I have a project and i want to make it rechargeable my project contain Arduino pro mini and a 3.7v bat and this little thing in the picure
so how to connect these together..?!!!!
As it is, it will charge at 1A. I don't know if that is safe for your particular battery.
The resistor marked "122" (1200ohms) is the charge 'programming' resistor --
(1.2V / R) * 1000
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As in reply #2, but keep in mind that it does not allow for load sharing. Either charge the battery or use the battery to power the board, But not at the same time. Doing that can cause the unit to keep charging once the battery is already full, which in turn may cause it to explode. That is also the same risk when charging a battery to fast. Charging most LIPO's maximum current is about double of the capacity per hour (though i tend to go for just a full charge in an hour) So charging a 500mAH Battery with a 1A is fine. Anything smaller, and you should really change the prog resistor.
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To answer your original question, BAT+ on the module would be connected to the battery's positive terminal and, through an on/off switch, to the Pro Mini's Vcc pin. That's assuming your Pro Mini is an 8MHz version, and you are powering it directly from the battery. BAT- on the module would be connected to the negative battery terminal and to the Pro Mini's GND pin. Whatever 5V source you are using to provide charging current would plug into the USB connector on the module.
If your Pro Mini is a 5V 16MHz version, it would be connected the same way, but might not work. The datasheet says 16MHz needs a higher voltage than a single lithium battery. However, a lot of people ignore that, and it still works.
If your Pro Mini spends a good bit of time in deep sleep, you might be able to safely charge the battery and power the Pro Mini at the same time without adding a load sharing circuit. You would just have to be sure that the red charging LED turns off at some point, which indicates that charging has terminated even with the project load present. If it never turns off, you're in trouble.
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Again i want to add something, that is that the TP4056 does protect the battery from extreme discharge, but not against anything else. An FS312f-G in combination with 8205 mosfets will do a better job.
There is the option of upping the voltage using a MT3608 and a few other components.
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Yes, that module has no protection. So he would have to use a protected battery with it. But of course there is another version of the module which includes protection which he could use instead with an unprotected battery.
On the subject of load sharing, I still do not see cheap TP4056 charging modules from the Far East which include load sharing (aka "power path"). I think there are relatively expensive modules from Adafruit and Sparkfun that include it, but it's not clear why the usual Chinese sources don't produce them. I guess people usually just ignore the potential problems. Great Scott, for one. So maybe there wouldn't be a market for them.
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