Methods, systems, and apparatuses are described for using a portable smart meter configured to connect an electric vehicle (EV) to an outlet at a service location associated with a service owner in order to charge or discharge a battery of the EV. The portable smart meter may be further configured to determine an amount of energy used to charge the battery of the EV, or the amount of energy discharged from the battery, via the outlet at the service location in order to bill an owner of the EV based on the amount of energy used to charge the battery instead of the service owner or credit the owner of the EV based on the amount of energy discharged from the battery.

A piece of equipment includes a housing in which there are incorporated an emitter emitting light signals, a receiver arranged to receive the light signals after they have been reflected against an inner wall of the housing, and a processing unit arranged to control the emitter so that it emits a detection light signal, oacquire a first electrical signal produced by the receiver when it receives the detection light signal, odetect, on the basis of a first level of the first electrical signal, whether the housing is open or closed.

A method for updating Subscriber Identity Module, SIM, information in a battery powered utility meter with an integrated modem for cellular communication. The modem is with intervals controlled to connect to a cellular network. When the modem is connected to the cellular network data is transmitted to a head end system. As a response the modem receives a first data message from the head end system via the cellular network. The modem is controlled to remain connected to the cellular network long enough to receive the response whereafter the modem enters Power Saving Mode or is powered off. The utility meter determines if the first data message comprises an indication that a Short Message Service message or a second data message containing Subscriber Identity Module update information is to be received by the modem via the cellular network during a second time period. If the first data message comprises said indication, the modem is controlled to enter RRC idle state and Discontinuous Reception mode or Extended Discontinuous Reception mode, during the second time period. Finally, the modem enter idle state and power saving mode or is powered off, at the end of the second time period.