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Old Dec 08, 2014, 08:38 PM
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United States, MA
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Wow, good thing you checked it! I don't know if anything involving the ribbon cable could cause that. But I definitely wouldn't run anything off it until you get the issue resolved.
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Old Dec 08, 2014, 08:57 PM
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United States, FL, Orlando
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Are you using a cheap multimeter? If your multimeter doesn't do AC RMS measurements, it can act wacky when connected to a DC source. I have heard that they can read 2X the DC voltage but sometimes they do other odd things instead.

Edit: More info: http://electronics.stackexchange.com/a/31152
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Old Dec 08, 2014, 09:07 PM
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Interesting reading. So maybe try measuring a LiPo (or some other battery, preferably ~12V) in AC mode. That's output that you know is DC, with no AC component.

Edit: I just checked my supply again, with a cheap Harbor Freight multimeter. Set to AC, I got 26.9V. Roughly twice the DC voltage, which is around 12.7V.

Yesterday, when I measured 0.003V in AC mode, I was using my Innova 3320 meter. Nothing fancy, but better than my Harbor Freight one.
http://www.amazon.com/INNOVA-3320-Au.../dp/B000EVYGZA

But this helps make CerealKiller159's point, that the meter you're using plays a role in what you measure. Thanks for the heads up on that!
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Last edited by RedOctobyr; Dec 08, 2014 at 09:29 PM.
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Old Dec 08, 2014, 09:51 PM
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yes i had just come to the same conclusion: i think it's my cheap multimeter.

My dad has some fancy ones so I'll use his to confirm next time I visit him. The way I understand it, it shouldn't matter if I mix up positive / negative prongs when measuring AC voltage with my multimeter. However my multimeter is only picking up the AC voltage if I use black prong on negative/ground and red prong on postive, if I reverse this then no voltage is measured. So this leads me to believe it's probably just DC voltage that is making my multimeter go crazy.

Like I said though, I'll confirm this Christmas though when I go visit my dad.
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Old Dec 09, 2014, 07:47 AM
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If you need to use the supply sooner, measure a battery. A 3S LiPo or car battery would be perfect. If they also show ~26V AC (which is not possible), then you know it's the meter.
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Old Dec 18, 2014, 10:20 AM
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Joined Dec 2014
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Hello!
First off - I gotta say thanks to rchelijc, feathermerchant, chemie, and everyone else for the fantastic information here. I read all 1500 posts, good stuff and thanks for sharing experiences. The 3 i mention by name helped me considerably.
I have a build that I've gone a bit overboard with switches/LEDs and such (just cuz i can as stated in an earlier post). I am assembling a parallel system, 12v, with 90A out.
The question is the binding posts, or connection coming off the 12v rail. What I have is a panel with connectors, switches, meters, etc and want to have the binding posts there too. I see many of the builds with cases having binding posts, where did you get them for such high amperage? I am not looking for 90A connectors, more like 40A and the best I've come up with is 30A. Something that could mount to a panel, not a dangling cord....
Should I look at a different connector like power poles or something? ( I wanted to outputs that could handle 45A)

Thoughts/Advice?
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Old Dec 18, 2014, 11:03 AM
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United States, MA
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45A will likely start warming up PowerPoles, based on what I've seen with mine.

You might consider EC5, or a similar large bullet connector, though they'd be tougher to panel-mount.
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Old Dec 18, 2014, 11:55 AM
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Quote:
Originally Posted by Dr. Build View Post
I see many of the builds with cases having binding posts, where did you get them for such high amperage? I am not looking for 90A connectors, more like 40A and the best I've come up with is 30A.
The '30A' connectors that you've found will work just fine. I've used '30A' 4mm panel mount binding posts at 50A+ for extended periods of time without issue. Remember, they're not fuses so the ratings are not particularly meaningful and many if not most are very conservatively rated.

Simply attach them with adequate gauge wire (10 or 12 AWG) or direct connect to the terminals with ample solder (800F iron would be helpful here). Yes, they get warm but nowhere near the solder reflow or plastic melting temperatures.
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Old Dec 18, 2014, 03:01 PM
Pilot in training
Joined Dec 2014
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Thanks - RedOctobyr and mrforsyth
I have no experience with the power pole connectors and they are spendy to "try." good info there. I'll pick up a few of the 30A binding post versions...
I do have electronic experience so I've got the wiring set at 10awg from each PSU (at like 10" length) and joined to a bus (big metal plate, plenty o metal for amperes). I didn't think about measuring the sizes of that binding post. Thanks!
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Last edited by Dr. Build; Dec 18, 2014 at 03:02 PM. Reason: staement unclear
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