is done with White LEDs but instead of .7V per diode, White LEDs need about 3V average forward voltage.. Hence the reason for 12V you will typically find 3 white LEDs (approx 9V forward voltage drop) in series and a resistor or regulator..

For really cheap White LEDs modules they cheat further by using FOUR white LEDs in series and NO resistor or regulator for 12V!! While this is possible to do, it is not a recommended way if you want the LEDS to last..