Interfacing SD card and RTC to Wemos D1 mini

I have an interface problem that i hope someone can solve.
I am using a Wemos mini D1 and I wish to connect up a micro sd card and an RTC but the two seem to be incompatible. The RTC is a DS3231 and I have used the library by Makuna which is recommended and supposed to be compatible with the WEmos D1 mini.
Individually they both work fine, but not together. I have attached a code that first initialises the RTC and then after 10 seconds initialises the SD card.
to start with the date and time are correct but a soon as the SD card is opened the date is rubbish.
Any help would be appreciated. Thanks

#include <Wire.h>
#include "RTClib.h"
#include <SD.h>
#include <SPI.h>
RTC_DS3231 rtc;
int sec = 0;
char daysOfTheWeek[7][12] = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};

void openSD() {
Serial.println("Open SD card");
if (!SD.begin(4)) {
Serial.println("Open SD card failed");
Serial.println("SD card open");

void setup () {
#ifndef ESP8266
while (!Serial); // for Leonardo/Micro/Zero
delay(3000); // wait for console opening

if (! rtc.begin()) {
Serial.println("Couldn't find RTC");
while (1);

if (rtc.lostPower()) {
Serial.println("RTC lost power, lets set the time!");
// following line sets the RTC to the date & time this sketch was compiled
rtc.adjust(DateTime(F(DATE), F(TIME)));
// This line sets the RTC with an explicit date & time, for example to set
// January 21, 2014 at 3am you would call:
// rtc.adjust(DateTime(2014, 1, 21, 3, 0, 0));


void loop () {
DateTime now =;

Serial.print(now.year(), DEC);
Serial.print(now.month(), DEC);
Serial.print(, DEC);
Serial.print(" (");
Serial.print(") ");
Serial.print(now.hour(), DEC);
Serial.print(now.minute(), DEC);
Serial.print(now.second(), DEC);

if (sec == 10)


Your post was MOVED to its current location as it is more suitable.

alternative A) use TimeLib to keep time while running. only initialize it from the RTC at power-up or once a day (esp8266 has only software I2C)

alternative B) esp8266 has built in RTC which can be synchronized from NTP service so you don't need external RTC.

Hello, do yourself a favour and please read How to get the best out of this forum and modify your post accordingly (including code tags).