DIY - Solar Battery Charger

Hi everyone, I'm back again with this new video tutorial. In this tutorial I'm gonna show you how to charge a lithium 18650 cell using TP4056 chip, utilizing the solar energy or simply the sun. Wouldn't it be really cool if you can charge your mobile phone batteries using the sun instead of a USB charger? You can use this as a DIY portable power bank. The total cost of this project excluding the battery is just under $5. The battery will add up another 4 to 5 bucks on top. So the total cost would be like $10. All components are available on my website for sale for really good price. For this project we need a 5 volt solar cell, a general purpose circuit board, a 1N4007 high voltage high current rated diode, a copper wire, two PCB screw terminal blocks, a 18650 battery holder, a 3.7 volt 18650 battery, a TP4056 battery protection board with or without a protection IC, a 5 volt power booster, some connecting cables, and general soldering equipments. Looking at the board we can see it has the TP4056 chip along with few other components of our interest. There are two on-board LEDs, one red and one blue. The red one comes on when it's charging and the blue one comes on when the charging is done. Then there is this mini USB connector to charge the battery from an external USB charger. There are also these two points where you can solder your own charging unit. These points are marked as IN- and IN+. The battery will be connected to these two points marked as BAT-plus and BAT-minus. Pretty self-explanatory. The board requires an input voltage of 4.5 volt to 5.5 to charge the battery. There are two versions of this board available in the market. One with the battery discharge protection module and one without it. Both boards offer one ampere charging current and they cut off when it's finished. Furthermore the one with protection switches the load off when the battery voltage drops below 2.4 volt. This protects the cell from running too low and also protects against over voltage and reverse polarity. These boards generally get really hot so I'll be soldering them a bit above the circuit board. To achieve this I am going to use a hard copper wire to make legs of this actual circuit board. I will then be sliding the unit on the leg and will solder them all together. I will put four copper wires to make four legs of this circuit board. You can also use male breakable pin headers instead of the copper wire to achieve this. This assembly is very simple. The solar cell is connected to the TP4056 battery charging boards IN-plus and IN-minus respectively. A diode is inserted at the positive end for the reverse voltage protection. Then the BAT-plus and the BAT-minus of the board is connected to the positive and negative end of the battery. That's all we need pretty much for this whole project. Now to power an Arduino board we need to boost up the output to 5 volts. So we are adding a 5 volt voltage booster to this circuit. Connect the negative end of the battery to the IN-minus of the booster and the positive to the IN-plus by adding a switch in between. Okay now let's have a look at what I've made. I have connected the booster board straight to the charger however I would recommend putting a switch in between. So when the device is charging the battery is not actually used. Solar cells are connected to the input of the lithium battery charger whose output is connected to the 18650 lithium battery. A 5 volt step-up voltage booster is also connected to the battery and is used to convert 3.7 volt DC to 5 volt DC. Charging voltage is typically around 4.2 volt. Voltage boosters input range from 0.9 to 5 volt. So it will see around 3.7 at its input when the battery is discharging and 4.2 when it's recharging. The output of the booster to the rest of the circuit will keep its value to 5 volts. So now we are out in the sun to test our project. You can see the charging light on the TP4056 board is on and the activity light on the booster board is also on. Let's plug in our load and see if the circuit is able to power it or not. We can see that the LED torch is lit but it's very dim. Now let's plug in the battery and see if the entire circuit works the way we want. That's it! Ta-da! Success! This project will be very helpful to power a remote data logger. As we know power supply is always a problem for a remote logger and most of the times there is no power outlet available. Situation like that forces you to use some battery to power your circuit but eventually the battery will die. Question is do you want to go there and recharge the battery? Our inexpensive solar charger project will be an excellent solution for this situation. This project can also solve efficiency issue of a drainer when in sleep. Sleep saves battery however the sensor and the power regulators will still be consuming battery in idle mode draining the battery. By charging the battery as we use we can solve our problem. Thanks again for watching this video. I hope it helps you. If you want to support me you can subscribe to my channel and watch my other videos. Thanks! See you again in my next video. Bye now!