DIY Solar Bottle Lamp

Solar Bottle Lamp is a solar-powered light that is constructed from waste plastic bottles. The design idea is to reuse waste plastic bottles

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Plastic accounts for 85% of marine litter and warns that by 2040, volumes of plastic pollution flowing into marine areas will nearly triple, adding 23-37 million metric tons of plastic waste into the ocean per year. This means about 50kg of plastic per meter of coastline worldwide.

The consequences of the above problem are:
1. Plastic pollution threatens food safety and quality, human health, and coastal tourism, and contributes to climate change.
2. Marine species ingest or are entangled in plastic debris, which causes severe injuries and death.
The main goal of this project is to reuse the tons of plastic bottles that are thrown into the garbage.

The core concept of the DIY Solar Bottle Lamp has two missions:

1. To prevent waste by repurposing and upcycling water and soft drink plastic bottles that are discarded and further contaminate the planet.

2. To make free solar-powered lights available to everyone.

I have designed this lamp by inspired from Moser bottle which was invented by Brazilian mechanic Alfredo Moser. The concept is that clear plastic beverage bottles filled with water and bleach can be fixed into the roof of an unlit building to refract sunlight around a room.

In 2011, Illac Diaz used Moser’s technology to start the Liter Of Light ( MyShelter Foundation), which used a grassroots model to provide lighting on a large scale. The program uses partners around the world to keep costs down, using recycled plastic bottles and locally sourced materials. The program also promotes local entrepreneurs, by providing financial incentives to locals who assemble and install the lights.

The Moser bottle lamp is simple and inexpensive but has a limitation. It only works during the daytime. So I have designed a solar bottle cap that can provide light during the night. By combining the Moser Bottle concept and my Solar Bottle Cap, a powerful lamp can be made.


  1. Reusing plastic bottles can significantly reduce pollution, greenhouse gas emissions, and energy usage.
  2. The use of the solar lamp will decrease the amount of local air pollution and saves energy.
  3. It can provide access to solar lamps at an affordable price to a wide range of people living in remote villages that are deprived of clean energy access.
  4. It also came out as an alternative business model with the potential to strengthen the overall rural economy by generating technology-based livelihood opportunities.

Working of Moser Bottle:

It works by the refraction of light rays because of different mediums, air, and water. By refracting light from the sun, it produces light 360 degrees around the room with an equivalent light power of 55 watts bulb. It will last for 5 years without maintenance and before the water has to be changed. The chlorine prevents the growth of microorganisms and maintains the clarity of the water.

If you want to know more about it, you may go through a nice research Journal. It is attached in the files section.

Image credit: -

How the Solar Lamp Works:

The solar panel receives sunlight from the sun and converts it into electrical energy. The controller board charges the battery during the daytime and drives the LED during the nighttime.

The solar lamp can be considered as a standalone Solar Photo Voltaic (SPV) system and contains four basic components:
1. Solar Panel: Convert Solar Energy to Electrical Energy

2. Controller: Charge the Battery ( Charger ) and drive the Load ( Driver )

3. Battery: Store the Electrical Energy

4. Load (LED): Provide the desired light output

How the Circuit Works?

The entire circuit is broadly dived into 3 parts:

1. Charger Circuit

2. Battery Protection Circuit

3. LED Driver Circuit

The power generated by the Solar Panel is extracted by the charger circuit and charges the battery. The protection circuit is responsible for providing various protections to the Li-Ion Battery. The LED driver circuit is responsible for driving the LED.

Charger Circuit:

The charger circuit charges the battery by taking power generated from the solar panel. It is based on a lithium-ion battery charger IC LP4060. It is a complete constant-current/constant-voltage linear charger for a single-cell lithium-ion battery. It uses only a few external components like resistors and capacitors. The circuit is based on the application circuit given in the datasheet.

 Battery Protection Circuit :

The Battery Protection Circuit provides various protections to the Li-Ion battery. The circuit is based on IC - AP6685 which contains internal power MOSFET, high-accuracy voltage detection circuits, and delay circuits. The IC has the following protections inbuilt:

1. Reverse polarity protection

2. Over Charge Protection

3. Over-Discharge Protection

4. Load short circuit protection

LED Driver Circuit :

... Read more »

STL Files for Enclosure _PCB V2.0.rar

RAR Archive - 1.88 MB - 10/21/2022 at 02:18


BOM for PCB V2.0.rar

RAR Archive - 21.36 kB - 10/21/2022 at 01:47


Gerber Files V2.0.rar

RAR Archive - 131.50 kB - 10/21/2022 at 01:30


Eagle Design Files V2.0.rar

RAR Archive - 387.96 kB - 10/21/2022 at 01:24


PCB Gerber

Gerber Files V1.0

x-zip-compressed - 120.46 kB - 05/02/2022 at 19:54


View all 6 files

  • 1 × Charger IC - LP4060B5F
  • 1 × Battery Protection IC - AP6685
  • 1 × Transistor - MMBT3904
  • 1 × MOSFET - AO3400A
  • 1 × SMD LED - 0.5W ( 2835 )

View all 14 components

  • Assembled the Enclosure

    Open Green Energy10/24/2022 at 02:00 0 comments

    After testing the Circuit, I have assembled the enclosure. The assembling process is as follows:

    1. Install the Solar panel on the top part of the enclosure.

    2. Install the LED PCB and seal it from the inside to prevent water ingress 

    3. Install the Button Switch Cap

    4. Install the PCB board and secure the 4 screws at the corners

    5. Install the 18650 Battery Pack

    6. Connect the LED, Battery, and Solar panel connectors to the PCB board. The labels are indicated on PCB with a polarity symbol.

    7, Align the top and bottom parts and close them by using two screws. Finally, install LED diffuser.

  • Tested the Circuit

    Open Green Energy10/24/2022 at 01:39 0 comments

    I have tested the circuit as per the above setup. The PCB is working as expected. I have also tested the backup time and the following are the actual results

    1. Mode-1: LOW Brightness -  26 Hrs

    2. Mode-2: MEDIUM Brightness -  12 Hrs

    3. Mode-1: HIGH Brightness -  7 Hrs

  • Assembled the PCB

    Open Green Energy10/24/2022 at 01:37 0 comments

    Arranged the SMD components as per the schematic diagram, so that it will be easier for placing the components on the PCB.

    First I have applied the solder paste by using a solder paste syringe.

    Placed the components by using tweezers

    Cooked the PCB using my Hot Plate.

    Soldered the Through Hole Components : 3 x JST connectors, Push Button Switch, and USB-C Socket

  • Enclosure Printed in SLA 3D Printer

    Open Green Energy09/25/2022 at 10:48 0 comments

    In my earlier project log, I shared the latest design for the Solar Bottle Lamp. Initially, I thought to print the design with my own 3D printer, but later I realized that I will never get a realistic commercial-grade product look if I print the parts with my own printer. Meanwhile, I got access to a nearby SLA printing shop and finally, I printed 3  prototypes.

    The outcome of the SLA printed parts is super smooth which is far better than my conventional FDM printer parts. I have printed the parts with white color material and then, spraypaint them with green and white color. You can see the final outcome of the different parts.

    Bottom Cover:

    Top Cover:

    Making Semi-Transparent Parts:

    The surface is sanded using fine sandpaper, then polished with a polishing compound. This results in the clearest surface possible but it is very time-consuming and only possible on surfaces that can be sanded easily. The LED diffuser needs a lot of sanding to get the semi-transparent look, you can see the below picture.


    Button Cap:

    Bulb Attachment: 

    This part is an optional part, I just printed it to check how it works with the original lamp design. I can say it looks far better than what I have expected earlier.

    Rubber Parts:

    In my designs, two parts are made of TPU, and I have struggled a lot to make these two parts. After a long time search, one vendor made it for me. But the outcome is not satisfactory. I think when I give mass order, maybe get good quality parts.

  • Solar Panel Arrived and Listed On Tindie Store

    Open Green Energy08/09/2022 at 10:35 0 comments

    I received my customized solar panel today. The quality of the solar panel is extremely good, you can see the actual pictures. The panel is rated for 0.55W / 5.5V and is suitable for outdoor charging of Li-ion/LiPo batteries.

    This panel is much more efficient, Quality assured, and Reliable than the commonly available Solar Panels on the market today. The efficiency of cheap solar panels available in the market is in the range of 14-17%  whereas this solar panel is assured to give more than 21% as it uses high-efficiency solar cells from Sunpower.

    I have listed the solar panel on the Tindie store, so anyone can buy it now. You can use this panel for any of your DIY projects which are powered by a single-cell lithium-ion / LiPo battery.

    Tindie Link:


  • Enclosure Design Upgraded

    Open Green Energy07/21/2022 at 09:42 0 comments

    In my previous log, I have updated that I will use a 18650 battery instead of 14500 battery and SMD LED instead of a straw hat LED. Due to these changes, the old enclosure will no more work. So, I have redesigned the enclosure to accommodate the bigger battery and SMD LED. The new design also included an arrangement for hooking this lamp to a backpack during camping and trekking, so that the battery will charge continuously.

    Pictures for new Enclosure Design :

    Rendered Picture of Final Product :

  • PCB Updated to V2.0

    Open Green Energy07/14/2022 at 04:31 0 comments

    I have designed a new PCB as per the schematic V2.0. There are two different PCBs

    1. Main Board

    2. LED Board 

    Main PCB Board: 

    The main PCB includes all the circuits for charging the battery, LED driver, and battery protection. I have used all the SMD components with the 0805 packages ( except the LED current limiting resistors R7, R8, and R9 which are 1206 packages) so that they can easily be hand soldered. 

    LED PCB Board:

    The LED PCB board only uses the 0.5W SMD LED ( 2835 package ).

    Update 02.08.2022

     PCB Arrived : 

    I ordered the PCB from PCBWay, the PCB arrived within 7 days. The PCB quality is really awesome. 

    Following are the images of assembled PCB.

  • Selecting the Solar Panel

    Open Green Energy07/06/2022 at 17:48 0 comments

    The calculated Watt-hours required to drive the LED is 2.75 Wh, considering peak sun hour is 4.5 for most places in India, the solar panel size shall be as follows:

    Considering the Battery Efficiency 90%, the effective Wh required  = 2.75/ 0.9 = 3.05 Wh

    Sun Hours = 4.5 Hrs

    Solar Panel Wattage = 3.05/4.5 = 0.679 W

    So we need a solar panel larger than the above-calculated value ( 0.68 W ). The available area in my enclosure to place the solar panel is 60 x 60 mm2. The suitable voltage for the solar panel to charge the 3.7V battery is 5.5V. There are many 5.5V solar panels available in the market with this standard size, the typical wattage is in the range of 0.4 -0.45W. 

    Finally, I decided to use Sunpower solar cell to get the maximum possible wattage ( 0.55W)  within this limited area. Following are the specifications of the Sunpower Solar panel, that I am going to use in my final product.

    Sample Picture Of Sunpower Solar Cell:

    Solar Panel Layout:

    1. Top Side

    2. Back Side 

  • Schematic Updated

    Open Green Energy07/06/2022 at 17:01 0 comments

    In my earlier schematic (V1.0), the solar panel is the only source to charge the battery. However, due to the limited area of the lamp, the solar panel mounted on the lamp is not sufficient to charge the larger capacity battery. So I have added a USB port (Type-C) to charge the battery faster. You can use an external solar panel or any USB source to charge the battery. It is also useful for sunny days when the panel doesn't receive sufficient solar radiation.

    New Schematic:

    Details of USB-C Port :

    I am using the vertical mount USB port as shown in the below picture. The dimensions are D=10.0, E=5.0, and F=7.90.

    The pinouts are  as tabulated below:


  • Updating to New Switch

    Open Green Energy07/01/2022 at 05:28 0 comments

     I am going to use a 5-pin switch with has 4 modes of operations as shown in the above image. By using this switch I will be able to operate the LED in the following modes:

    Mode-1: ON - High Intensity

    Mode-2: ON - Medium Intensity

    Mode-3: ON - Low Intensity

    Mode-4: OFF - Turn Off the LED

    Earlier I have used a 3-pin button switch for 3 different modes of operation as given below. 

    Mode-1: ON - High Intensity

    Mode-2: ON - Low Intensity

    Mode-3: OFF - Turn Off the LED

View all 18 project logs

  • 1
    PCB Assembly

    It's very important to first clean the PCB with some isopropyl alcohol. Then apply solder paste on the pads by using a solder paste syringe. Place parts with tweezers making sure that LEDs, chips, etc. are properly aligned. I like having a second board with no paste on it to see the alignment dots.

    Now you have many options to cook the PCB like hot air soldering gun, Hot plate, reflow oven etc. I have used my Miniware MH30 hot plate to solder the PCB. Set the temperature according to your solder paste melting point and place the PCB on the hot plate.

    It is important to look at the reflow profiles of all your components, to see how long you can heat your components for, and at what temperature. I usually just "wing it", and heat them at about 250C, for about a minute. You will see the solder melting, and the components being soldered into their respective places. Now you can turn off the hot plate and let it cool down completely.

    Once you have completed the soldering process it is important to remove the flux from PCB. Spray a small quantity of IPA (Isopropyl alcohol) Solution and clean it with the cotton.

    Now the PCB boards are ready to use.

    If you are not interested to assemble the PCB on your own, you may order the fully assembled PCB from the PCBWay store.

  • 2
    3D Printing

    I have used my Creality CR-10 Mini printer and 1.75 mm PTEG filaments to print the parts. I have printed it in 3 different colors yellow, Orange and Cyan. The diffuser is printed in the transparent filament. You need a support structure for printing the main body and top cover.

    My settings are:

    1. Print Speed: 60 mm/s

    2. Layer Height: 0.2mm

    3. Fill Density: 25%

    4. Extruder Temperature: 235 deg C

    5. Bed Temp: 75 deg C

  • 3
    Remove the Support From the 3D Printed Parts

    Both the top and bottom parts are printed with support structure, so we have to remove them before final use.

    Removing support from the main bodies is quite easy, just squeeze them with fingers, and they will be easily separated from the main body.

    Removing the support from the cap threaded area may need a screwdriver or any sharp object. After removing the support, you have to smooth out the cap threaded area. You can easily do it by twisting and untwisting a few times with a soft drinks bottle.

View all 11 instructions

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