How to replace SMD blue Led with conventional red LED?

[cap__]

"I heard that a blue LED has different voltage values than green and red ones. Green and red ones are easily replaceable, but how do I do that with the blue one?"

"I have to use the blue one, because green means fully charged and blue means charging."

[cap__]

"A major mistake by buck converter manufacturers: They always "always" forget the solder pads for your own LEDs."

[stj]

voltage is not important, your limiting the current.
so you may want to increase the resistor value a bit - or not, it depends how bright the leds are

[sam_sam_sam]

One thing I would add if you are going to use this type of component on a board that has surface mounted parts and you want to use through hole components you can but keep your components leads short as possible and use hot glue to keep them in place and not ripping the components traces from being torn off the board another option is to use very thin wire to the LED and still put some hot glue on the wires to keep them from falling off the board from vibration and breaking loose

[cap__]

Thanks,

Red smd led = 1,7v
Green smd led = 1,7v

Blue smd led = 2,5v

[stj]

thats not important - it's the mA required for the brightness you want out of them.

[CapLeaker]

Yeah, look up something like an NSI45020 or NSI45015. LED's are current controlled not voltage controlled.

[momaka]

Well, since you want to have a red LED in place of a blue LED, the answer is simple: you don't need to remove the blue LED at all. Just install the red (or green) LED in parallel to the blue LED. Since red and green LEDs have a lower voltage drop, they will begin to conduct way before the blue LED does. Thus, the blue LED should not light up at all (or it might just barely, but I doubt it would be too visible.)
In fact, I just helped a family friend's kid with an issue like this last week. He was doing a project for an intro Engineering class and couldn't understand why from the two LEDs he had installed in parallel, only the red one was lighting up properly. He had the proper current limiting resistor and all... but he didn't know that red and green LEDs had different voltage drops, hence why one would light up and the other wouldn't.

[cap__]

Is not that easy
The leds have a weird polarity.uPlus and minus are reversed on the second one.

[momaka]

Doesn't matter. I have a few red (or was it green[?], I forget now) LEDs like that, where the big "cathode" side seen inside through the LED lens is actually the Anode. I just flip those around and they work fine.
Or are you dealing with 3-terminal LED's here??