An apparatus comprising: a logging system configured to be permanently installed at a wellbore downhole location, the logging system comprising: a logging instrument including a rechargeable energy storage and electronics, and a cable configured to charge the rechargeable energy storage from a remote power source; wherein the rechargeable energy storage is a high temperature rechargeable energy storage comprising a rechargeable ultracapacitor, whereby the ultracapacitor and other power sources to provide power for the electronics are comprised in a power block of the logging instrument, and having an operating temperature range of 80°C to about 210°C with a volumetric leakage current normalized over the volume of the ultracapacitor of less than 1 amp per litre within the entire operating voltage and temperature range, whereby a maximum rated operating voltage of the ultracapacitor is about 4 volts at room temperature and adjusted down to a maximum rated operating voltage of about 0.5 volts at 210°C, wherein the rechargeable energy storage is configured to be trickle charged from the remote power source for periods of a first duration at a first power level until enough energy has been accumulated for a normal operation of the logging instrument, and to provide power to the electronics for the normal operation of the logging instrument for periods of a second duration at a second power level, wherein the first duration is longer than the second duration and the first power level is less than the second power level, and wherein the logging instrument and the electronics are coupled to topside equipment of the apparatus via a communications channel for providing communication to the topside equipment, which communication channel is configured to be operated via electromagnetic telemetry. a logging instrument including a rechargeable energy storage and electronics, and a cable configured to charge the rechargeable energy storage from a remote power source; wherein the rechargeable energy storage is a high temperature rechargeable energy storage comprising a rechargeable ultracapacitor, whereby the ultracapacitor and other power sources to provide power for the electronics are comprised in a power block of the logging instrument, and having an operating temperature range of 80°C to about 210°C with a volumetric leakage current normalized over the volume of the ultracapacitor of less than 1 amp per litre within the entire operating voltage and temperature range, whereby a maximum rated operating voltage of the ultracapacitor is about 4 volts at room temperature and adjusted down to a maximum rated operating voltage of about 0.5 volts at 210°C, wherein the rechargeable energy storage is configured to be trickle charged from the remote power source for periods of a first duration at a first power level until enough energy has been accumulated for a normal operation of the logging instrument, and to provide power to the electronics for the normal operation of the logging instrument for periods of a second duration at a second power level, wherein the first duration is longer than the second duration and the first power level is less than the second power level, and wherein the logging instrument and the electronics are coupled to topside equipment of the apparatus via a communications channel for providing communication to the topside equipment, which communication channel is configured to be operated via electromagnetic telemetry.