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Unread 11-11-2017, 06:01 PM
david1389 david1389 is offline
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Extra dc power connections?

New to FRC and am assisting with electrical. We have run out of connections on the PDP and we need 2 or 3 more, for a Raspberry pi, a camera and a ring light. Is there a preferred/recommended device for create a few more power outlets, e.g. a kind of sub-panel that isn't too large or expensive? I don't believe we need separate fuses since these are low power devices that should be able to share the fuse on the PDP. Thanks
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Unread 11-11-2017, 06:14 PM
MuskieProgramme MuskieProgramme is offline
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Re: Extra dc power connections?

I would not connect a raspberry pi to the PDP. For one thing, the 12 volts will undoubtedly destroy it.

Instead, I would connect it to a Voltage Regulator Module, on one of the 5V 2A ports.
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Unread 11-11-2017, 06:24 PM
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Re: Extra dc power connections?

I was trying to keep the question simple and left out the part about using a power converter for the Pi.
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Unread 11-11-2017, 06:27 PM
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Re: Extra dc power connections?

Also [out of scope of question]: the Pi 3 recommended current is 2.5A and the converter is rated at 2A.

Anyway, the core of the question is about "sharing" a single output of the PDP to 2 or 3 devices in a manner that is clean, reliable and not too expensive.

Thanks.
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Unread 11-11-2017, 06:48 PM
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Re: Extra dc power connections?

Do you, by any chance, have the old 12V to 5V converters used for the router before 2015? You can hook one of those up to a PDP slot and run the Pi off of that. As for breaking up a PDP port, you could use some multi-pole lever nuts.
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Unread 11-11-2017, 06:53 PM
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Re: Extra dc power connections?

The Wago devices look cool, thanks.
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Unread 11-11-2017, 07:20 PM
MuskieProgramme MuskieProgramme is offline
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Re: Extra dc power connections?

The pi will normally draw around 700 mA. The 2.5A rating assumes the pi is powering additional devices which draw significant current.
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Unread 11-11-2017, 07:28 PM
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Re: Extra dc power connections?

From a standpoint of being legal with the rules of recent years [usual caveat that they may change], each PDP circuit may be used for any one of the following, (reordered from R56):
  • one motor controller
  • one spike relay
  • one PCM powering a compressor
  • up to three VRMs
  • an unlimited number of fans
  • a CUSTOM CIRCUIT
I understand you are asking about custom circuits, which is essentially anything that doesn't fall under the first five categories or the components they control. The custom circuit may have multiple components/loads, but you must have a single wire in each WAGO on the PDP (R53), and do your branching junction away from the PDP (permitted by R56). Reading the whole electrical section of the latest rules is always in order especially if you're going into new territory. In particular, you want to check out the blue box under R56, allowing a second tier of fuses/breakers. Something like this may be what you're looking for - hit your local auto or marine parts shop. If you aren't looking for fuses, something simpler like crimp splices (again auto parts shop) or these are appropriate.
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Last edited by GeeTwo : 11-11-2017 at 07:35 PM. Reason: added last two sentences
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