A little help from the Slave Skybox when using CTs?

A place to post images and descriptions of your OutBack Power System

Moderators: OutBack Moderator Team, OutBack

Post Reply
SHunsader
Forum Whiz
Posts: 48
Joined: Mon Feb 15, 2021 2:54 pm
My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

A little help from the Slave Skybox when using CTs?

Post by SHunsader »

Anyone out there running Skyboxes in a Master/Slave environment and have External Current Sensors installed?

Here's my setup: Pair of Skyboxes, each have their own 12 LG 340w panels, and each has its own 6.5kwh Discovery Lithium Iron Phosphate batteries. They're installed on a branch circuit off a 400A main panel, so a large chunk of power usage isn't being seen by the Skyboxes, until today (I've been up a total of 6 days, still tweaking). Per installation guidelines, I've installed the Current Transformers/Transducers (CTs) at the main panel, and the sense lines installed into the Master Skybox. (XCT L1 and XCT L2). I've tested and confirmed that the data I'm receiving to the Master Skybox is correct. I've asked tech support within the past 24 hours "How will the Slave know how much power to contribute to suppling power to offset the load?". His answer "They're linked together, the master shares this information with the slave, and it'll help out." I asked further "So if my installation see's an 8kw load, the slave will take 1/2 the load so that the Master doesn't have to foot all the work, right?". "Yes" was the response.

See attached. It doesn't appear that the Slave even knows that anything is happening.
I've checked to see that all parameters (other than Master/Slave assignment) are matching.

The left window is the Master and the right is the slave.

Hey, instead of the word "Skybox" shown in that pulldown window, wouldn't it be really "Cool" if the name of the system was put in there, so that it would synch up with the optics application? AND, even cooler, if one could choose either System, Master, or Slave (or just their names) so that one wouldn't have to run to each machine to configure? (and the System provides totals, and individuals show their contributions)

Any insight would be helpful. - Steve
Attachments
WheresTheHelp.jpg
SHunsader
Forum Whiz
Posts: 48
Joined: Mon Feb 15, 2021 2:54 pm
My RE system: Identically configured pair of Outback Skybox Systems each with 12 - LG 340 panels, and a Discovery 6.5kwh 48V battery, both running as Masters. External CT's, one using L1 CT input and the other using L2 CT input so as to help share load more evenly.
Location: SF Bay, California

Re: A little help from the Slave Skybox when using CTs?

Post by SHunsader »

Additional thought...If this is the way that the system is going to work (hoping that something isn't right, and that there's a 'fix'), I've considered taking the L2 sensor and bringing it over to the Slave system. I KNOW that this is NOT recommended, but at least the slave would be aware of perhaps 50% of the house load (assuming that electricians have adequately balanced the loads on the panels), AND could cover all the load on L2, while the Master covers the loads on L1.

I should probably run this by engineering at Outback to see the ramifications of doing so....But, I can see the advantages of doing so. The totals on the 2 systems should appear more balanced, and the Optics reporting should look much better as well. The way the system is running using external CTs implies that I'm AC Coupling (providing energy on the Load side of things) on the Master, and the Slave is behaving like a 'batteryless Grid Dependent Inverter (GD) supplying power through a breaker in the "Protected Load Panel", as described in the AC Coupling information in the Programming Guide on page 35.

Steve
Post Reply