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LED noise question

Old 11-29-2017, 11:59 AM
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Default LED noise question

I am thinking of replacing my navigation lights with LED's. I want to replace the old style incandescent bulbs with the LED's that plug right in. I have heard that they can cause interference with other electronics such as MFD's and radio's. Has anyone had any experience with this?
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Old 11-29-2017, 12:29 PM
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I replaced ALL the incandescent bulbs on my boat. A few of the LEDs came from reputable suppliers, but most were via eBay.

I've had zero problems on my boat related to this change in the bulbs.
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Old 11-29-2017, 02:04 PM
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Ic you have truble with noise from led's i would try placeing a large electrolytic capacitor on the mains to filter out the noise. This would also help when a large load starts up such as a pump, amp or the motor.
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Old 11-29-2017, 06:42 PM
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They would have to be very leaky in terms of the driver. That and a bad non isolated ground. Also shore power with a charger can make them put out noise but again its fixable.
Caps can help but you have to be careful. If you arent running an engine and the caps discharges it will have a tough time replenishing as there is no recharge taking place. No issue on a car because of large alts always on but its the reason they are no seen on a boat.
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Old 11-29-2017, 08:41 PM
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Buy EMC certified lights (the two links below are not marine navigation lights, just info)
https://www.visionxusa.com/article/h...ertifications/ Lower right is an example of the certification
https://www.luminell.com/node/318

Here are some marine lights that are certified
http://store.marinebeam.com/led-navi...izontal-mount/
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Old 11-30-2017, 06:51 AM
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If they have an internal power supply that converts the 12vDC into something else, they can be prone to generating electrical noise, otherwise should be no extra elec noise. Household LED lights are notorious for generating electrical interference. I re-did a kitchen and can't use an FM radio nearby anymore. If you are concerned, buy one & hook it up to see what happens. Or ask the manuf if they have a (switching ) power supply inside.
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Old 12-02-2017, 06:15 AM
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Originally Posted by BadgerS View Post
Buy EMC certified lights (the two links below are not marine navigation lights, just info)
https://www.visionxusa.com/article/h...ertifications/ Lower right is an example of the certification
https://www.luminell.com/node/318

Here are some marine lights that are certified
http://store.marinebeam.com/led-navi...izontal-mount/
Yes, the constant current linear driver should have zero emissions.
Some linear regulators, however, are notorious for have RF immunity issues. Test with a HH VHF on transmit mode to check for this. Its a minefield!
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Old 12-02-2017, 08:37 AM
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Regarding LED lamps and operating a radio near them: there are two cases of interference:

--the LED lamps make radio-frequency noise that interferes with radio reception, and

--the transmission of radio-frequency signals from the radio interferes with the LED lamps.

The first case, LED lamps generating spurious radio-frequency (RF) noise, is perhaps the greatest concern. An LED lamp could generate enough spurious RF noise that reception of radio signals by your communication radio would be significantly affected; this could be a safety concern.

Typically one would not expect the flow of 12-Volt DC current through a diode-junction inside an LED lamp to produce much RF noise. You can operate LEDs directly from 12-Volts if you include a current limiting resistor in series. However, this is not a good method of conserving electrical energy, which is often the goal of using LED lamps in the first place. With a series resistor, most of the electrical energy in the circuit is consumed in heating the resistor and only a small portion goes to making light with the LED lamp. Accordingly, many LED lamps include an integral voltage convertor, shifting the 12-Volts down to much less voltage, just enough--a Volt or two--to power the LED.

Usually the noise is generated by an integral DC to DC voltage convertor. These devices use a switching voltage convertor, and to reduce size usually cannot have the necessary inductors or capacitors to filter out the noise. They become, in essence, little radio transmitters.

As for the other case, the radio signal interfering with the LED lamp, this should not happen unless the LED lamp is very close to the antenna of the radio. It is a general goal of any antenna installation for transmitting to get the antenna away from all other devices and in the clear, so typically the antenna won't be close to any LED lamps. This also helps on receive--the antenna should be far away from any LED lamps and their RF noise.

The exception to the physical separation of the antenna from LED lamps occurs when an LED lamp is used at the top of a mast and a radio antenna is also installed there. That co-location creates the possibility of interference in both cases, receive and transmit.
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Old 12-02-2017, 11:50 AM
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Even with the resistor, the LED will consume about 1/4 what an incandescent bulb will. The resistor is there so the circuit is not a dead short when the LED conducts
(lights). There are also advantages with bulb life, durability, and brightness when using LEDs.

An LED with a resistor does not generate RF noise. A resistor ladder can be used to reduce the voltage without using any active components.

You can always put one regulator in the circuit somewhere away from any devices susceptible to RF interference.

However, I doubt you will have any problems. LED lights you would use in your house are a completely different type of device and you should not be comparing something you'd use on your boat to household (120VAC) stuff.
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