dimming LEds

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pampas

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12 Volt 8 Amp For LED Lights Strips PWM Dimming Controller .
Has anyone fitted one of these units on a vessel.

Reading the specs there is no mention about the input voltage tolerance, need to dim the cockpit lights (Power boat), I assume the input needs to be stabilised.

Its a nice compact little unit quite cheap and would serve my purpose. Would appreciate anybody's experiences of these systems.

These items are sold via eBay
Pampas.
 
8 Amps @ 12v (96w) ...I hope you don't have that much LED lighting in the cockpit:D

I suspect that it might struggle to effectively control the (very much smaller) current that your LEDs probably consume. (How many/what power LEDs do you have?)

I would start by simply experimenting with a few fixed resistors in series with the existing lights (values in the 10 - 200 ohm sort of range).
 
These controllers will work at lower than 8 amps load and are fine up to 15v so you will have no particular trouble. Not good if your using a higher voltage charge controller though.
The PWM units are normally a 555 chip driving some MOSFETs so not complex. It's cheap so not much to lose. If the unit had the 555 powered through a regulator then the high voltage wouldn't be a problem either.
Resistors will overheat unless high wattage and heat sunk so don't do it.
 
Hy all, i suppose that your circuit is driven by Mosfet, and the 8 Amps is the maximum current that can be supported by the led driver. The driver had heatsink?

What buttons had?

What kind of led they are?

You should know that the maximum power dissipated in heat is achieved at the minimum light, because an amount of power should be dissipated in the Mosfet transistor.

Best regards!
 
Resistive current limiting can work assuming that the LEDs in the instruments are resitively current limited. (rather than with an electronic current control or regulator. These will try to maintain full brightness at any input voltage) They are almost certainly resistive current limited.
Typically your total instrument lighting might be 200 ma. (1/5 amp).
Typically you might want to dim to 100ma. About half brightness or power.
Assuming that the LEDs are in lots of 3 in series then total series resistor will look like about 20 ohms. It may consist of several different lots of series resisor and 3 x LEDs.
So another 20 ohms in series would be starting point for experimentation. Have a switch to switch in or out. (bypassed or not)
The added 20 ohm resistor will dissipate .2 watt. dropping 2 volts. A one watt or even 5watt wire wound resitor will be very cheap and not get too hot. The physically bigger the resistor the higher power rating and lower the temperature.
It is difficult to predict exactly what brightness you will get or degreee of dimming becuase LEDs operate ina very non lionear manner when relating current to voltage. This non linearity is made less by the series resistor. If each individual lED has its own series resitor then they can be quite linear compared to 3 LED ins series for more efficency.
So what you should do as Vic mallows suggested is buy a range of resistors and try them. The higher power rating being more robust but being heavier will need good mounting to resist vibration and lead fatigue. good luck olewill
 
Thanks for all of your advice. bit the bullet and bought one of these cheap dimmer units, works a treat and no RF.noise, Thanks again
 
VicMallows said:
8 Amps @ 12v (96w) ...I hope you don't have that much LED lighting in the cockpit:D

I suspect that it might struggle to effectively control the (very much smaller) current that your LEDs probably consume. (How many/what power LEDs do you have?)

I would start by simply experimenting with a few fixed resistors in series with the existing lights (values in the 10 - 200 ohm sort of range).
Click to expand...

That's not how you dim LEDs.

You flash them on and off above the human visual flicker rate adjusting the dury cycle.
 
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