Progressive RC has a wide range of products of particular interest to the electric R/C modeler. Their offerings include chargers, power supplies, balance boards, cables, tools and accessories. One of those accessories is the PowerLog 6S that we received for review. This versatile tool combines an in-line amp/watt meter, cell monitor, and data logger in one product. Read on to see what we discovered about this little gem…
- Wide range of applications and uses
- Outputs to PC or laptop for graphic flight analysis
- Supports multiple temperature sensors so you can monitor ESC, battery etc in flight
- Comes pre-calibrated and appears very accurate.
- Includes features for our aircraft friends like a built in optical tach that measures up to 30 blade propellers!
- Back-lit display is easy to read in both low light and bright sunlight.
- Even at .5 sec sample intervals the unit holds over 8 hours of data. That’s a lot of 6 minute flights!
If you’re going to be serious about flying electric, especially the larger stuff (and by larger I mean over 450 size helicopters), it pays to know what is really going on with your power system. The PowerLog 6S, while not much larger than a credit card, and less than the cost of a 4S battery, packs a wallop of functionality. Examining post-flight data eliminates much guess work and gives you hard data on several pieces of important information.
- Battery voltage under flight load. Especially useful for spotting trends when a battery is going bad, as well as ensuring that a battery is performing up to its (often optimistic) C rating. Graphing allows a direct comparison between the amp draw and the battery voltage at varying loads.
- The actual number of amps your battery/ESC/motor combination is pulling under load. Lets you know if your components are well matched and you have a comfortable safety margin or if you are operating on the ragged edge of puffing batteries and burning up speed controllers.
- Brushed and brushless motor RPM. Shows you the difference between theoretical KV ratings and whats really happening. I found this worked well for my airplanes where I could visually see the difference between ground runs, and what happens in flight when the prop unloads.
- Multiple temperature monitors lets you examine temperature data from critical components that often cool down in the time between peak flight temperatures and when we can check them on the bench after a flight.
- Use the total miliamp draw from your log against your charger data so ensure you aren’t over discharging your batteries.
- Alarm feature lets us know when a wide range of conditions are met or exceeded.
I’ll be honest, when I first sat down with this thing I was almost a little intimidated by how many functions the PowerLog 6S will perform. I set the unit aside, downloaded the instruction manual, and spent some time familiarizing myself with the features. Just about any port will power the unit so you can connect a LiPo to the deans input, a balance connector to the balance lead, a standard NiCad flight pack to the other side, or plug it in to a PC via the USB port. I found it especially useful to be able to scroll through the menus while examining the instructions to get a feel for the logic flow of the unit so I plugged it into my USB port while reading the online manual.
The manual itself is good and heavily illustrated with flow charts to walk you through the device menus. It does assume some degree of subject expertise but with a little bit of experementation, both the manual and device become clearer the more you use them.
There’s only 3 buttons on the unit but each performs a number of functions depending on where you are in the menus. Also each button performs a different function if you press it momentarily or hold it down for 3 seconds. I decided to start simple and work my way up. To test the watt meter I connected the unit in-line between the battery and speed controller on a new project I was working on, a EDF U-2 spyplane from Hobby People. The power system components were generic and I wanted to see if the battery they supplied could handle the load and ensure that the fan wasn’t pulling more amps than the speed controller could handle.
The unit paid off as soon as I connected the LiPo battery that was included with the kit to the the PowerLog 6S. The plane had come complete with a balance charger and I had used it to charge the 3S battery, but when I plugged the balance lead of the battery into the PowerLog the voltage readout showed that the battery cells were badly out of balance. I connected the battery to my Hyperion Duo and confirmed the readings from the PowerLog and used the charger to discharge the high cell to get the battery back in balance. I thought maybe it was because the battery was new but I confirmed the charger was bad after several cycles.
Before I even had a chance to scroll through the menus the PowerLog 6S may have saved me a $250 dollar plane!
As I progressed through learning about and testing the unit, I added features as I went along. After I became familiar with its operations as a watt/amp meter I added the external temperature sensor and attached it in turn to the battery and ESC to see what kind of temperatures my installation was running. The PowerLog comes with 1 sensor but you can connect up to 3 external temperature sensors so you can monitor both ESC and battery temperature during flight. The unit also outputs its internal temperature for a total of four temperature read outs and can be set to use either Fahrenheit or Celsius.
The next thing I unpacked and checked out was the motor RPM sensor cable. This works either with brushed or brushless motors depending on how it’s connected as shown in the heavily illustrated manual. As I said above, this is useful for obtaining your motor RPM to give you a practical number to work with when experementing with pinions or different size props.
I didn’t have a chance to make use of the servo drive or pulse width checker as the cable needed to do so isn’t included with the unit. I already plan on ordering the cable so I can expand my uses for the PowerLog even farther.
After a few test runs and some back and forth between the unit and the manual, I figured out how to get the logging working correctly. This is where I ran into the only snag in my experience with the PowerLog and it’s not really a problem with the unit itself. The 3rd party log management software that you have to download uses German as its native tongue. Even if you change the language settings to English several menus and options still show up in German. When you save a file for example it asks you to confirm with “Ja” or “Nein”. Nothing I couldn’t figure out though. Also the logging software loaded just fine on my Windows XP machine but wouldn’t run on my Windows 7 laptop.
A few tips to avoid frustration while installing and using the logging software.
- There’s a windows driver that needs to be downloaded from the web site before it works.
- In LogView, under DEVICE SETTINGS choose Junsi PowerLog 6S and for the port hit the pull down and select the USB port that your device is connected to. It won’t show up as a port until the unit is connected. (See screen shot)
- To transmit a new file, close down and reopen LogView, then select transmit from the PowerLog. I’m not entirely sure why this is but if I already have LogView open it won’t recieve the file no matter what I do till I close it and open it again. I attached a screen shot of the logging software and the correct device selection since the LogView software supports a whole host of log enabled devices.
I’ve exported a sample graph that has been created from a log file using the LogView software. You can see as the test run progresses from left to right the blue line tracks the cell voltage as it drops across the chart as well as being pulled down when I went to full power. The brown line represents the amp draw and you can see it spiking at just short of 35 amps at full throttle. The light green line represents the total consumption and it rises across the chart and shows that I consumed 440mah of battery capacity during this run (confirmed almost to the miliamp by my Duo charger). The light blue line indicates the temperature rise though you can see that even though I had changed the logger to read in Farenheit, I forgot to change LogView and the temperature readout is shown as Celsius.
Overall, if you fly electric I think that the PowerLog 6S will be a worthy addition to your tool box. The information it supplies is valuable and I plan on using it to test and verify each new installation.
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