Elk Databus, voltage loss, series, parallel runs.

[archstenton]

Finally getting to the point of hooking up the M1 so doubtful this is my last thread.
 
Went ahead and ran Cat6 between the data bus pieces.  Although,due to whatever, just daisy chained it the cables, not home run.
 
This is the approximate layout
 
M1<---15 ft--->KP2<----5 ft---->M1XRF2H<----40 ft--->M1XIN
 
Since I got the 8 conductors, figure will double up the data.
 
But was wondering should I wire maybe the M1XIN for power in parallel with the last 2 spare wires?  In the M1 manual for home runs, it mentions don't daisy chain the power due to unnecessary voltage loss.  So if I have a spare pair, does it make sense to do some combo of parallel power run with them?

 

[RAL]

Fortunately, your wire lengths are fairly short.  The current draw for all  3 of the devices shouldn't be more than  0.22 A.   The far end wire resistance of the Cat6 cable will be about 2 ohms if you use just a single pair, giving you a worst case voltage drop of 0.4V.  (That's really an over statement, calculated as if the far end device, the M1XIN, was drawing all the current).   
 
I'd use 1 pair of conductors for the Data A and B signals, and use the other 3 pairs for power, on all three segments.  That will reduce the voltage drop by a factor of 3.  Since you didn't home run the cables, you don't need to use a second pair of wires for Data A and B.

 

[archstenton]

Thanks, didn't think of it that way.