campus189
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That's good information. Apparently the Vf is a little higher than 3.2V even but something isn't right. With this setup running, what's the supply voltage from the converter?
The numbers suggest that you only have one resistor connected (≈5Ω).
Okay, that's too much current so Vf is going to be 3.1V and the correct resistor value will need to be 4.3Ω for that supply. The resistor would be dissipating almost 1W of waste heat.
That would work but as you know now, since someone spilled the beans early, you can reduce the output voltage of the converter to a value much closer to what your LEDs want and significantly reduce the amount of power wasted in a resistor. This modification would require you to remove and replace 1, possibly 2 SMD resistors on the converter board.
How do you want to proceed?
I have no problem replacing the SMD resistors, there so damn small though
And question is, will we get the correct ones ? lol
Chinese foolishness. Can you measure R2 and R3 in circuit on the 472/188 board. Measure both directions as there may be some interference from other components.
Those resistors in your edit are 1.5Ω.
That's interesting. I kind of expect they're 4.7k and 1.5k. Take another look at R3. Could it be 153? I might need a picture.R2- 4.25k Ohms - Other direction 2.05k Ohms
R3- 1.45k Ohms - Other direction 1.31k Ohms
I volunteered and nothing about it has been particularly difficult, at least from my end :wink:, just some small discrepancies in measurement and the inherent time lag of this form of communication.Sorry to put you through all this.
Never expected it to be this difficult
That would reduce the resistance to 1.15Ω which will allow too much current to flow to the LEDs, but what do you expect to happen?I put the original 1.5Ω back in original spot as well as connecting 2-10 ohm resistors in parallel for an output on the LED's @ 3.1 Volts. I was hoping for 3.2 Volts.
Can you check the resistor that you thought was 188 and see if it's actually 153? Those pictures don't show any of the resistors since they're on the other side of the boards.
I went to my local Harbor Freight store and got one of those Ningbo lights just like yours so I can test anything that seems weird. I had been thinking of doing a similar conversion when you started your project which is part of the reason I took an interest.
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