Lithium powered waterproof RGB LED lights
In this article I describe a way to replace AAA batteries in waterproof RGB LED lights.
Advantages: quite simple and cheap, no need to buy batteries anymore, rechargeable with any micro-USB (smartphone) charger
Disclaimer: by doing this modification you will void your warranty and there is a chance of destroying the lights, do it at your own risks.
This project started with the need of putting some lights in my shower. Obviously, anything plugged into the wall was immediately dismissed. After some research, I settle on this pack of 4 waterproof RGB LED lights (see picture above, available under many brands). They are not that bright but with 4 of them it is enough for my purpose.
This lights are powered by 3 AAA batteries, and while LED are pretty efficient, having 10 of them still means that you will have to change the battery multiple time per year, depending on your usage. Needless to say that having to change 12 batteries not only becomes expensive quickly but also quite wasteful and not eco-friendly.
This is the reason why I decided to make a little experiment by replacing the AAA batteries with a single cell lithium battery. The voltage is not exactly the same, but close enough (fully charged single cell lithium battery are around 4.2V), but lithium battery can output a lot more amps, and TBH it feels like the lights are brighter after the modification.
Tools and materials
- Soldering iron
- Third hand
- Small philips head screwdriver
- Waterproof RGB LED light x 4 (Amazon link or similar)
- Drone lithium battery x 4 (Amazon link or similar, max. size 26 x 44 x 9 mm)
- USB lithium battery charger x 4 (Amazon link or similar)
- Small electric wires
- Double-sided tape
Steps (for one light)
- Remove the lid to access the battery on the RGB lights
- Remove the AAA batteries if present
- Remove the three screws attaching the PCB to the plastic housing.
Removing the battery holders, this is the most tedious task as the holders are soldered to the PCB in multiple points:
- Secure the PCB in your third hand
- With your soldering iron, heat up the tabs holding one of the battery holder to the PCB
- With the pliers pull the battery holder until the tab comes out of the PCB
- Repeat 2 and 3 until all battery holders are removed
Light PCB wiring:
- Solder a short red wire (5-10cm) to the hole marked Vdd
- Solder a short black wire (5-10cm) to the hole marked Vss
Battery charger wiring:
- Solder the red wire to the hole marked OUT+
- Solder the black wire to the hole marked OUT-
- Remove the plug that comes with the battery
- Solder the battery's red wire to the battery charger hole marked B+
- Solder the battery's black wire to the battery charger hole marked B-
- Using the double-sided tape attach the battery to the the light's PCB, roughly in the center
- It is better not to attach the battery charger board to make it easier to plug it for charge later
- Using the 3 small philips head screws attach the light PCB to the plastic housing (as originally)
- You should now close the lid, making sure the rubber o-ring is correctly in place for a good seal against water
- To check if the battery charger is working, plug it to a USB charger a red light should appear
- Once charged the light turns blue
- Using the remote control you get in pack with the lights, push the On button first then the others to see if everything works as intended
If it was not for the removing of the battery holders this project would quick and easy, still it remains a fairly easy project to tackle for most beginners.
Note: I'm pretty sure this technique can apply to many electronic which uses 3 AAA or AA batteries.
Written by Olivier on Tuesday July 23, 2019