Eagle Tree Systems eLogger V3 Review

Eagle Tree Systems eLogger V3 Review

The eLogger V3 from Eagle Tree Systems is an in-flight data logger which continuously records volts, amps, watts, and milliamp-hours to enable pilots to analyze the performance of their electric power systems. In addition, it supports a wide variety of optional sensors to record altitude, airspeed, component temperatures, RPM, and more.

The eLogger is a small device which continuously records these values to its internal memory. Once back on the ground, these log files can be downloaded to a computer for graphing and analysis. The device can also be used to display live values for all of its sensors, which means it doubles as a wattmeter on the bench.

Eagle Tree Systems provided me with the eLogger, a PowerPanel LCD display, two different temperature sensors, and an RPM sensor for brushless motors. All of these can be connected simultaneously, and still have room for a third temperature sensor and either a second RPM sensor or a throttle sensor. In addition, there is an altimeter, an airspeed sensor, a servo current meter, and a GPS module available. The variety of sensors and the ability to use so many of them at the same time is one of the major strengths of this product. The eLogger competes with the Oracle Data Recorder from Medusa Research and the eFlightWatt Data Logger from Mile High Wings.

Besides acting as a simple wattmeter, all of the attached sensors can display their live values on the PowerPanel, which is very configurable. From the PC software, you can choose which parameters are displayed and where, give them customized three letter names, and set up multiple pages of information. For example, eight parameters can be spread over two pages, which alternate every two seconds.

Even better, there's an option to show the maximum values attained since power on when the current is zero. This is useful both on the bench to check peak amps, as well as at the field after a flight. The latter is particularly useful if you want to try out different props but not bring a laptop out to your flying site. On larger models the LCD could be mounted in the fuselage or under the canopy to make it visible. For smaller planes or helis, the PowerPanel is best kept on the ground, and connected when needed.

The desktop software can be used in live mode, where all parameters are displayed in real time on large readouts, and optionally recorded. There's even a live mode for the graphing feature, which is extremely cool (although perhaps less useful than the gauges and digital displays).

Next I moved on to recording in-flight data. The Data Recorder application is used to configure the logger's behavior, which is retained in the absence of power. You have a choice of which parameters to record, and how often to log them (from 1 to 10 samples per second). These choices affect the total logging time available, as does the data compression used internally. Eagle Tree state a minimum of 45 minutes of recording time. I set up the logger to record volts, amps, RPM, and one temperature value, sampling 4 times per second. In this configuration I'd estimate 2.5 hours of data can be stored.