Displaying min/max on Blynk BUT with esp.sleep?

Need Help With My Project
1

so i was using this code to send minimum reading on Blynk:

if (tempMin <= temp)
  {
    tempMin = tempMin;
    Blynk.virtualWrite(V5, tempMin);
  }
else if (tempMin > temp)
  {
    tempMin = temp;
    Blynk.virtualWrite(V5, tempMin);
  }

BUT now i added esp.sleep, it runs the code every time, so it thinks the temp is brand new every sleep cycle.

can i use EEPROM like i have hacked from @chrome1000 HVAC code:

 #include <EEPROM.h>
float temp, tempMin, newTemp;
void runBME280()
{
 bme.ReadData(temp);   //reads BME280 temperature
>>etc

  newTemp = temp;

  if (tempMin <= newTemp)
  {
    tempMin = tempMin; 
    Blynk.virtualWrite(V5, tempMin);
  }
  else if (tempMin > newTemp)
  {
    tempMin = newTemp;
    EEPROM.write(0, tempMin);
    EEPROM.commit();
    Serial.print("New minimum temperature saved to EEPROM: ");
    Blynk.virtualWrite(V5, tempMin);
  }

etc

void setup()
{
>>etc etc
   EEPROM.begin(20);  //Get saved temperature minimum from EEPROM
   tempMin = EEPROM.read(0);
}

in the EEPROM.begin() how do i determine how many bytes i need for the tempMin float? the code i hacked is not really easy to work this out?

and is the address of (0) OK to use for this?

(it complies OK, but it is cold and dark and late at night and i don’t want to go out to get the hardware)

2

@Dave1829 EEPROM address 0 is fine on the ESP.

EEPROM holds 4 bit, bytes in a maximum of 512 locations (0 to 511).

1 address EEPROM.begin(4);
2 addresses EEPROM.begin(8);
etc

Each memory address can therefore store the number 0 to 255.

You will have to do some fancy float to byte conversion before the write and vice versa for the read.