Eagletree Systems MicroPower E-Logger Review with V2 Updates! - RC Groups

Eagletree Systems MicroPower E-Logger Review with V2 Updates!

Frank Davis has a great time exploring this exciting, tiny new release from EagleTree Systems -- a micro sized logger specifically for electric modelers, with realtime data and playback of exactly what occurred on your flights! NOVEMBER 20 2006: UPDATED to include info on the newest, V2!

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Watt Do You KNOW?

Measurmnts: (approx.)2.25"x1"x.5”
incl sensor pins
Weight:.5 oz. (17g)
(wired version slightly heavier)
Current Draw:approx 35mA
Min Operating Voltage:4.5V
Warranty:1 year, limited, non transferable
Recordable Data:
Data Types:Pack Voltage
Pack Current
RPM (optional)
Temps (optional)
Amp Limit:100A
Amp Resolution:0.1A
Voltage Range:5V-45V
Voltage Resolution:0.1V
Logging Rates:1-10/second
Record Time:Varies; 20 min. minimum
Live Mode?Yes, live data on PC screen!
Upgradable?Yes, via Internet download!
Data Compression?Yes, Loss-less
Options:PowerPanel LCD Onboard Display,
RPM Sensor (100-50K+),
Temp Sensors (0-424F)
Data Full Options:Stop on Full
Rewrite Earliest Data

Germany/ Austria:http://www.rc-electronic.com
Israel:Tisanei Modiin
Japan:Albamodel (flight products)
France:RB Products
Scandinavia:Brother Hobbies
Singapore and Indonesia:Imminent Racing Components Singapore
Netherlands:Two Brothers RC
UK:Allendale Electronics Ltd.
Italy:Alewings Electronic Equipment
Spain:ROI Import
US:Local Hobby Shop or EagleTree Systems

Ever since I started working with electric flight seriously, I realized there must be a lot of things going on with the electrical power system that I didn't understand even though I felt I had a strong background in electricity. Slowly, I started learning the tools available to the RC electric flyer that would give me insight into what was happening with my power systems.

I remember one day going out to the field with my new plane and talking to a fellow pilot and saying, “I think this setup is drawing about 30A.”

His question was cold, direct, and effective: “How do you know?” I proceeded to tell him how I had used the latest computer calculations with my motor parameters, volts of my pack etc.

He asked again, “How do you know it is 30A?” I was stumped. He turned around, pulled out his fancy clamp on amp meter and said, "You don't know, but let's find out!" So we did, and it wasn't exactly 30A either.

There was a lesson that day: you don't know unless you measure it. So, I went about measuring every aspect I could. I made videos of motor and battery combinations with meters mounted to the static plane, so I could see all the measurements at once. I would measure RPM, AMPS, VOLTAGE, AMP-HOURS, everything I could get a meter on!

I was feeling better, but slowly the question came back to me, especially after I burned up another ESC, and some motors unexpectedly in the air! How do I know what's going on once that plane leaves my hand in flight? I wasn't measuring the real flight conditions, so even with all my efforts I still didn't know what was happening "up there", and it was costing me money. Now I admit, I always was trying to push my systems to their limits, and that was part of the fun! But no one likes to see something go up in smoke and not know exactly why. The fact is that there was nothing reasonable to make these much-needed measurements in a plane in flight!

But, now we do have this valuable information in a compact, robust, lightweight, unit: The MicroPower E-Logger by Eagletree Systems. If it saves you from one burned up electrical component, it will have paid for itself. If it tells you why you burned up a motor, (maybe it wasn't your fault), it will have paid for itself. And, for me, if it allows me to know how close to the edge I really am, that's worth it's money too!

Look at these features for about $70 bucks!

  • Logs pack current to 100 amps and voltage 5 to 45 volts
  • Accepts optional inexpensive sensors for 2 Temperature and/or RPM, available from manufacturer/distributors
  • Weighs about 0.5 oz. (17 grams). Version with Wire Leads weighs slightly more.
  • Supports USB Live Mode, which lets you see what's happening in the model LIVE on the bench, on your PC
  • Adjustable logging rate (1-10 samples/second) and loss-less data compression
  • Comes with state of the art Windows virtual playback display and graphing
  • Powerful Graphing software has advanced charting features, such as amps vs volts
  • Internet Updatable firmware - if there is a new feature or (heaven forbid) have a firmware bug, the update is just a download away!
  • Has Windows-based software with analog and digital gauges that play back the flight parameters with time line.
  • Allows you to see the whole interactive picture of the flight!

This is a lot of real fight data that, at first, is almost overwhelming when you get started. What happened to me is that I didn't have all the extra sensors plugged in.

The First Real-World Test – Death of a Chilli Pepper

But as luck would have it, I burned up another motor! Now at least I had some of the data, but realized I could have had the temperature feedback to be able to see at what temperature the motor failed.

I have some Chilli-Pepper 3600 Motors -- an older version and a new one. I put the older one on the plane with 3S 1500 pack (MaxAmps), a 10X6 prop and 3.8:1 planetary gearbox. Well, I went a little rich on the throttle stick and burned up my old pepper! But I had an Eagle Tree Micro Logger on it and could see what happened. Can you say over-propped? Look at how long the amps curve is about the 20A mark. There’s the killer!

It was a new plane, new gearbox, I guessed this prop should work, and it all seemed reasonable. I knew from my static tests that WOT would be pushing the motor a bit, but…a little self control and it should be fine! J I thought I knew enough about this motor and electrics in general that I expected it to work.

After the burn out I went back and got the mfg's specifications. Oops! the Chilli went 20% over burst rating of 20amps, then took on some more abuse.

A Careful Look at Minimums, Instead of Just Maximums

I decided at that point to determine the minimum wattage at which this plane could fly. I propped down to a 9.5X6 prop, and the rest of the configuration was the same as before. This is actually a new idea for me! And I wouldn't have even thought of it before my MicroLogger had come along. I'm one of those guys that felt as if I had to over-power everything to help prove electric's could do anything. Now it's a silly and wasteful idea to make all your power systems that way. I think electrics are proven and everyone should know we are here to stay.

Here's some flight data to show what minimum wattage will allow my new Combat Corsair to launch, loop, and cruise.

Here's the data from another flight. It was pretty windy, but the plane took it well. You can see she will sustain flight on less than 60 watts! I wouldn't try rolling her, but it was very impressive. Her AUW is 2Lbs 6.7 Oz. For me, this breaks the old rule of thumb of 100 watts per pound for powered flight.

Please note that the real Corsair flew on about 43.9 watts/pound max HP rating. Of course, it has much better Re numbers from her big wings. So, you don't really want to power her with "scale power". But, by taking these measurements the MicroPower E-Logger gave me some hard numbers for minimum actual flight requirements that I could share with others, compare against other planes, and better qualify your power requirements. That's simply amazing!

Bench Tests, Too!

Don’t forget, if you want to bench test your plane for static results, you can bring your laptop over and hook the recorder up to the USB port and watch the real time results from static testing as well. The recorder will be recording these tests as well, even in live mode. Then you can share and review that information with others before you even fly the plane the first time.

Returning to the Chilli Line…Without Feeling Gunshy

The other way to look at this data is that once I burned up the first motor, I'm a little gun shy, and actually not using my power system to its full capabilities. I could stand to fly a little hotter now and pretty much know with the new prop it will be ok. Yet another fact I learned from this data was that once I started to measure temperature of the motor, I might be in risk of heat damage to the magnets after the plane has landed! The motor is surrounded in cowling and once landed it has no airflow, and the heat is reflected in the cowling. This has changed the way I handle my plane after each flight. I now run over, and pick up my plane quickly. I then hold her nose up and turn on the prop for a little while as I walk back to the flight line to get rid of any heat build up and cool the motor.

Running the prop with low RPM's has shown this to be effective at removing the waste heat from the motor after the flight. It seems obvious now, but I don't think I would have thought about the issue until much later, if at all, before failure occurred.

Measuring RPMs

Another interesting parameter measured is the RPM's. Below shows the simple steps I went through to install the magnets and RPM sensor on the corsair project.

Some people might question why would you want to measure the RPM's. There's a lot of information that can be uncovered by measuring the RPM's of the Prop and motor combination. Some are pretty direct, others are results of calculations that are beyond the scope of this review. One of the first things I wanted to know from RPM measurements is that my motor is turning the prop in the expected range. It also will show if the prop is unloading during flight. These aspects help determine if you have properly setup the motor gearbox combination to run things efficiently. After a few flights, you can also use this as a trouble shooting tool. If there is a loss of RPM's relative to a certain current draw you may be having problems in your gearbox, your magnets, bearing, and it may be time to investigate these type of issues and stop flying until resolved.

The Practical Side of Things

So let’s look at how this product affects your workload as you start to gather things together and get into the air. I have found that this device is so easy to install and utilize that there’s very little added mental overhead on flight day. That’s because if you really want to minimize your fuss, you can forgo some of the features (temperature, RPMs, and such) and just plug it in and just monitor the current and voltage dynamics of your flights.

I have one plane setup with all the sensors I can manage, I find myself just pulling the data logger out of that plane and plugging it into some other plane for a flight or two then putting it back in my main test plane. If you have standardized on battery connectors like I have, this is so easy it’s silly not to do. If you choose to hook up your other sensors, it’s as simple as connecting servos -- just be sure they are correct in polarity (as shown on front sticker) and firmly in place, pushed all the down on the pins.

This data logger is very rugged! Several times I have gone to the flying field during lunch break and at the end, pulled the recorder out, stuffed it in the small “watch pocket” of my jeans, and then later downloaded the data. All I have had to do was straighten out a few of the bent pins and plug it in. This kind of ruggedness proves to me that it is a very practical tool to bring out to the field every time.

Extracting the Data

Now you that have your flight data logged, how hard is it to get that data back out? It’s easy! Just fire up the program from your desktop Icon, plug it into your computer’s USB device port, connect the RC type connector to the USB port on data logger, wait for your computer to recognize the new device, and under “tools “ then select “download from recorder”. You will see the download bar come up, letting you know it’s working.

NOTE: if it’s too quick, you didn’t get much data! It never takes a long time but if it’s just a flash, I get nervous.

Playing with the data

I can honestly say that it could take an entire series of reports to breakdown all the results you can derive from the data this small device records! What I experienced is this. The more I sat there and studied the results from the powerful graphing section in the software, the more I learned. You won’t see it all at first, and it is a little intimidating to start with. What helped me to get a handle on these graphs is to start removing some of the data series and look at one or two at a time. Try zooming in on a small area or event, this could be on a big loop you did after gliding for a while, for example. I often use the RPMs as a reference point to compare other recorded dynamics against.

This software also comes with the cool analog meters and digital meters that make your PC look like the cockpit in a modern fighter plane! It actually does more than that. It helps me to get a “feel” of the flight. As you play back the downloaded data on the gauge screen, you start to see what the “concert” of the flight dynamics was doing all at once and in real time speed. This effect works best the sooner you play it back after the flight..so you can recall the things were going on in the air. Or if you video tape the flight, that just ROCKS!


I don’t know what more I can say. Bang for the buck? It’s an atom bomb for the electrical flyer. To buy good quality separate meters to reproduce the information the product provides could cost you several hundred dollars. Even then, they don’t data log in flight. If you are in a location where the local people don’t understand “that electric stuff”, with this logger you can share all the information with people who do understand on places like RC Groups Forum, giving them hard facts to help you explain your issues.

I see this product as another fine example of what the exciting electric flight products have come to offer us today.

Updates for the Micro Power Logger

The folks at Eagle Tree Systems have continued to improve and update the Micro Power Logger. Hardware, software, and accessories have all been looked over and changes made to improve user friendliness and functionality.

First the Hardware improvements:

The controller board is new on version 2, and has stamped V2 on the bottom of it. The V2 supports the 3 wire version of the optical sensor, the V1 requires the 4 wire sensor. On the 4 wire version there's an "extra" pin on a wire that has to be plugged seperately into the port below for it to work. The controller is now sporting a new metallic label that’s more durable than the paper version which it had before.


Temperature Sensor

The new Micro Temperature sensor is smaller and lighter than the original Loop Around Temperature sensor. The Micro Temperature sensor is rated for 250 degrees F which can be prefect for several applications like motor case, battery, ESC, or gearbox temperature monitoring. The one advantage of the Loop around Temperature sensor is that it can go as high as 420 degrees F. So keep that small difference in mind when ordering.

RPM sensor

Here again the sensor has gotten smaller and lighter and is very easy to use! The new sensor is an Optical sensor instead of the original hall effect sensor type. The optical sensor eliminates the need to have a magnet installed into the propeller hub for RPM sensing. The new RPM sensor it optical and has it's own light source built in. It works by seeing the difference between dark and light color solid surfaces via this light. It is expecting to see something like a disk colored half black and half white. This is a little different than many “typical” optical RPM sensors that count the propeller blade “blink” as it passes by and is dependent on ambient light sources. One neat trick for outrunner motors is to put masking tape around the motor and color half of it black (sharpie) and leave the other side to act as the light part of the disk. This allows for protected and easy mounting of your sensor internal to your plane.

Power Panel

The Power Panel is the biggest addition to the Micro Power Logger. It adds more flexibility to the applications of the Micro Power Logger. It allows you to see the real time information the data logger is getting without the need of a computer! This is useful in field for trouble shooting and testing or on your test bench for testing things there. I haven’t used it mounted on a plane because for me, I like to move it from plane to plane for each flight or test. The Power Panel allows you to display Amps, mAH, Volts, Temperature, Wattage, and RPM. The software allows you change the most important parameters to the first pages and determine how the information is scrolled for your viewing. This LCD display is ultra thin, and light, so there’s no need to worry about the additional weight, if you do decide to mount it on a plane, except on the smallest of planes.

Software Upgrades:

Easier to read numeric displays

  • Support for prop RPM as well as motor RPM
  • Persistence of all graph settings. This version saves all settings made under the “settings” tool of the graph, as well as X-Axis settings. It also does away with saving/restoring “.TEE” files. Those files do not really serve any purpose, now that we automatically save/restore the settings.
  • Logging triggers – now you can set the following logging triggers: time, amps, RPM
  • Graph menu change – now only the MicroPower graph options will show up in the graph menus
  • Graph color changes – the colors are now easier to tell apart on the graph.
Last edited by AMCross; Nov 20, 2006 at 11:56 AM..
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Feb 23, 2006, 12:16 AM
I'm Charged!
megawatt's Avatar
Excellent review Frank. It makes me wish I had one YESTERDAY. Can't wait to get my hands on one just to see how close my own "calculations" are!

Feb 23, 2006, 12:37 AM
Radio Up Flyboy!
flynfrog's Avatar
Frank, another Great Review.... Would this system be convertible to a Heli? It would seem that "Over Proping" would be the same as "Over Pitching" for a given throttle curve. This Logger / analyzer may help a few of us better maintain / save / reduce abusing our LiPo packs.---

Feb 25, 2006, 09:41 AM
Registered User
frankswd's Avatar
It would work for a Heli, you would have a bit of weight penalty but it would be a good tool for getting your setup dialed in.
Mar 06, 2006, 10:54 PM
Registered User
Captain Carlton's Avatar
Hello All.

I just got the basic Eagle Tree FDR, and it works great. I didn't go with the RPM meeter, just interested in Amps, Volts, Temp, and Watts. It rocks. My basic need to to understand what kind of power my motors are putting out, etc, can my Lipos take the loads, etc, etc. As summer approached, I need to know how warm my motors are getting.

I wish they had a Mac version of their software. Oh well, I know I kept that klunker of a Windows machine arround for a season.

Good job Eagle Tree!
Mar 07, 2006, 08:54 PM
Registered User
frankswd's Avatar
I would be interested in seeing your voltage data as well and more info on your batteries. maker, capacity etc. I assume all shifts in current draw were the results of throttle action, right?
Mar 08, 2006, 02:08 AM
Registered User
Captain Carlton's Avatar
All major shifts were a response to throttle action. The battery was a 2500mah 3P Pack from Duralite. The downward swing at full power is function of the battery. I did not overlay the voltage on that screen shot. You can do that, and it shows you the corresponding sag. I did not keep the data. I keep the screen shots fro reference. Great tool. Pretty interesting stuff.
Mar 25, 2006, 03:25 AM
Registered User
One correction:

Your article lists the weight as 0.5 oz - but then says 17 grams. Half an ounce is 14 grams, not 17. So, which is it?

Another thing, your article sounds a little too "gushing" to be taken seriously as an objective article. Especially when you say things like "state of the art software." What exactly is it that makes it so state-of-the-art?

One thing I would like to see in future versions of such a product, is the tracking of control inputs from the receiver - especially throttle. But I would most like to see a lighter version for smaller models. At 17 grams, it seems heavy.
Mar 26, 2006, 11:54 AM
Registered User
Captain Carlton's Avatar
The model that was reviewed, and the one I own, is the basic low end unit. Eagle Tree has a high end unit which tracks EVERYTHING...Servoes, GPS coords, live data transmission, etc. Its like $500, so outside my price range.

- RC
Apr 22, 2006, 09:46 PM
ProBro Eric in Jax
p0stal's Avatar
Great product. Have flown it in all my parkflyers. Great feedback, takes out all the guess work.
Apr 25, 2006, 12:03 PM
Registered User
Can anyone compare this product with Black Box from MGM compro? The URL is http://www.mgm-compro.com/index.php?tid=black-box-bb03.
Apr 26, 2006, 10:01 AM
Registered User
frankswd's Avatar
An interesting device. I'd have to see it or test in person to really know the differences. Seems pretty cool however.
Apr 27, 2006, 08:51 PM
Registered User
What happens if you exceed the unit's perameters? i.e. if you exceed 100 amps, does it burn out or just not revord above 100?
May 03, 2006, 10:17 AM
Registered User
Originally Posted by SstickDMH
What happens if you exceed the unit's perameters? i.e. if you exceed 100 amps, does it burn out or just not revord above 100?

I emailed eagletree and their reply stated that it is OK as long as you do not exceed 100 amps for too long. Doing so may risk damaging the connectors.

May 05, 2006, 10:27 AM
Registered User
Just got mine yesterday. I only had time to try one run so I slapped it in my RC10-T3 truck with a 7 cell NiCad. I did not get the RPM meter, but I did use the temperature probe around the motor. Very interesting to see the data. I saw very short peaks of current near 80 amps with continuous current being between 20 ~ 25 amps.

I mainly want to run this in my airplane, but I am still building that. Should be good in another week or so.

Also, I have a brushless EMaxx monster truck that weighs in at 13 lbs. It is insanely fast but does have problems with large battery packs. This should tell me if it is a temperature problem or a current problem. I am sure there will be brief peaks over 100 amps, but continous amps should be closer to 50 amps. I will let you know how the peaks are graphed when it exceeds 100.

So far, I really like what I see with mine.


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