For a project I'm looking for a charging solution to charge a LiPo battery, while at the same time being able to power a microcontroller with 3.3 V.
For that purpose, I bought a few TP4056 boards that also include a DW01A and a FS8205A and should be able to provide charging and protection.
The schematic of this circuit is:
I've been experimenting with these 2 batteries:
One is a 3.7 V, 1200 mAh battery, the other is a CN18650 9800 mAh battery (or at least, that's what is printed on them).
Charging them seems to work fine, after a while the green LED on the TP4056 lights up, indicating that charging is done.
At full charge, both batteries give just over 4 V. Since my microcontroller requires 3.3v, I used a XC6203P332PR (datasheet) to regulate the voltage. I hooked the Vin up to the OUT+ of the TP4056 circuit, Vss (ground) to OUT-.
I expected OUT+ and OUT- to give the same voltage as the B+ and B-, but unfortunately, it doesn't. With the 1200 mAh, I only get about 0.7 V on OUT+ and OUT-, with the 9800 mAh, I see erratic behavior, sometimes it gives the proper output voltage, but a lot of times, I only get 0.7 V out of it.
I can't quite figure out what's going wrong. I've tried multiple TP4056 boards and multiple batteries, but did not get a consistent figure. Googling around, I find mixed information about the TP4056, apparently there are also cloned versions of this chip around.
I was wondering if anyone knows the cause of my problem, am I doing something obviously wrong, or is the TP4056 just not the right way to go? And if not, are there any other suitable (and preferably affordable) solutions around?
