Watt Meter and Power Analyser

Review

Introduction
Radio control model enthusiasts use the ‘watt meter and analysing device’ described here to determine the electrical requirementsof their RC model. This is important to determine the battery storage requirements to meet the needs of the model commensurate with its usage.

I was interested to see if this device could be used to determine the electrical requirements of 12 (or 24) volt electrical equipment in a typical recreational vehicle (RV)The following review shows the device being used to determine the requirements of a typical 12 volt RV refrigerator.

Device Description
It is small, measuring 85mm x 42mm x 25mm. It has an LCD display permanently backlit. It is a four terminal device – two wires labeled ‘SOURCE’ and two wires labeled ‘LOAD’. These input/output wires have a copper conductor diameter of about 2.8mm – the ends are stripped of insulation and tinned. The analyser is inserted in the supply wires to the device under examination.

The device has four data fields: the top left displays the Amps, top right displays the Volts, the lower right displays the Watts of the consuming device.

The remaining field changes the information it displays every 0.4 seconds. The data displayed is Ah (Amp hour), Wh (Watt hour), Ap (Amps peak), Vm (Volts minimum) and Wp (Watts peak).

Usage
The photos below show the device in action. It is analysing the power consumed by a typical RV refrigerator.




And:



After being connected to the fridge for 24 hours it showed:
39.2Ah
472.5Wh
46.2Wp
3.88Ap
11.79Vm
The unit will reset when the input supply is interrupted.

Conclusion
Although intended for analysing the power requirements of radio controlled models, it seems perfectly suitable for ‘bigger’ things: I intend acquire another one and insert it between the battery charger and the battery.
I purchased my unit on Ebay bit.ly/Oo7bfn , around $30, free P&H
The item description is:
G.T.POWER Precision Watt Meter and Power Analyzer BK320


Gil Webster

Specifications
Operation Voltage:
4.8V – 60V
Measuring Range:
0 – 130A, resolution 0.01A
0 – 60V, resolution 0.01V
0 – 6554W, resolution 0.1W
0 – 65Ah, resolution 0.001Ah
0 – 6554Wh, resolution 0.1Wh
(Note: The 65Ah and 6554Wh are not a real limits as the displays roll through zero and start again.)
Accuracy:
Not specified; however it agreed to within 5 millivolts of my trusty DVM.