eLogger V3 + GPS v3 + OSD Pro problem - RC Groups
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Jan 01, 2010, 02:54 AM
Registered User

eLogger V3 + GPS v3 + OSD Pro problem

Hello Bill,

Here's an interesting one for you. I have the eLogger V3, the GPS Expander v3, and the OSD Pro hooked together. When this system is powered by the computer via USB, everything works fine. When the system is powered by battery (through the eLogger's input), however, the video image from the OSD Pro becomes unstable (it flickers as if power cycling over and over) and all OSD graphics disappear.

Unplugging the GPS from the system "solves" the power problem. I carefully inspected the GPS and it looks like the little pen-cell battery has failed: there's corrosion (a.k.a. "the fuzz") all over the terminals. The GPS receiver itself does work -- because I can get a fix with it -- but it takes a very long time... which leads me to suspect that the battery backup unit is dead and the receiver is doing a cold start every time.

I'm pretty sure the GPS has to "come home" for an RMA...


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Jan 01, 2010, 04:19 PM
Registered User
I think this is Power issue described in documentation. What battery Your use?
Jan 01, 2010, 05:21 PM
Registered User
I've tried a 3s1p 500mAh battery and a 3s1p 2200mAh battery. Same results. Both battery packs are fully charged. Which documentation are you referring to? (i.e. OSD Pro, GPS, or eLogger V3 manual?)


Jan 02, 2010, 04:48 PM
billpa's Avatar
Hi Victor,

Sorry to hear about the issues. Yes, this is definitely the issue described in the manuals (all of them) but we need to do a better job of calling it out. The on-board eLogger regulator can't power all 3 devices. If you connect your OSD Pro to your Rx, the problem will be eliminated. Alternatively, you can use our battery backup harness (or your own equivalent):

Re the fuzz on the battery, that sounds like the battery may have failed, but it may also be a byproduct of the assembly (assuming it was always there). A quick check would be to leave the GPS disconnected for an hour or so after having it plugged in for a few minutes, and using a voltmeter to check the voltage on the battery. Or, we can certainly do that here via RMA.


Bill, for Eagle Tree
Jan 04, 2010, 03:21 PM
Registered User
Afternoon Bill,

Thanks for your thoughts re: the GPS battery issue. I did something along the lines of what you suggested, but in a less "invasive" manner (as I didn't want to remove the shrinkwrap from the device -- does that void the warranty?).

I connected the GPS (with a suitable power source), got a fix, and left the unit running for over an hour to charge the backup battery. I then removed the power source, left the unit unpowered for about thirty seconds, and then reconnected the power. I then measured the amount of time it took for the GPS to regain its fix. It took over 2 minutes -- which suggests to me that it performed a cold start.

My conclusion here is that the battery is inoperative as otherwise it would have performed a hot or warm start and regained its fix much sooner. I was careful to perform this test with a clear view of the sky to ensure that the GPS could obtain a fix as quickly as possible.

Anyway, long story short, I'll submit an RMA ticket via the support tracker.

And thanks, Bill, for the clarification re: the power supply issue. I'll connect up 5V+ via an RX/BEC to the USB port to power all my "joy".


Mar 10, 2010, 10:32 PM
Registered User
sf51177's Avatar

Need Help!

Because I think my OSD have the similar problem, it is better I post my posting here.

My Eagletree system flickers on and off (both video and text) but it doesn't "reboot" by showing the start up screen. It look like something is interrupting the system. I'm using elogger V3, Altimeter and OSD (standard)

When I connect the camera directly to my video Tx, it become stable and very clear. Do you think it is the power problem too?

Mar 17, 2010, 12:36 AM
billpa's Avatar
Hi Shawn,

That sounds like a power problem to me. Do you have any of the OSD Pro's servo connectors connected to your receiver?
Apr 29, 2010, 08:02 AM
Registered User
Hi billpa, when i connect the GPS expander to V3 elogger the OSD information vanishes. the video pic stays there but the parameters no longer get dispalyed. I am using OSD pro and V3 elogger and GPS expander of eagletree. please suggest what should i do?
May 06, 2010, 02:43 AM
billpa's Avatar
Hi, this sounds like you may not be using the battery backup harness, or connecting one of the OSD Pro's servo leads to your receiver? One or both of these is necessary since you are using the GPS, because the eLogger's regulator can't power all the devices.

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