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Doing a burnout, not in a good way

Hi All
I had an interesting incident yesterday while operating my BR2 Heavy-- I lost contact with the vehicle for a bit, but it recovered, and when it did there was smoke visible inside the electronics enclosure and I had lost my two front lateral thrusters. Video of the event is visible here:

Now I need to figure out what happened and what actually died. I’m genuinely amazed that the vehicle recovered and kept going after whatever is was that went wrong, and upon inspection there’s nothing obviously burnt up and everything except thrusters 1 and 2 seems fine.

Update-- both thrusters test OK, so I guess both ESCs are differently dead. I’m going to replace all 6 of the old ones just in case, and swap my spare thruster in for #1 since it does feel different than the others.

Hi @rperkins Shoot, sorry that happened! That’s actually one of the first ESC blowouts I’ve seen. Usually when we had an ESC blow up on us it was because a bit of saltwater had contacted the ESC PCB, was still wet and powered on. We know how well saltwater goes with PCBs in general.

If it wasn’t saltwater, we have run a FLIR camera over an old BlueROV2 that had the old R1 ESCs and had been turned on. We noticed that the major heat concentration area is around the mid-section where the ESCs are.

I think you are doing the correct upgrade and maintenance here by upgrading to the R3 ESCs.

Thanks for checking in, Kevin. Everything in the enclosure was bone dry, so I don’t think it was a stray moisture problem. I talked with Rusty for a few minutes on Friday about this stuff and he had some good suggestions about avoiding heat buildup in general which I will employ in the future, too. I’ll be swapping in the new ESCs today and testing tomorrow, hopefully. I’ll bring my laser-thermometer thing with me, too.

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For anybody interested, here’s what one of the failed ESCs looks like:

Google Photos

The other one doesn’t have any visible damage.

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@rperkins It would be nice if you share thos advices about avoiding heat! :smiley:

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Hey @luisgamez, Rusty’s suggestions were pretty simple.

  1. Try to take it easy
  2. Do whatever you can to minimize heat buildup in the vehicle prior to launch and between launchings, like keep it in the shade, away from heat sources, powered off if possible, etc.
  3. An aluminum enclosure would help, too.
    After repairing my vehicle, I took it out again and had great success. “Take it easy” was the theme of the day. Here’s a picture of my setup prior to launch, note the towel covering the vehicle even though it was cloudy:

    I did some testing prior to this trip. I did full-throttle runs in various directions and orientations at different gain settings. At 50% gain, going directly forward or sideways drew about the same amount of power, around 250 watts, but “crabbing”, or moving at about 45 degrees from the direction the vehicle is facing, drew almost twice as much, around 450 watts. At 75% gain, full-throttle forward and sideways again drew about the same amount of power, around 500 watts, but moving at 45 degrees drew less, under 500 watts, very similar to the power draw at 50% gain. So on my dives the other day I kept the gain at 50% and did my best to move either forward or sideways and not inbetween, and I kept a close eye on the watts and internal temp indicators in the instrument panel in QGC.
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All good info. I find that it pays to put rov in water and let it acclimatise in temp first then lift it out and release the pressure in the electronics tube. Otherwise, regularly it would bleat over pressure alarm which would force me to bring it to the surface to release pressure anyway.
Make sure you put dessicant in electronics tube, as moisture can be pulled in when vent is out or during maintenance. Any moisture is bad coz it can also build up on inside of dome and turn good video into a hazy mess.