eLogger V4 & 12-cell LIPO - RC Groups
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Nov 25, 2012, 05:27 PM
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WEREE's Avatar

eLogger V4 & 12-cell LIPO

Hi Bill. I have a big Mikado Logo 500SE helicopter that I've been flying with FPV. Its been running nicely with the EagleTree eLogger V4 on 6-cell LIPO power no problems for a few months now. Even with it hitting 80A continuous current!

However, this weekend I maidened this exact same setup but now upgraded to 12-cell 50V power system. The eLogger V4 didn't work so well. The amp read out reads correct for a second but then jumps like +30A for no reason. This doesn't appear to be a calibration issue because the values jump to such a large degree and periodically every second or so.

On the ground, just sitting idle, the OSD amp readout is 0.2 as expected but jumps to 38A every second for no reason and then back to 0.2A! It does this continuously. The voltage is at the expected ~48.5V and correspondingly jumps down to 39V or so everytime the amp reading jumps up. The helicopter is idle on the ground with all systems connected but just idle. I have calibrated the amps and volts but, again, with erratic large periodic jumps in the readings for no reason, I don't think this is calibration related problem.

The AHI with the Guardian doesn't appear to work as before and the magnetic RPM sensor I use to show main rotor RPM appears to also be off. My eLogger V4 is having some serious issues with 12-cell LIPO power right now.

For interested forum readers, the eLogger V4 is capable of 80V maximum according to its product page.

Another very interesting thing is when I plug in the USB for programming the eLogger, everything works! Seriously. The amp and volt readings are solid and accurate and the guardian AHI is working. Could I fly by finding 5V power somewhere onboard and power the eLogger V4's USB port? As I understand it, USB standard is 5V power.

BTW, I fly with a secondary 3-cell LIPO to power the electronics with a regulator. It also feeds 6V into the OSD Pro servo pins as is my usual setup.
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Nov 26, 2012, 01:56 PM
billpa's Avatar
Hi Weree, for packs greater than 4S, the eLogger requires the battery backup harness (the throttle Y cable that was included with your eLogger) to be connected. Please see page 6 in the manual below for details on how to connect that:


If you already have it connected, let me know and we'll troubleshoot further.
Nov 26, 2012, 02:16 PM
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WEREE's Avatar
Hi Bill. Okay, this could be it. Interestingly, I've been flying 6-cell on all my EagleTree equipped FPV for years now and never need this extra voltage to the eLogger!

I do remember in the early days my OSD Pro video would shut down for no apparent reason. Until you directed me to supply some BEC 5V/6V input into the OSD Pro which has solved that problem completely. I take it now the eLogger is needing some supplemental voltage because its internal voltage regulator is overloading from the higher input voltage that the 12s pack is providing?

I'll try this tonight...
Nov 27, 2012, 03:56 AM
Registered User
WEREE's Avatar
Hi Bill. I believe this is fixed!

Earlier this evening, I powered on this 12S Logo 500 helicopter and observed the same problem I described above. Then I connected a male-male servo connector from the OSDPro ThrottleOut into the eLogger ThrottleIn and restarted the system and the problem disappeared. The OSDPro is powered by a 6V voltage regulator powered by the FPV/servo auxiliary 3s battery. Since the EagleTree RTH does not yet fly helicopters, all these connectors are free on this setup -- no Y cable needed.

Everything works as expected now including the Guardian AHI. I've had Guardian AHI issues before on 6-cell but everything else worked. I think I will attach this extra power cable into the eLogger to see if the AHI problems go away.
Nov 28, 2012, 04:00 PM
billpa's Avatar
Hi Weree,

that's great news!

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