Convert: Solar LED Fairy Lights to USB power

Convert solar powered string LED lights to be USB powered, run brighter and last much longer per charge.

These lights are no longer suitable for use outdoors once converted unless you use a waterproof housing for the USB power source!

This is the second upload of this video, thanks to Martin Webster for highlighting an error in the first upload :-)

[thenightowl]

Finally I found this video that explains briefly about the needed resistor. I helps a lot. Thank you.

[OctiveKyla]

Love the Tech Bit. Keep going on being awesome!

[jonieevangelista]

sorry for the noob question, resistor is to avoid it from getting burned right? i have this type of led strip, 5 meter - 50 leds...i have soldered it directly to usb without resistor, some led got burned some are not...if i'm going to do what you did here, am i still gonna burn the other led? or this is actually the solution to my problem - i am going to remove the broken ones and solder them again with fine ones...thank you!

[isoguy.]

In the vid you said that we know V=5V, okay that's printed on my poundland power bank, given.
Then you went on to say:-
We know I=80mA but I don't have a bench power supply! What assumptions can I make for my white LEDds?
I would like to try this project on 50 LEDs so I really would like to know how to find "I" so that I can calculate the correct resistor for my LEDs.
Would an 1/8W or 1/4W etc. resistor be needed? And how would I calculate this for my 50 led string?
Sorry to be a pain but would appreciate the extra info.
Really useful vid and thanks for sharing this useful project.

[BarnOwlCat]

Hi Craig, thank you for such an informative and to the point video! I accidentally bought solar powered fairy lights from Ebay. Confusing listing where two of the three lengths was battery while the one I chose was solar. I do have a question, how do you know which string on your fairy lights are positive and negative? Thank you once again.

[dnbshaggy]

I've got several sets of these crappy solar lights, could I connect them all to a single USB? They all use very similar solar boxes with single AA batteries inside.

[peterthomson]

Craig, love these videos. I have a LED string light curtain with horrible combination mode nonsense. I just want to flick switch and they are steady on. Would this method work for this to bypass the need for always having to manually switch on?

[nilbject]

hey, can you redo this video with the solar chargers that take 3 batteries? replace the AA's with a lipo? add a esp32? inside the solar case to remain weatherproof?

[Alex-osco]

This is an excellent video explaining everything, thank you! When you say you bench tested the brightness you liked am I correct in saying there is no danger in applying a 5V 1amp USB charger to a string of xmas 200leds. They were powered by a 1.2V 400milliamps? Thanks!

[xdd]

What about a string of multi function lights....only every other bulb lights when converted to USB 5v?

[iimnana]

Really love how you show the calculation😍 but I didn’t get it where 8 mA comes from, so would you please explain that?😃

[imho]

Run 2 resistors together to get 94 ohms.