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Dual Display Harness (Read 150 times)
Oct 26th, 2018 at 9:24am

Bob Reinhardt   Offline
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I love flying!
College Station, Texas

Gender: male
Posts: 28
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There is a question at the end...

A while back I asked about "mirroring" one display to another and learned each display needs input from whatever sources are being fed into it.  If this were an initial build I'd have simple run two set of the needed wires.  As it is to trace back to the sources would entail a deconstruction of the aircraft.  So I built a Y cable into which the current display cable is plugged and the two legs of the Y each have an appropriate D37 to plug into the two displays.  Being mindful that the back up battery wires could not go to two batteries, those (2 & 23) are route external to the connector at the co-pilot display and connect to a separate back-up battery.

Once I brought the software up to date on the display that had not been used in a few years and reconfigured the system, everything looks fine.

In constructing the Y I purchased a second D37 wiring harness, and built the common end myself.  Where I merged two leads into one I soldered the two 22 gauge wires to a piece of 20gauge.

In soldering the two different gauge wires together I made mental note to check the total current load.  The original set up with one 1000T could draw between 2.86 and 3.86 amps in my set-up depending on whether the battery was charging.  Adding the 7' display (a less efficient version) added and equal amount. So totals between 5.66 and 7.66 depending on whether 0,1 or 2 batteries were being charged. 

I believe 22 gauge wire has an ampacity of 5amp bundled and 7 amps unbundled. Leaving the second back-up battery out of the system would at leas get the requirements between the two.  However, (and here is the question),
I also am aware that the display has two 12 volt input sources (pins 1 & 20).  Where I lack the knowledge is whether these two wires constitute two paths (each of which could conduct 5-7 amps).  There is no doubt they represents two separate baths back to the +electronics buss, but what happens inside the display? If they continue as separate "circuits" in the display, it might not help with my issue.

Thanks, so it took so much explanation.
 
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Reply #1 - Oct 26th, 2018 at 12:34pm

dlloyd   Offline
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Locust, NC

Gender: male
Posts: 111
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Pins 1 & 20 are the same power path.  The two pins are used as one may not carry the load.
 
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Reply #2 - Oct 26th, 2018 at 6:12pm

Bob Reinhardt   Offline
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I love flying!
College Station, Texas

Gender: male
Posts: 28
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Many thanks, that tells me my wiring should be fine since two 22 gauge wires can handle more than enough.
 
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