Portable Solar Lighting System or Battery Charger

I first made this sollar light last summer when we had problems with electricity in our cabin (tree fall on the power line and we didn't have any light source when we wanted to stay there overnight)

it works very well and when my friend saw it he asks me if I can make him something similar for camping

so I decided to make PCB because it has problems with overheating and soldering components together just with wires was a too long process

it is made out of three LiIon battery chargers for three 18650 batteries (you can use any Li-ion battery)

each battery have its own charger with protection circuits and if solderable jumpers are not soldered you can use each battery separately

when you connect one of these jumpers they will connect battery to battery out terminal and to the step-up converter if you add switch or jumper to switch terminal

out terminals from step-up converter are marked as 5V out because I using USB lights from eBay

but you can also use it for whatever you want just set different voltage

main components for PCB:

1. PCB ready to order link to PCBway just click and order 10 boards only for $5

if you are a new customer you can get 5$ discount link just register and get your discount

or download my gerber files

2. charger module ebay link (one with three chips as on my photo)

3. step-up converter with XL6009 chip ebay link buy same as on my picture I had a very similar one but the chip was fake, it doesn't work very well and it also didn't fit on my PCB

4. thermal pad or compound for charger modules is better compound, step up has pins on the bottom from trimmer so you need to cut them and thermal pad could help to isolate it from touching the ground on PCB

5. battery holders and batteries

holders must be separated, one for three batteries doesn't fit

other componnents:

1. enclosure box

2. connectors male, female

3. wires

4. switch

5. lights link I used colorful ones which were marked as 5 and 7W

but 7W was actually around 5W

6. solar panel 20W or more (if is above 6V you need step down converter)

tools:

1. soldering iron and solder wire

2. plyers

3. drimmel (optional)

4. drill press or drill

1. cut piece of cooling (heat conductive) pad or add thermal compound under charging circuit

and solder it to PCB board using some wire in holes for better strength and conductivity

when you using thermal pad apply a little bit of pressure when you soldering first two contacts for better thermal conductivity

2. step up converter has pins from the bottom site which could cause a short circuit when they scratch through soldermask so is better to cut or sand them as flat as it possible if you using thermal compound add a piece of plastic or electrical tape under cutted pins for better isolation

and solder it to the board using wires as in the first step

3. battery holders are not necessary you can use different types of LiIon battery than 18650

but if you decided to use 18650 batteries you can solder three holders on the backside of PCB or more batteries connected parallel to each charger but keep in mind one charger is set to 1A of charging current so charging will take longer

4. measure everything for possible short circuit and if is everything OK add a blob of solder to solderable joints under each charging circuit if you don't want to use one or more batteries separately

you can also add some extra components as you can see on the last photo

I used ordinary wall junction box, originally I wanted my box to be waterproof but one which used had bad design and water was leaking through screw holes other which I bought for the first prototype was better but after few months outside plastics start decomposing and it had a very weird smell and rough finish so it is no longer good as a portable box (it is just on surface it is common with these boxes it will last few years) this new box which I used in this instructable is made from different plastic so I will see if it will decompose same way or not

but now back to work:

if you have all components you can decide exactly where you want them always is better to make some sketches and template on paper

then you can punch holes with marking pin and start drilling first with smaller than with larger drill

when you using additional components use a small file to finish holes for needed dimensions

if you have all necessary holes you can put all components in and start wiring

when you have everything wired check correct polarity and connections with a multimeter

if is everything ok add batteries and test if it works

click for more images they contain little notes

you can use it for cabin gazebo.... for that you can use classic glass solar panels

if you plan to use it as a portable light source for camping, fishing..... is better to use flexible solar panels

when your solar panel have more than 6.6V you should use step down converter set for 5V close to charging connector

for example 12V 20W panel should be enough

if you don't plan to use it for some time you should discharge batteries to 3.7V to prevent capacity loses

and remove them from holders if is possible

feel free to ask any questions

when you make it you can send me a photo :)