Power bridge MK II

Well, there’s been an accident. Quite a serious one. When we’ve been trying to test some higher powers for our motors – signal cables to our ESCs burned out.

Interestingly, as you can see on pictures above, only the ground cable combusted. The signal cable seem to be ok.

I’ve obviously started thinking where things went wrong and as tried to measure current going trough our power bridge we noticed that part of it burned out / short-cut-ed as well (unfortunately I haven’t taken a picture). Discussing all that story with Risa and Bernard they made me to draw them a diagram first.

Not sure it it makes any sense, but battery is in a bottom left corner and current is distributed through our Power Bridge to both ESCs, which then control Motors. There are also signal cables going between ESCs and our brain-Arduino.

As wrote above, showing this to Risa and Bernard, I’ve ended up with following update.

There’s been probably lots of current running through a whole system, which was too much for our PCB-based Power Bridge. The big red X shows where our power connector disconnected from PCB and caused a current redirection. Instead of going through the wire “7” it released power through other grounded cables 3->5. And as those were too thin they … combusted.

So the first step to tackle this was a complete rewiring of all high-power cables (25A).

Cabling before on the left, new one on the right

Second part of the plan was our power bridge re-design. Sebi cut off all the PCB material and soldered in some serious copper wires.

It all obviously didn’t fit in our old case, so bit of printing was needed as well.

And 3 weeks later we are where we’ve started! 😀 Hopefully it will work out now.

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