Converting LED Fairy Lights from AA Battery to USB - Mini Project

Here’s how I converted some LED holiday twinkle lights from running off 3 AA cells (4.5v) to running off USB (5v).
Check out my other electronics videos here: • Electronics

[@emilyrln]

This is super useful! I'm getting tired of swapping and recharging batteries for all my Christmas decorations 😂 and I want to convert the ones that run on coin cells to something renewable (probably one AAA or AA for size).

[@triplebacon1]

why not use resistors of the correct value if you are dropping the load ?

[@Casey_Schmidt]

The answer is simple, ‘the best tool for the job is the one you already have’.

[@triplebacon1]

@@Casey_Schmidt true! and this works quite adequately 😃

[@jserrambana]

I have an led light strip currently powered by re-chargeable batteries like the ones inside of remote cars … I tried to put a usb plug ref to red black to black … Idid not have a diode would that have been the reason it did not turn on when I plugged in to my battery pack

[@jserrambana]

Also would I need a that soldering tool or would electrical tape work any help is greatly appreciated

[@Casey_Schmidt]

The purpose of the diode is only to drop the voltage down. In your case, the 5 volt USB supply may not be high enough depending on how many cells were in battery. Check the voltage of the cells when they are fully charged and set your input voltage at or slightly below that level. You may need a 9V power supply. I highly recommend getting a soldiering iron. It makes life so much easier when doing any related to electronics.

[@type670]

So the diode is meant to drop the voltage. Do I risk bricking my led string light if I use a 5 volt usb on a set that uses 3 AA batteries? Thanks!

[@Casey_Schmidt]

It will likely be fine but the LED’s will Be brighter and won’t last as long. You’ll have to decide for yourself if you’d like to try.

[@type670]

@@Casey_Schmidt well thanks to you I know what diodes are used for. Thanks so much for sharing your knowledge! ☺️

[@siscraftshop9612]

why after installing the diode, the voltage was not measured again using a voltage meter, I became curious🥲 because I've tried converting the 3x lr44 battery to usb like in the video, on the wire lights, the circuit burns out after a few seconds😂 I will try using a 1n4007 diode, thanks for the video👍🏻👍🏻👍🏻

[@Casey_Schmidt]

I did all my checks before hand if I remember correctly. I maybe glossed over that part in the video. You can use more diodes in series to drop the voltage further or use a zener diode.

[@siscraftshop9612]

@@Casey_Schmidt is the voltage reached around 4.5 V after using 2 diodes? like 3x AA batteries? . one more question because I'm very newbie about this😅 if it is turned on for a long time or all day does it not heat up the diode or the electric box? does the stable voltage keep the lamp last a long time without burning out? . Thank you for responding to noob's question 😁

[@Casey_Schmidt]

@@siscraftshop9612 If the enclosure that the diodes are in is a reasonable size, they should be fine. I've run mine for many hours with no issues. The fun part about electronics is that they sometimes blow up. I also don't mean to imply that the way I did my modification is the best way, it was just a cheap/easy way for me to do it. Good luck and have fun with electronics!

[@type670]

@@Casey_Schmidt me again :D. you mentioned a zener diode that are two directional vs a regular diode that are one directional; does this mean I don't need to be concerned about the polarity with a zener as I would with a regular diode? thanks!

[@Casey_Schmidt]

@@type670 the direction is very important. A zener diode has a voltage threshold when put in “backwards”. I suggest reading up on them before using them.

[@kiddadd]

Can you melt wire to use as sodder

[@Casey_Schmidt]

Not that I know of.

[@jonieevangelista]

what's the value of those 2 diode?

[@Casey_Schmidt]

I do think diodes have a value per se. At least not like resistors or capacitors. They are 1N4007 diodes, the ubiquitous small THT diode. I think they drop something like 0.7V each?

[@jonieevangelista]

@@Casey_Schmidt really appreciate! thank you so much!