DS3231 CR2032 Battery Problem and Solution

@ETE Teacher talked about the CR2032 Battery problem of the DS3231 Module in the forum, and the DS3231 module is used in the “Arduino PT2314 LCD, Spectrum Analyzer, Remote Control, Encoder” project, I used a CR2032 battery for the module, but when we use this battery, the battery life is between 1….3 years, normally the CR2032 battery It should take up to 10 years. The problem is that the DS3231 module has an internal charging section, many vendors did not mention this detail, I did not know about it. But the price of LIR2032 is quite high. CR2032 lasts for 10 years.

DS3231 Module Diagram

ETE Teacher’s explanation;

etepic.com/index.php/topic,4961.msg46028/topicseen.html

I have been using this card in my watch projects for a long time. The main reason for this is that the DS3231 IC has an internal oscillator called TXO. Let me tell you for those who don’t know what TXO is. Temperature compensated oscillator.

Let’s say the biggest enemy or problem of crystal oscillators is temperature changes. RTCs like the DS1307 or DS1302 we used before work with a crystal oscillator. Since these oscillators produce different frequencies in hot and cold, this causes this clock to stay forward or backward in many clocks that are exposed to hot cold change. On the DS3231, however, this problem is greatly minimized, and this RTC keeps time accurately for a very long time.

I started to have a CR2032 battery problem in the watches I made (and used) for a few days. As you know, CR2032 battery is installed on the RTC module and these batteries are expected to work normally for at least 7-8 years or even 10 years, but the batteries started to deteriorate before 3 years.

How do I understand this? When the electricity goes out, they lose the clock, I can understand it from there. When I took the batteries out, I saw that the batteries were a little swollen. I measure the voltage of the battery, which is normally 3V, it shows a value like 3.8V.

Anyway, the problem was caused by the 200 ohm resistor and the 1N4148 diode in series on the module, assuming that a charged battery will be inserted into the module. As you can see, this resistor diode duo charges or tries to charge the battery you installed with approximately 4.2V, and after a while that non-charged battery starts to swell and deteriorate.

So what should you do? ? If you do not use a rechargeable battery (LIR2032) on the RTC and use CR2032, you definitely need to remove the 200 ohm resistor. Otherwise, that CR2032 battery will deteriorate in a shorter time than its normal life.