Help in Battery Connection

Hi
I am building a project with arduino which is based on solar supply
I am using 18650 battery with TP4056.
I am powering TP4056 with Solar Panel of 6V and charging the cell with TP4056 with the help of solar power.
But now the issue is I am stuck at one point only that how to charge and supply the power to arduino at the same time
can anyone pls help me with this?

Not sure if this will help you or not, but I have a solar garden light with motion sensor like this one:


I have a board similar to an Arduino Pro Mini 3.3V with an RFM69HCW radio module on it, and I simply power mine by connecting board 0V and Vin directly to the 18650 battery inside. It runs 24/7 and it's been running for over a year now without any visible issues.

However, I'm no expert so it could be luck rather than science that it works.

The solar panel powers the TP4056 which charges the 18650. You can add a DC to DC step up converter to 5 volts after 18650 and power the Arduino from that. There are combination boards with TP4056 and DC DC converter together like this https://www.aliexpress.com/item/32951247451.html.

I think you need to study lithium charging - to charge and use the cell at the same time is difficult as the load changes the voltage and makes any charge current wrong .
Lithiums are not charged just from a constant voltage .

There are some chips around that can handle this “Pass through charging “ , but difficult to use ( surface mount with critical Layout requirements)

Read me

You can do both at the same time if your load current is small enough. But even if that works, eventually the battery will be charged, and the TP4056 will shut down. That means the battery has to take over powering the circuit even though the sun may be shining brightly.

To charge the battery and power the load independently, you need what's called a load sharing circuit. If you were powering from USB, that circuit would consist of a P-channel mosfet, a schottky diode, and a resistor. But that won't work with solar power because the input power from the panel varies, and the mosfet will not switch on and off correctly.

If your load current is small, or you can put your project into deep sleep most of the time, you may be better off without the load sharing circuit, which would be more complicated for solar power.

One critical issue is what voltage you need for your project. If you need 5V, then you will need a boost converter to get the battery/charging voltage up to 5V, but if you include load sharing, panel voltage will be passed through, and a 6V panel could produce nearly 7V under bright sun, and then things become very complicated.

If you need 5V, the module referenced by Flashko might work well if you are using a protected battery. Your battery will cycle between 4.1V and 4.2V as the TP4056 turns off and on, but that might be acceptable. Just make sure that charging does eventually terminate. If your load current is too high, with no sleep periods, charging may never terminate, and that could be dangerous.

You could look at lead acid or NiMh as an easier option ?

Hi as per you all guide me I have purchased lead acid battery as well as solar panel and also someone told me to purchase TP4056 charging module so I have purchased it to.
Now the query is how to charge the lead acid battery through solar panel and also protect it was overcharging.

Hope you understand my query

Can anyone pls help me out

More solar panels in parallel with what you have for more current. You need your demand plus the .1C charge current for output frpom, the solar cells.

Got it but what's about Overcharging Protection

The TP4056 is for lithium batteries, not lead acid.

Thanks for your information but my query is still not resolved

From this I get that I can charge the battery through 1 6V Solar pannel.

But now the main issue is what's about overcharging protection when you are saying

So How can I protect it from overcharging

I can't give you a complete answer as I have no experience charging lead acid batteries with a solar panel. Lead acid batteries are simple to charge, you just need to apply between 2.2 and 2.3V per cell, so for a '6 volt' lead acid battery, which has 3 cells, you need between 6.6 and 6.9V. If you do this you don't need to worry about overcharging, the battery will take care of itself. To be clear, all you need to control is the voltage.

Now you will ask what you use for this, this is where my answer is incomplete. If you were using mains power all you would needs is a power supply with the output adjusted in the range 6.6 to 6.9V. I don't know if it's that simple with a solar panel, never tried. You could try a buck / boost converter set to 6.75V and see what happens, or you can wait for someone to give you a better answer.

Thanks

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