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Short circuit! XT 60 sockets on the motherboard must be equipped with fuses.
2226 7 2014-12-17
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knarfboy
First Officer
Flight distance : 494508 ft
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Germany
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A 16000 LIPO has by a short circuit over 1000 amps! A S800 has totaly burned out. The power supply cable from the XT60 connector for PMU is frayed and has caused a short circuit.

On next Hardware revision, please install fuses to each XT60 connector on the Board (S900 and S1000) Like 5 Ampere, to limit the current during a short circuit.

Like this:

Please give this Information to your Hardware developer!

2014-12-17
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DJI-Autumn
First Officer

China
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Sorry for your loss..
And thanks for your kindly remind!
I will report it to Hardware developer.
Thank you!
2014-12-18
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Blade_Strike
Super Moderator
Flight distance : 872694 ft
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United States
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I wouldn't want a fuse on my power system. Failure of that fuse would be just as bad as a short circuit if not worse.
Just like any aircraft, proper maintenance and preflight checks are required.
2014-12-18
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knarfboy
First Officer
Flight distance : 494508 ft
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Germany
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The A2 flight contoller system need 300 mA if  caused a short circuit. the cable will burn and destroy a lot. In this worst case your copter will crash even with fuse and without fuse too.

If you use a high-quality fuse holder, it will not fail. This should be a protective cap have, as in the picture. If you have a 5 amp fuse in use, this fuse burn  only in extreme cases.

A backup fuse for not fly important parts, such as picture transmitter, iOSD, gound station, data link or gimbal always make sense. This protects the other electronics from short circuit and reduces the risk of fire.
In this case a fuse will prevent a big short circuit and will keep your copter on fly.
2014-12-18
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Blade_Strike
Super Moderator
Flight distance : 872694 ft
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United States
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Missing the point completely. You should be checking the craft for any type of failure, this includes wiring. Just my opinion
2014-12-18
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knarfboy
First Officer
Flight distance : 494508 ft
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Germany
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Comparisons with a car. A car has 20 to 50 fuses, for almost everything.
If the fuse that protects the engine control unit, burns out, the motor stops immediately.

According to the rules, you have to  complete check the car before each drive.
The function all the bulbs. The tire pressure and brakes.
Now a real true answer from you. How many times have you done this year?
2014-12-19
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rubenmail
lvl.4
Flight distance : 1802270 ft
Norway
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I would like Blade_Strike not have a fuse as it would be hard to find a solution that take into account that depending on your solution and equipment and the battery you use. The battery might give a burst of "to much" at some time might cause a fuse to go and make a drone dive into a nice crash.

As you mention cars there is no fuse on any critical solutions like brakes and steering that might cause a car in motion to lose control and hit the ditch or another car. A fuse for not flight critical parts might be possible.

I check my cables as often as possible. Also I smell the rig after flight as that usually is the best sign of something is not as it should be.

A solution to what you are suggesting, but I dont now how heavy it might be, is to include digital absorbers that instead of clip the fuse store the extra energy and get rid of it. Also that might be included in the iOSD where you get warning and can land. Then you save your equipment and dont risk a big crash.

The best is still to make sure all wires is in good condition. The XT60 plus side must have got to negative to "melt" it so it short circuited. I just cant understand how this happened in the air unless a wire was loose or under pressure and then found some ground connection and then caused the unfortunate crash.

This is my opinion and its not giving "blame" or trying to say I know the answer. Its always no matter the reason sad when a crash happened.   I have had the S800 EVO and its been the most flaw less DJI I have had so far. I love my S900 but during a mishap in the A2 upgrade I had a small crash and Zenmuse break down (That DJI is fixing) but I loved the S800. Hope you get the S800 up in the air soon again!!
2014-12-19
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fabien
lvl.2

France
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Hi,

if you get a short on any of the XT 60 connector, please note that they are soldered on the frames and are linked together by a copper circuit. If you have a short circuit on the XT60 connector, the first thing that will blew up is the copper circuit on which the XT60 is connected.
A fuse will add nothing, unfortunately, except potential problems ( micro cuts, possible failure of the fuse filament..) .
The issue you have raised, which is a damaged cable on the PMU, is more an installation / maintenance failure from the operator / technician who handles the maintenance, rather than anything else.
This is my personal opinion and might not be the best, i admit
2015-1-8
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