3DR Quad - Power consumption and hot ESC - Discussions

I come to consult the Oracle!

I'm hoping someone out there can shed some light on a possible issue I have with my quad. I just tore the stock quad apart (was flying perfectly!) to install Tarot 2D gimbal w/ Gopro, video transmitter, and MinimOSD on screen display. I've installed everything and it functions as it should (OSD, gimbal, camera pitch RC control, etc)

The issue:

When I'm testing it (haven't flown yet), the #1 motor ESC gets VERY warm (motors are off). Not sure if this was an issue before the installation of all the equipment, but I definitely notice it now. When I'm looking at the OSD it shows between 1 and 2 amps with motors not armed. This is through the 3DR power management doohickey. I've tried my best to "calibrate" using a voltmeter and adjusting the voltage divider in APM. The stuff drawing power is APM, gimbal, Gopro, vTX, OSD.

Two questions:

#1: The consumption seems high which can be attributed to the Gopro charging. I've tried with a fully charged Gopro and it's around 1.5A, motors off. What are others seeing as their "standby" current? Is my power consumption normal?

#2: From what I've read about the 3DR power distribution module, it has it's own 5V regulator so it's not pulling from a BEC somewhere else on the quad. Is this correct and 2nd part would be, why is the #1 ESC so hot (the others are cold)?

Details:

3DR Quad c-frame

880KV motors (11x4.7 props)

4000Mah 3S battery

1W vTX - 12V Directly from battery

MinimOSD - 5V powered from 3DRs PDM / 12V powered directly from battery

Tarot 2D gimbal - 12V powered directly from battery

Gopro 3 Black - 5V powered from 3DRs PDM

I apologize in advance if this is the incorrect forum and accept the public flogging that will insue.

Thanks for any and all help! :)

Tom

Replies

Ravi January 15, 2014 at 8:56pm

@bill bonney, i intend to replace the 500mA fuse on old APM2.5 with a new 1.1A fuse i am expecting from 3DR. can you please shed some light on how to replace the fuse. what is the special care to be taken while replacing.
s3rp1c0 January 7, 2014 at 11:21am

Thanks Andke and Mike, I appreciate the reply.

I thought I read somewhere that the 3DR PDM was rated at 2.5A @ 5V but obviously I messed up somewhere. It makes sense to move it to a UBEC... going to find something ASAP.

It begs the question though, does the PDM use 5V coming from the #1 ESC then? Why do you think it was getting hot? I thought there was some kind of 5V regulator on the PDM itself.

thanks again for the insight...

Tom
Mike Boland January 7, 2014 at 11:16am

I am surprised your 3DR power module has not fried.

It is only rated at 500mA and you are WAY over that with the GoPro hanging off it.

As Andke said, you need a switching BEC, called a uBEC or sBEC, to power that sort of load.

The linear BEC's in the ESC's won't tolerate that for long either.

They are generally rated at not more than 2A, the more LiPo cells you run the less the current they will handle.

Sound like you need to rethink your power handling.
Andre K. January 7, 2014 at 5:43am

Linear regulators are not suitable for load like this, for every Watt you get, you convert more than two into heat.
Get a switch mode regulator, often marketed as ubec.

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