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Can't set amperage on 400w 15A DC-DC step up boost converter 10-60 volts

jobee

Mar 10, 2023
3
Joined
Mar 10, 2023
Messages
3
Hello folks,
I'm just new to the forum. I'm looking for help using a 400w 15A DC-DC step up boost converter 10-60 volts.
I watch many youtube video of people who can set voltage and amperage with that.
But I can't do the same. Here is my project : I want to power a COB LED 30-34v 200w.
I have a DC Power 28 volts 400 w that I plug to the DC-DC step up boost. I can set the voltage to 33V using my multimeter.
And after when I plug the COB LED with the multimeter as amperemeter it's not working. Actually there current is going to the LED but the voltage is blocked at 28 volt and amperage to 4A. If I turn the small screws on the Convverter, nothing happens.
I attached two drawings to explain it. (Not very technical drawings:)
Could you please give me help !

Jonathan
 

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bertus

Moderator
Nov 8, 2019
3,393
Joined
Nov 8, 2019
Messages
3,393
Hello,

Leds are current controlled elements.
It will not work correctly when you control the voltage.

Bertus
 

Bluejets

Oct 5, 2014
7,094
Joined
Oct 5, 2014
Messages
7,094
I suspect your input voltage is not high enough............not all be-all-end-all when they say 8.5 to 50v in for 10-60v out.
Try higher input and see what happens.

As a pre-requesit, play around with some of the smaller boost converters at lower voltage requirements and see what the outcome is there.
 

jobee

Mar 10, 2023
3
Joined
Mar 10, 2023
Messages
3
Hello,

Leds are current controlled elements.
It will not work correctly when you control the voltage.

Bertus
Yes, thanks exactcly. That what I understood thanks to people from this forum https://forum.allaboutcircuits.com/
Here is the procedure I followed to succeed.

1/ Set your converter for maximum-Voltage, and minimum-Current
BEFORE You turn the Power-Supply "On"."
2/ Turn On the power supply
3/ Slowly increase the Current-Potentiometer.
at some point, the LEDs should start to get bright.
STOP,
4/ Turn "Off" the Power-Supply.
5/ Connect an Ammeter between the Power-Supply and the LEDs.
6/ Turn the Power-Supply "On".
7/ Increase the Current-Potentiometer until the Ammeter reads the Current that You want,
but DO NOT exceed the recommended Current rating of the LEDs.
 

jobee

Mar 10, 2023
3
Joined
Mar 10, 2023
Messages
3
I suspect your input voltage is not high enough............not all be-all-end-all when they say 8.5 to 50v in for 10-60v out.
Try higher input and see what happens.

As a pre-requesit, play around with some of the smaller boost converters at lower voltage requirements and see what the outcome is there.
Hey thanks a lot
Finally the input voltage is high enough.
I fand the solution in this forum https://forum.allaboutcircuits.com/
This is because I didn't followed the right procedure.
Here is the procedure I followed to succeed.

1/ Set your converter for maximum-Voltage, and minimum-Current
BEFORE You turn the Power-Supply "On"."
2/ Turn On the power supply
3/ Slowly increase the Current-Potentiometer.
at some point, the LEDs should start to get bright.
STOP,
4/ Turn "Off" the Power-Supply.
5/ Connect an Ammeter between the Power-Supply and the LEDs.
6/ Turn the Power-Supply "On".
7/ Increase the Current-Potentiometer until the Ammeter reads the Current that You want,
but DO NOT exceed the recommended Current rating of the LEDs.

Best regards
 
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