GE865 RTC backup

3 thoughts on “GE865 RTC backup

  1. Hi Cosmin


    Can I put a battery on GE865 pin H2, VRTC? Is the "Telit_RTC_Backup_r2"  AN also valid for GE865?


    Furthermore, does the voltage on VRTC pin save also RAM contents, if the main power is switched off? Especially, if I have some data saved as a Python variable, will the contents be retained if there is a power-off period in between?


    BR, Tom

    1. Hi Tom, the theory and principles are the same and apply to newer
      modules; here is below some observation from my colleagues regarding RTC
      on these new modules:


      There are difference and note to make on RTC pin that is different from LITE.

      1) RTC pin has a current consumption higher than LITE (about 10uA, to be better measured)

      2) the main problem can comes from the high current if RTC battery is connected without Vbatt when module comes direct from
      before his first use. This current is as high as 0,5 mA and if somebody
      solder the primary battery and leave the board for
      many days before use it the battery get discharged. The solution can be:

        2.1) After mounted all the component turn on the module at least one time so SW start and programs the RTC.
               After this all is fine and module can be left without battery.
        2.2) Use a rechargeable battery (supercap) instead of Primary batt; this means no regulator is needed.
        2.3) No mount the primary battery when module stored in warehouse.

      3) The resistor depicted on Elite VRTC App. Note, 10KOhm, is too big. A 1 or 2K is enough.


      I do not think the Ram is saved to preserve Python state, the
      scripting engine shuts off at power down and starts fresh at each power