This is an old revision of the document!
| portable-led-bar | |
|---|---|
| Status | active |
| Founder | lepi |
| Source | lepi00/portable-led-bar |
DISCLAIMER: This is not yet a finished project intended as instructions but only a means to share progress on the project. \\ \\ This might be dangerous to attempt !!! \\ \\ If you attempt to follow any of this, you do it at your own risk.
Adapting a mains AC led bar to work with a battery of 18650s
by lepi(lepi at-a hackerspace.pl)
KiCAD files:
https://github.com/lepi00/portable-led-bar/tree/main/kiCAD-portable-led-bar
Revision 0.1
Intro
The purpose of this project is to adapt a 220AC UV LED-Bar to work with 18650 cells.
I have just started learning electronics, and my knowledge is very basic.
Specifications
The LED Bar - Light4Me LED UV 8
| Characteristic | Value | |
|---|---|---|
| Voltage: | AC110-240V, 50/60Hz | |
| Power: | 30W | |
| Light source: | 8x3W UV LED | |
| Light angle: | 65° | |
| Light wavelength: | 390-410 nm | |
| Dimensions: | 450 x 50 x 40 mm + 55 mm pins | |
| Weight: | 0,6 kg | |
| LED driver inside (IP65): | ||
| Model: | ZW0820 | |
| Power: | 27 W | |
| Input: | AC85V-265V 50/60Hz | |
| Output Voltage: | 27-36V DC | |
| Output Current: | 600 mA ±5% | |
| TA: | 60 °C | |
| TC: | 80 °C |
18650 Cells
| Characteristic | Value | |
|---|---|---|
| Datasheet: | (https://www.tme.eu/Document/e06617d885c58dfb3fecaf4abbe330c4/ICR18650-26H.pdf)[“datasheet”] | |
| TME Symbol: | Samsung ACCU-ICR18650-26H | |
| Rated voltage: | 3.63 V | |
| Capacity: | 2.6 Ah | |
| Maximum current: | 5.2 A | |
| Charging Method: | constant voltage, limited current | |
| Charging Voltage: | 4.2 V ±0.05 V | |
| Charging Current (standard): | 1300 mA | |
| Charging Current (max): | 2600 mA | |
| Diameter: | 18.4 mm | |
| Length: | 65 mm |
Battery charger - Tangspower TP-L8S20 Li-ion charger
| Characteristic | Value | |
|---|---|---|
| Maximum Voltage: | 8 * 4.20 V = 33,6 V | |
| Charging Current: | 2 A | Passive, PFC filter |
The Story
Revision 0.1
A friend of mine performs POI with POI-tails that are neon-yellow. The thing is made to shine in UV light.
Some AC mains LED bars I have, revealed a lot of space inside the casing profile - more than enough to house 8 18650 cells.
The LEDs have a “PowerLed” package soldered in-series upon a pcb with no other elements, but most likely have some resistor inside the package, as multimeter LED tester does not show anything when testing a single LED.
Remembering next-to-nothing about Electrical Circuits, I started designing a circuit, that would:
- Power the LEDs from cells
- Allow charging the cells without taking them out
- If possible leave the original charger with mains connection
First I considered two solutions: - LEDs and cells in parallel
- Operating current would be 0.6 A * 8 = 4.8 A
- Charging current would be 1.3 A * 8 = 10.4 A
- LEDs and cells in-series
- Operating voltage would have to be 26.9 V (3.36 V / LED)
- Charging voltage would have to be 8 * 4.2 V = 33.6 V
Parallel...
- I have a TP4056 03962A Lithium Battery Charger with protection module
- Initially I thought that would be crazy to put 8 of these inside
- Also wiring LEDs in parallel would if I understand correctly require to put at least 40 cm * 8 = 3.2 m of thick wire - that might be difficult.
In-series...
- A friend informed me to the fact, that I could use an external 33.6V charger which seemed to be easier.
- And also that I could use LM317 to regulate current out of the cells to LED's
- I decided to use a I/0/II switch and an IEC cord socket with the original LED driver if possible.
Emeryth suggested:
- to learn more about li-ion cells before I use un-protected or multiple cells
- to put some protection between cells and the cell charger
- to use a DC-DC converter instead of LM317 that produces too much heat
- to rethink if I need all LEDs in-series
Next Steps:
- Research Emeryth's suggestions
- Find a solution to connecting the cells
- decide whether to solder the cells (dangerous, potentially capacity hindering)
- contact weld the cells (I don't have access to a contact welder)
- design a 3d-printed casing for the cells with springs, that would slide into the LED bar casing
- remember to discharge cells before in case of soldering
Notes:
- https://pl.aliexpress.com/item/1000001962896.html
- https://lcamtuf.coredump.cx/electronics/