Adding LED fixtures wiring question?

[er9]

Originally Posted by slowneasy

I would talk to the sales guy. The lights are designed to be run at a constant current and not at a specific voltage. I believe you will need a driver and separate wires as you suggested to properly install those LED fixtures. I see some 12 v DC input 700 ma output drivers doing a quick google search, but the sales guy can likely tell you exactly what you need without you having to do a bunch of research.

that was easy. didn't even think of searching for DC to DC. looks like that may let me use these free fixtures.

[er9]

Originally Posted by KP44

Sounds like two questions.

1 - You will do just as well to extend the existing wire. Or replace it completely with a new wire. It is not recommended to run two circuits from one breaker.
As for the breaker and wire: A 15 amp breaker is designed to protect a 14 ga or larger wire from overload (fire). If you use the 15 amp breaker, you must use >at least< 14 ga wire. Your LEDs will probably run fine on 16 ga wire. If you do use smaller wire, be sure to change the breaker to match >the smallest< wire you use anywhere in the circuit.

2 - If your LEDs are made for 12v, they probably are OK with from about 10v to 30v. You must wire the + to + and - to - or they won't light up. But there should be no reason to add a resistor unless your LEDs are made for lower than 12v.

Like others have said, I recommend replacing the bulbs throughout your boat with LED "bulbs". With LEDs, you can run all your lights with about the same amount of power it takes to run one old-style bulb. Unless you spend most time with shore power, LEDs are well-worth the effort and cost to install.

much thanks...yeah iv'e decided to pull all the old wire. I will probably keep the old fixtures but upgrade the wire to 16ga and replace the bulbs in the old fixtures with LED bulbs. I will add a couple of the new LED fixtures into the new circuit. unfortunately it seems the lights I have need/prefer a constant current and stepped down voltage. fortunately the drivers are available.

[er9]

Originally Posted by senormechanico

YOU NEED a driver for each LED.
If you hook those LED's up to 12 volts without a driver, you will see an instant BLINDING FLASH !!
Then, no light ever again from that LED.

that was going to be my next question....one for each of the new lights i'm adding? thanks.....they were free lights but they are nice....really don't want to fry them. i guess i should pay more attention to the guy in the shop who does all the wiring.

[Dougtiff]

The circuit breaker protects the WIRE not the light.

[TreblePlink]

There are two types of LED "lamps"

The kind that are simplest (I'll call them type 1) are typically several series / parallel LEDs that want to see about 9 volts, and have a dropping resistor in series to allow operation at 12 volts. These can be designed conservatively so they work fine from 11 to 15 volts. Advantages: they generate zero RF noise and are generally very reliable. Disadvantage: they are a bit less energy efficient than the other type, but since they use such low energy anyway, it doesn't make much difference.

Type 2: These include an internal DC-to-DC switching regulator to drop the voltage.
Advantages: More constant brightness over the voltage range, and a bit more energy efficient. Disadvantages: Reliability varies from decent to terrible. Many generate RF noise that can ruin SSB reception.

[er9]

Originally Posted by TreblePlink

There are two types of LED "lamps"

The kind that are simplest (I'll call them type 1) are typically several series / parallel LEDs that want to see about 9 volts, and have a dropping resistor in series to allow operation at 12 volts. These can be designed conservatively so they work fine from 11 to 15 volts. Advantages: they generate zero RF noise and are generally very reliable. Disadvantage: they are a bit less energy efficient than the other type, but since they use such low energy anyway, it doesn't make much difference.

Type 2: These include an internal DC-to-DC switching regulator to drop the voltage.
Advantages: More constant brightness over the voltage range, and a bit more energy efficient. Disadvantages: Reliability varies from decent to terrible. Many generate RF noise that can ruin SSB reception.

Do they only affect reception when they are turned on?

[TreblePlink]

Right. If they receive no power, they emit no RF noise energy.

[er9]

Originally Posted by KP44

Your sales reps are probably not a good source of specs. Ask the manufacturer. If that is not possible, find a HAM operator in your area and ask him for assistance. All you need to know is the voltage rating of the LEDs. Or use a volt meter and measure the voltage coming from the plug-in power supply. (It should say on the power supply.)
Remember - You are not using 120v AC so you should not need a regulator. You already have 10 to 15 volts from your batteries. That is probably perfect.

is that why you mentioned asking a HAM operator? because they would know which don't cause RF interference?

[TreblePlink]

Although I've been a ham since 73, I'm sad to say that with the current state of affairs I cannot suggest using one as an electronics or radio consultant. 90% don't even know Ohms law, let alone understand semiconductors or circuits. There are exceptions, but they're rare.

[KP44]

Originally Posted by Colin A

Looking at the spec for the driver the call out it looks like they run at 4-5VDC at a constant current so unfortunately you will need some kind of external driver.

This is a place for keeping things simple. LEDs are not expensive, unless you buy the expensive top-names. But buying LEDs that use 10v to 30v DC is inexpensive. I would recommend using only LEDs that fit your boat's existing electrical system.

[er9]

Originally Posted by KP44

This is a place for keeping things simple. LEDs are not expensive, unless you buy the expensive top-names. But buying LEDs that use 10v to 30v DC is inexpensive. I would recommend using only LEDs that fit your boat's existing electrical system.

Thank you I appreciate your input. i may go this route. the lights i have were free but they still would end up costing me $ to get them to work correctly. in the end it may just be simpler to buy good fixtures that will install with no additional requirements and may not really end up costing me that much extra...

[TreblePlink]

Originally Posted by KP44

But buying LEDs that use 10v to 30v DC is inexpensive.

Be advised that this is the type notorious for generating RF noise. Not all, but maybe 50%.

[senormechanico]

It'll cost you $1.75 to find out, but hurry. Only one left.

https://www.ebay.com/itm/3W-LED-Driv....c100507.m3226

Here are some others which might work as well:

https://www.ebay.com/itm/5Pcs-3W-5-3...MAAOSw4GVYSCwq

[TreblePlink]

That is just the switching dc-dc converter. You will also need the 3 watt LED, and do some soldering, make a housing, etc.

But that is the easy part.

At 3 watts and above, the thermal heatsinking requirements for good LED life are not trivial. I have had better luck using 10 watt LEDs and operating them at lower current so they run about 3 watts. But they still need a good heatsink.

3 watt heatsink:

https://www.ebay.com/itm/5pc-3W-Watt...item56a82f2970

By the way, those sort of cheap dc-dc converters are just the type (with fewest parts, omitting RF filtering, etc.) That generate RF noise.

[senormechanico]

The OP has already got the LED's as posted in the thread:

https://step1dezigns.com/led-mini-sq...recessed-light

I was just responding what he needed NOT to blow them to bits in a nuclear flash.

I'm also a HAM and am familiar with onboard RFI.
BlueSky 2512 iX, UltraSoniTec, are my gremlins, but I can live with them.