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Breaker Panel Label Back Lights

David Crisp
 

Sharing some info' for the benefit of those folks who are wanting to fix the back lights that illuminate the breaker panel labels.  

Almost none of the LED’s back lighting the breaker panel labels on my Amel 54 were working.  I was going to buy individual LEDs and fit fresh myself but in the event Amel provided complete replacement PCBs (with LEDs mounted) – thank you Sonja.

 

What I did learn from an electrician who has fitted individual replacement LEDs is that they are ~3.2V 1.0 – 1.2 cd (depends how bright you want them) blue LEDs he thinks they each draw about 20mA.

The electrician spent a day changing all the blue LED for red at the request of an owner.

 

For each label there is a pair of LED and resistor fitted in series. This means only one LED needs to fail and a pair will stop working. 

An individual LED costs ~1Euro.  

--
David Crisp
SV Wilna Grace
Amel 54 #58

Arno Luijten
 

Hi David,

The problem is that the blue lights are switched via resistors. Blue LEDs are by their nature very sensitive to overvoltage. You should supply LEDs ideally with a current source instead of a voltage source. A current source supplies a certain current and regulates the voltage to get to that current.
Using resistors is (especially) for blue LEDs a poor choice as your supply voltage can be anything from 24 to 29 volt. For a blue LED this means that when you pick a resistor suitable for 29 Volt, the thing will hardly light up at 24 volt. Picking a resistor for 24 Volt will fry the LED at 29 volt. This is why these switch panel lights die.

What I've did is count the number of LEDs (pairs) you need, multiply this with the optimal current for each pair of LEDs. The pairs are set in series on the PCB so the optimal current for one LED is the same as for the pair. I'm not sure anymore but I think I got to 500 mA for the lot. Then I bought a converter similar to this one from Amazon: https://www.amazon.com/Power-Supplies-25-2W-15-50V-500mA/dp/B00HKJAW20/ref=sr_1_63?crid=3YQWWEX2UH14&dchild=1&keywords=constant+current+led+driver&qid=1596040540&sprefix=constant+current+%2Caps%2C266&sr=8-63
This is a constant current supply to feed all the leds (in pairs). This has been working excellent for some time now. Each individual LED is fed their optimal current. I can't find the LEDs anymore that I bought from Amazon at the time, but I bought them in small bulk similar to these https://www.amazon.com/100pcs-Ultra-Bright-Emitting-Diffused/dp/B01GE4WEGI/ref=sr_1_8?dchild=1&keywords=blue+LED+5mm&qid=1596041080&sr=8-8

Hope this helps,

Arno Luijten
SV Luna,
A54-121

Gregory Shea
 

Arno, 
Is the constant current driver you linked to at Amazon suitable for us? It’s input voltage is 90-264 AC.

Greg Shea
Sharks 133 Cap des Iles 
Preveza

On Jul 29, 2020, at 12:46 PM, Arno Luijten <arno.luijten@...> wrote:

Hi David,

The problem is that the blue lights are switched via resistors. Blue LEDs are by their nature very sensitive to overvoltage. You should supply LEDs ideally with a current source instead of a voltage source. A current source supplies a certain current and regulates the voltage to get to that current.
Using resistors is (especially) for blue LEDs a poor choice as your supply voltage can be anything from 24 to 29 volt. For a blue LED this means that when you pick a resistor suitable for 29 Volt, the thing will hardly light up at 24 volt. Picking a resistor for 24 Volt will fry the LED at 29 volt. This is why these switch panel lights die.

What I've did is count the number of LEDs (pairs) you need, multiply this with the optimal current for each pair of LEDs. The pairs are set in series on the PCB so the optimal current for one LED is the same as for the pair. I'm not sure anymore but I think I got to 500 mA for the lot. Then I bought a converter similar to this one from Amazon: https://www.amazon.com/Power-Supplies-25-2W-15-50V-500mA/dp/B00HKJAW20/ref=sr_1_63?crid=3YQWWEX2UH14&dchild=1&keywords=constant+current+led+driver&qid=1596040540&sprefix=constant+current+%2Caps%2C266&sr=8-63
This is a constant current supply to feed all the leds (in pairs). This has been working excellent for some time now. Each individual LED is fed their optimal current. I can't find the LEDs anymore that I bought from Amazon at the time, but I bought them in small bulk similar to these https://www.amazon.com/100pcs-Ultra-Bright-Emitting-Diffused/dp/B01GE4WEGI/ref=sr_1_8?dchild=1&keywords=blue+LED+5mm&qid=1596041080&sr=8-8

Hope this helps,

Arno Luijten
SV Luna,
A54-121

Arno Luijten
 

Sorry my bad. There are just too many of these things. You cannot use the constant current source I mentioned earlier.

This one should work, depending on your LEDs of choice (total current of LEDs must match the Current Source):
https://www.amazon.com/LuxDrive-Wired-BuckPuck-Constant-Current/dp/B00LWU1EJS/ref=sr_1_1?dchild=1&keywords=LuxDrive+Wired+BuckPuck+-+500mA&qid=1596065887&sr=8-1
It may actually be the one I've use myself. I can't remember and the boat is 800 km away at the moment...

Sorry for the confusion,

Arno

David Crisp
 

Thanks Arno,
Excellent information and advice, makes sense to me.  I have only a very moderate knowledge of electronics and was wondering why the LEDs failed in the first place and how to prevent a re-occurrence. Judging by the colouration of one PCB it looks like the resistors had at some time got pretty hot, presumably when the voltage got high..
--
David Crisp
SV Wilna Grace
Amel 54 #58

Arno Luijten
 

Hi David,

Because of your remark I just remembered something about this. When I repopulated the PCBs with new LEDs I also replaced the resistors.
When you buy this package from Amazon: https://www.amazon.com/microtivity-IL142-Diffused-Blue-Resistors/dp/B0059H5Z5O/ref=sr_1_24?dchild=1&keywords=blue+led+5mm&qid=1596107237&sr=8-24
you get the LEDs with a resistor. If I remember correctly this was the actual package I bought. You will need three packages and have a lot of spares after installation. I replaced the existing resistors with the new ones. It will increase the voltage output for the regulator compared to no resistor and make it more stable.

Apparently these LEDs take 20 mA each. So two in series for every switch is still 20 mA. Multiply this by the number of panel switches which I think are 34. So, 34 x 20 = 680 mA. So at 500 mA they will receive about 15 mA.
I don't remember exactly but I think I was happy with this from brightness point of view. So I kept it at that as this will improve the life-span of the LEDs even more.

Regards,

Arno Luijten
SV Luna,
A54-121