Diode for Anchor/Steaming Light???

[Moontide]

Could just put the steaming/anchor light on a separate switch from the running lights. Just have to remember to flip 2 switches when underway.

[hzcruiser]

Originally Posted by Rumrace

Using a diode alone to stop the LED f[..]

Are you replying to a different post ?

[hzcruiser]

Originally Posted by mvweebles

I have a 36-foot powerboat with 12-volt systems. Note, regulations permit a single all-around steaming light for vessels under power below 12-meters (39-feet).

I would like to use a single all-around light as both anchor and steaming light. Occurs to me a diode of some sort will permit this - see the attached diagram.
[...]

What do you want to achieve with this? You're not saving a switch or a wire up the mast by using the diode, you're only making sure the all-round light comes on automatically with the side lights, correct?

[RaymondR]

The OP wants the all round white to go on with the port and starboard lights on one switch but not the port and starboard to go on when the all round is switched on.

[hzcruiser]

Originally Posted by RaymondR

The OP wants the all round white to go on with the port and starboard lights on one switch but not the port and starboard to go on when the all round is switched on.

Yes, he still needs both switches and wires, what's the gain?

[Rumrace]

There is no benefit. In fact the diode consumes energy adds another hot connection doesn’t save a cent. Was a great idea for a tungsten filament lamp doesn’t fit into the led world

[AKA-None]

Originally Posted by Moontide

Could just put the steaming/anchor light on a separate switch from the running lights. Just have to remember to flip 2 switches when underway.

Well what happens when both are switched on ant ties plus with negative?

[stormalong]

Originally Posted by Rumrace

There is no benefit. In fact the diode consumes energy adds another hot connection doesn’t save a cent. Was a great idea for a tungsten filament lamp doesn’t fit into the led world

Rumrace: The voltage is reduced by the LED driver to about 4.5 volts. The voltage drop of a Shottky diode is insignificant.

Originally Posted by AKA-None

Well what happens when both are switched on ant ties plus with negative?

AKA-None: Why would switching on both switches tie positive to ground? Only a wiring error would cause that.


Mvweebles is trying to reduce the chance of forgetting to switch on his steaming light. The proposed solution accomplishes that. I have spent many hours tweeking my boat so that things are automatic or simplified. The more complex something is the more important it is to simplify. Although it is not complicated to throw two switches rather than one things get forgotten. Having a switch labeled running lights should turn on all running lights. It is a definite improvement to simplify turning on the lights correctly.

[AKA-None]

Originally Posted by stormalong

Rumrace: The voltage is reduced by the LED driver to about 4.5 volts. The voltage drop of a Shottky diode is insignificant.


AKA-None: Why would switching on both switches tie positive to ground? Only a wiring error would cause that.


Mvweebles is trying to reduce the chance of forgetting to switch on his steaming light. The proposed solution accomplishes that. I have spent many hours tweeking my boat so that things are automatic or simplified. The more complex something is the more important it is to simplify. Although it is not complicated to throw two switches rather than one things get forgotten. Having a switch labeled running lights should turn on all running lights. It is a definite improvement to simplify turning on the lights correctly.

Mainly because the thread started out as a two wire light that works in either polarity but different lights are powered based on which was positive and which was negative
Or is this not the question that was being asked? Maybe I missed something somewhere

[stormalong]

Originally Posted by AKA-None

Mainly because the thread started out as a two wire light that works in either polarity but different lights are powered based on which was positive and which was negative
Or is this not the question that was being asked? Maybe I missed something somewhere

Well. Yes, you did miss something here. No where in the circuit shown in post #1 is the operation of the two lights dependent on opposite polarities for operation. That would be an either but not both on two wires design.

There was a different thread recently discussing using existing wiring to drive two different masthead lights, not at the same time. Perhaps you got the two threads confused.

[sailinglegend]

The only time you really needs diodes is when a compass light needs to be fed from the Running lights or the Tricolour lights.

My new boat compass light was initially wired from the Running lights so when we started sailing and switched to the Tricolour the compass light failed. Rewiring the compass light via diodes from both lighting circuits is a simply solution.

[Rumrace]

The diode is a choke driver so it uses energy to prevent the led from burning out but just barely. It’s the most primitive way possible to run an led. The led will never run at the designed lumen output and burn up with incandescent speed.
It’s like the old 60% efficient dimmers. They work and some jerks still sell them.

[rslifkin]

Originally Posted by Rumrace

The diode is a choke driver so it uses energy to prevent the led from burning out but just barely. It’s the most primitive way possible to run an led. The led will never run at the designed lumen output and burn up with incandescent speed.
It’s like the old 60% efficient dimmers. They work and some jerks still sell them.

In this case the diode wouldn't be used as an LED driver though. The light already has a driver. The diode is only to prevent back-feeding one light from another to allow more flexibility in the switching and wiring configuration. There are ways to avoid needing it easily in this situation, however.

[Rumrace]

I understand yes.
These piece check all the boxes.
I have spreader lights from another company

[rslifkin]

Originally Posted by Rumrace

I understand yes.
These piece check all the boxes.
I have spreader lights from another company

The OP already indicated what light setup he has and intends to use. He's not going to buy new lights to save use of a diode or slightly more complex switch setup...