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Diagram for communication connections 2 Exparts


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Hi All,

I'm a newbie here.  I did a search but cannot find a diagram of the communication connections between 2 x 5KVA Exparts/RCTs  in parallel.

I appreciate any help in this regard.

Thanks

Cassie

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I found on the internet a diagram as well as  a picture of the parallel kit.  

However it shows the Red & Black cable as twisted.  But the Red & Black cables which I got with the Axparts are not twisted (please see the attached photo).

Is the connection diagram correct?

Must the Red&Black wires be twisted?

Thanks
Cassie

Red&black cable.jpg

Internet Red&Black twisted.png

Internet_communication diagram.png

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2 hours ago, Youda said:

This is how the cable should look. Red and Black wires are NOT cross-connected. Just the cable itself is "twisted" as a form of shielding.

http://www.easunpower.com/upLoad/product/month_1809/201809121817277027.jpg

Thanks Youda,

from the illustration, I got from the Internet, the Red & Black appears to be cross-connected.  This was confusing as the Red&Black cable, from the Inverter packaging, was not cross-connected. 

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9 hours ago, Cassie said:

the illustration, I got from the Internet, the Red & Black appears to be cross-connected.

It's a confusing diagram, but they are not actually cross connected in that diagram. If you mentally rotate the right connector to end up beside the left connector and facing the same way, you'll see that the top pin connects to the top pin. 

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Posted (edited)
7 hours ago, Coulomb said:

It's a confusing diagram, but they are not actually cross connected in that diagram. If you mentally rotate the right connector to end up beside the left connector and facing the same way, you'll see that the top pin connects to the top pin. 

Thank you Coulomb,

Yes I actually noticed afterwards that they are not cross connected when I looked carefully at the drawing.  

I have another question, maybe you can give me either assurance or advice to make changes to my installation.  I used 2 mild steel bolts and nuts to act as "busbars" for my positive and negative cables from my Pylontech to the inverters via the fuses.  I have a nut in between evey lug to create space between the cables.   My worry now is that mild steel is only 12% conductive, compared to copper.  Will it influence my system negatively?  Must I replace it with 2 true proper copper buzz bars?

Or is it OK to use it.  It will take major work to change it, I must say.

Thank so much for your support.

Regards

Cassie

Edited by Cassie
spelling mistake
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1 hour ago, Cassie said:

I have a nut in between every lug to create space between the cables.   My worry now is that mild steel is only 12% conductive, compared to copper.  Will it influence my system negatively?

You should change that; inverters can readily draw something like 100 A each, and at that sort of current, every micro-ohm counts. The resultant voltage drops will cause losses but also will affect battery charging; the battery could be under-charged as a result, reducing its life.

You might be able to rearrange the lugs so that the lugs are touching each other, with no nuts or even washers between them. It then doesn't matter that you have a steel bolt, little of the current will flow through the bolt, it will all be copper lug to copper lug. Use a spring washer to keep the lugs in contact. Have the lugs arrive at different angles to keep them separate.

Hopefully that won't require too much re-arrangement.

 

 

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Hi Coulomb,

thanks again, for you detailed answer and support.
 I think what I’m going to do is to replace either the nuts in between with copper nuts/copper washers, if I can get some in this little town where we’re living.  Or to squeeze the lugs in together which might be difficult with the amount of space I have and the amount of play I have  on the cables. The lugs squeezed in together will be the better option I suppose ?

Regards

Cassie

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14 minutes ago, Cassie said:

The lugs squeezed in together will be the better option I suppose ?

I believe so. Lugs are flat and are designed to carry current, nuts including copper ones, are not.

Edit: However, using copper nuts would be far better than what you have now.

Edited by Coulomb
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On 2020/06/11 at 2:39 PM, Coulomb said:

I believe so. Lugs are flat and are designed to carry current, nuts including copper ones, are not.

Edit: However, using copper nuts would be far better than what you have now.

Hi Coulomb,  

I managed to squeezed all the lugs together.  It was a bit difficult;  I like to solder the lugs after crimping, the solder tends to run inside the cable for a short distance and that makes the cable hard to bend - I had to put the last 2 cables into a vice and used a 15mm pipe over the lugs to give them a bend so that they can arrive at an angle and flat onto the previous lugs.  (The first 2 lugs on each bolt are back to back, thus straight but then the last one at an angle to get it flat on the previous lugs).

Below a photo of the end result - I'm not too happy with the bends but as long as they are 100% functional - they are covered in a 100 x 40 trunking box.

Lugs-Connections.png

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7 hours ago, Cassie said:

I like to solder the lugs after crimping, the solder tends to run inside the cable for a short distance and that makes the cable hard to bend

That wicking of the solder is why it's not recommended to solder wires after crimping. The point where the solder stops becomes a stress point if the wires move. But it should be OK in a stationary application.

7 hours ago, Cassie said:

as long as they are 100% functional - they are covered in a 100 x 40 trunking box.

If designing from scratch, I'd suggest leaving more gap between the bolts; less chance of a tool bringing the gap. But since it will be covered, that should be fine.

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On 2020/06/13 at 2:46 AM, Coulomb said:

That wicking of the solder is why it's not recommended to solder wires after crimping. The point where the solder stops becomes a stress point if the wires move. But it should be OK in a stationary application.

If designing from scratch, I'd suggest leaving more gap between the bolts; less chance of a tool bringing the gap. But since it will be covered, that should be fine.

Thanks Coulomb,

I'm nearly finished, at the moment building a steel bracket to host 2x Pylontechs US3000's vertical wall mounted (buttons up) - due to space restrictions - in the kitchen's wash-up area below the main switchboard.  I'll post a photo when I'm done.

Thanks for all the advice.

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