I have several T-Display-S3 units and want to use them with small LiPo batteries that are rated at 350 mAH and 400 mAH.

Before using them I wanted to check to make sure that the Li-Ion charging circuit is setup properly and would not over charge the batteries. Namely, the battery manufacturer specifies that the batteries should not exceed a 1C charge rate. For example, if the battery is rated at 350 mAH then you should not exceed 350 mA, and for the 400 mAH battery the charge rate should not exceed 400 mA.

To check the T-Display-S3's charging circuit I looked at the schematic posted on GitHub and it shows that the charging circuit is controlled by U6 which is a TP4056 linear Li-Ion battery charger. The schematic also shows that a 2K ohm resister is used to program the charge rate. Using the TP4056 datasheet to calculate the charge rate it shows that if a 2K ohm resistor is used then the charge rate would be 580 mA which is too high for the batteries that I want to use.

Based on this I then looked into reprograming the charger for a lower rate by replacing the 2K ohm resistor with a 10K ohm resistor. Using a 10K ohm resistor would set the charge rate to 130 mA, which would be safe for the batteries. But when I try to find the TP4056 on the PCB it cannot be found? The datasheet shows that the IC should be a 8 pin SOP-8 package which cannot be located. Tracing out the PCB I find that the charging IC appears to be a device that is a 5-Lead TSOT-23 package with the marking of 65b311 printed on top. This does not agree with the posted schematic and I have the following questions and concerns?

1. Is it possible to get an updated schematic that shows the actual circuit for the T-Display-S3?

2. It would be good to provide instructions on how to replace the programing resistor (i.e. location of resistor and values for different charge rates). Providing the information would make the board more versatile and you would possibly sell more devices?

3. On the GitHub webpage it shows FAQ 10 "What battery to choose". The FAQ shows two examples, where 350 mAH and 400 mAH batteries are recommended. Based on the current schematic (TP4056 and 2K ohm resistor) the existing charge circuit would over charge the batteries. My research shows that using the existing circuit the battery capacity should not be lower than 580 mAH to be safely used. Please correct me if I am wrong or you may want to reevaluate the answer that is posted?

4. To make sure that the T-Display-S3 is safely used, it would be a good idea to post the minimum size battery and charge rate in your specifications and include them on you main webpage.

Thanks