Author Topic: Ho hum... Check your connections...  (Read 1667 times)

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DamonHD

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Ho hum... Check your connections...
« on: February 21, 2012, 10:05:24 AM »
I've cut my server energy consumption at home to run off-grid (solar), but it appears to have been running on wishful thinking rather than old-fashioned electricity for a while.

I was seeing rather deep dips in reported battery voltage when the server was busy that should be impossible.

So I stuck a note "check all connections" in my diary until I had something even less interesting to avoid doing.

I went round and systematically tightened every off-grid-related terminal connection inside the shed and house...  Even the ones that ... ahem ... didn't ... ahem ... need it.  Some had a bit more 'give' than I'd like, but what turned out the be the ground/0V connection of my server was basically floating around without the screw done up at all.

Not quite sure how I got away with that for so long, and tightening it properly did force a reboot.  Ooops.

Rgds

Damon
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dinges

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Re: Ho hum... Check your connections...
« Reply #1 on: February 21, 2012, 11:22:03 AM »
Could have been interesting to measure the voltage drop over the various contacts before tightening them. Especially at higher currents, a few milliohms quickly add up.

Good you have solved the problem, but I wouldn't have waited so long - in fact, I would have done it *immediately* once I became aware of the problem because of the possible fire hazard involved. Not sure what your system voltage is, but on a 48V system I've seen big (8 mm diameter pins, about 20 mm long) nearly completely vaporized away due to arcing.

Just because it's low voltage doesn't mean there's any less risk involved; it's just harder to electrocute yourself.... :D
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DamonHD

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Re: Ho hum... Check your connections...
« Reply #2 on: February 21, 2012, 11:51:02 AM »
You are of course right, and I should have looked sooner.

Since the server is measuring it's own supply then I think that it was getting something like the 1V--2V drop it was claiming at ~5W.  But I was indeed worried that I might have a higher-current loose connection upstream that could be a real hazard.

So I did the sensible thing... eventually.

(I have now tightened all the screw blocks with the exception of those at the other side of the house, outside, and a couple near one of the smaller batteries.)

Rgds

Damon

PS. I have an even worse confession, which is that the system may have survived because of signal grounding carrying some of the required current.  Don't look at me like that, please...
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