I've had quite a few cases lately where I start up my motors and Madame Graupner politely informs me that I have a compass error. Doesn't happen every time. Maybe every 2-3 times. And then it goes away. Tried calibrating, and that didn't help. Looked at the SD card in the Navi, and nothing was there because I didn't actually get into the air. Today it happened again, just as I was taking off. So I set it down and looked around. I noticed that my LiPo wires were every so slightly overhanging the GPS cover (and not really badly), so I unmounted my battery and turned it 180° so that its wires were coming out the back. And 4-5 flights later haven't seen the problem again. Take note if this has happened to you!
Oh, absolutely I do, but I'm running a single 8000mA LiPo and the battery leads were coming out towards boom 1 before they wrapped around to connect up to the leads from the PDB. I'll have to post a photo. I just turned the battery around 180° and I think that's the fix. It was exacerbated because I just got a couple of 8000mA Zippys, and they're a little flatter and longer.
Good to hear! I hope thats what it was!!! Do you twist your lipo wires together? The owner of the Mikrokopter.us site says longer lipo cables cause a lot of issues and recommends twisting all the leads together even the wires on the lipo all the way to the battery. I did this with the lipo wires all the way to the FCB and it creates a nice tight snug fit where I have no slack what so ever from the lipo terminals to the actual lipo battery.
The conventional wisdom seems to be that one should either (a) use heatshrink all the way along the main LiPo leads or (b) twist them. At currents of 60 Amps or more, they're generating a pretty strong electromagnetic field. I'm not sure which of the two strategies is better for heavy currents. Certainly for things like network wiring (much smaller current), twisting is the way to go -- that also helps eliminate common mode noise, I gather. I also braided each motor wire loosely to help reduce the electromagnetic field they generate when pulling 8-11 Amps. Andy.
I twist my lipo leads and then use heat shrink tubing to hold them in place while I solder the connectors on see attached pic. I then use a good amount of hot glue so that the connection between the wires and the connector so that the cable doesn't stress as much. I press those pins down pretty far into the blue connector but I am always paranoid about one of them coming loose out of the connector during flight.