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Portable Energy Usage Monitoring

Portable Energy Usage Monitoring

Quick Overview

The Tinytag Energy Logger is the perfect solution to monitor voltage and current which can be used for spot checks or longer term logging. The unit will also determine power and power factor, plus peak and average values can be recorded. Voltage is measured via the standard mains lead and current is measured using non-invasive flexible coils. The kit contains everything needed to start logging, including 3 Rogowski coils, UK and EU mains leads, a USB cable and Tinytag Explorer software. Two kits are available, one with 3 standard size clip on Rogowski coils (85mm diameter) and a second with 3 large clip on Rogowski coils (175mm diameter).


The Tinytag Energy Logger can be used to monitor single and three phase energy supplies. It combines the level of performance required by experts with the level of simplicity required by those that are new to energy management.

The unit is ideal for monitoring building energy supply, sections within a building or individual pieces of equipment. Data from the Tinytag Energy Logger can be used to identify power hungry or inefficient equipment and peak load times, and can highlight equipment that is left powered up or idling unnecessarily. The Tinytag Energy Logger provides visibility of energy usage so that effective measures can be taken to reduce electricity bills, lower carbon footprint and improve environmental performance.

  • Portable - supplied in its own carry case, the unit is small and lightweight making it ideal for use in on-site visits.
  • Easy to use - select the required wiring configuration and the logger will display step-by–step instructions for the coil and cable connections.
  • Quick and easy coil fitting - current is measured using non-invasive flexible coils that can easily be clipped around conductors (where larger rigid clamps may not fit) and the voltage reading is taken from a standard mains cable.
  • Self-configuring - once connected the unit will self configure and current, voltage, power and power factor readings will be displayed.
  • No complicated set up procedures - current coils do not have to be connected in the direction of the current flow and coils do not have to be matched to specific sockets. The coils supplied can loop around conductors up to 85mm, or 175mm, in diameter.
  • Spot checks or long-term monitoring - the unit can be used for spot checks or for longer term monitoring to build up energy usage profiles.
  • Onsite PC not necessary - logging is started at the press of a button; no computer is required to start the data logger. Recording can be started and stopped multiple times to allow different pieces of equipment to be monitored in one visit. Separate files are created for each logging run, ready for viewing in Tinytag Explorer.
  • Simple download, display and management of data - data is viewed and managed using the intuitive Tinytag Explorer software and data can be easily exported to spreadsheet programmes such as Excel. For profiling buildings, data can be combined with temperature and relative humidity data from other loggers in the Tinytag range.
  • Hanging option - there is a magnet fitted to the back of the logger so it can be attached to metal panels whilst in use.

Logging Interval: 30 seconds to 10 days
Reading Capacity: Six weeks at the default 5 minute logging interval

Current Range: 2,000A AC RMS (Momentary peak surge current: 2x rated range), resolution 0.1A
Voltage Range: 200-253V AC nominal, resolution 0.1V.
Frequency: Nominal 50/60Hz

Operational Range: 0 to +50°C, 95%RH (non-condensing).
For indoor use only!
Case Dimensions: Length 195mm Width 102mm Depth 50mm
Weight: 600g
(Including batteries)
PC Connection: USB
Rogowski Coils: Coil Thickness (Diameter) 8mm Internal Loop Diameter, 85mm or 175mm, Cable Length 1m

Mains Power: UK or EU Mains plugs, 200-253vAC
Battery Type:
4 x 1.5V AA Alkaline Batteries
Battery Life: 60 days, typical, based on a battery capacity of 2500mAH*
Logger Current: 1.5mA (10mA when display backlight is on)

When fitting batteries, observe the correct polarity. *When a mains lead is plugged in, the logger will be mains powered. If the mains should fail, the batteries in the logger will typically keep it recording for 60 days.

How The Energy Loggers Works

Voltage - Mains voltage is measured by direct connection to the mains supply. The data logger samples the voltage signal at 1kHz for 100ms to calculate RMS voltage and true power.

- Current is measured using flexible rogowski coils. They measure the current passing through the conductor which they are wrapped around. The current measurement is relatively immune to interference from currents in conductors which pass nearby, but not through, the coil. The data logger samples the current signal at 5kHz for 100ms to calculate RMS current and true power. The analogue current signal is filtered before being sampled. This ensures that the true power figure can be calculated accurately, even if the current signal has very sharp spikes. However this filter means that the RMS current figure displayed and logged by the data logger will be an underestimate if the current signal has very sharp spikes above the 6th harmonic.

True Power
- At 1ms intervals (1kHz) the data logger multiplies together the instantaneous current and instantaneous voltage samples. The average over 100ms (five or six mains cycles) gives true power. This figure appears on the data logger display.

Three Phase True Power
- The data logger can directly measure the current in three conductors simultaneously, however it can only measure the voltage of one. The data logger generates equivalent voltage signals for the other two phases by delaying the measured voltage signal by one third and two thirds of a mains cycle. This is effectively assuming that: The phases are separated by 120°; The phases have the same voltage magnitude; Any voltage harmonic distortion is identical across three phases. These assumptions may typically lead to an error of up to 1%.

Average and Peak
- The 100ms burst of readings is repeated every two seconds (this is reduced to every five seconds if logging on batteries, to conserve battery power). The Average Power trace shown in Tinytag Explorer is the average value over the 5 minute logging interval - an average of 150 true power calculations. The Maximum Power trace is the largest value calculated over the same interval. Maximum Current is calculated on the same basis.

Per-Phase Power
- In some configurations Tinytag Explorer will display three separate traces for the power transferred by each of the three phases. This is in addition to the Overall Power trace. The per-phase power traces are calculated assuming that the load is wye connected. That is, that all the current in each phase returns through neutral. This assumption is often entirely true, for example if the three phases power lighting and office circuits. The per-phase power traces can be used to judge the balance between those circuits. If the three phase load is delta connected then it is not physically possible to break down the overall power into per-phase components. The per-phase traces are meaningless and should be ignored. Only the Overall Power trace is useful.

Parameters displayed and logged

Parameter Logger Display Tinytag Explorer Software
RMS Current (A)
Peak over logging interval
Average over logging interval

Per phase

Per phase
Per phase
RMS Voltage (V)


Power (kW)
Peak over logging interval
Average over logging interval


Overall & per phase
Overall & per phase
Power Factor   Per phase
Energy (kWh)   Overall & per phase

Please note: this product is only for sale in the EU and Australia.

Availability: Stock Item


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