Is MeterStop value the total charged during 1 session or the total since the meter has been installed?

[RobbeVW]

The StopTransaction request holds a parameter called MeterStop.

In the documentation, it mentions the following:

  /**
   * This contains the meter value in Wh for the connector at end of the transaction.
   *
   * @return meter value in Wh.
   */
  public Integer getMeterStop() {
    return meterStop;
  }

Does this mean this parameter returns the meter value for the total Wh charged during that session or transaction. Or does this mean the total that has been charged since the meter was ever installed? Both OCPP documentations and this one are open for interpretation.

[rpseng]

It should be cumulative, the total Wh of a specific transaction should come from the difference between StopTransactionRequest.getMeterStop() and StartTransactionRequest.getMeterStart().

[robert-s-ubi]

OCPP allows both. There are charge points out there that reset the meter to 0 kWh on each reboot, others on each transaction, and yet others never. It depends on the type of meter you have.

[mmauksch]

Can also confirm that I can't find anything specific in the ocpp standard. Cann tell you from experience, that i've seen both variants (meter readings for the whole lifetime being used and start starting with 0 and ending with consumed energy) in the wild.

As the question seems to be answered I would close this :)