Technical Support

What would be the process to check and observe if the CT coil install is correct and free of interference?

I'm trying to understand why my system sometimes exports power to grid despite Zero export being set at 20W as well as why it sometimes draws power from the grid when it should be using the battery.

What does grid status 0, 1 and 2 mean?

As per manual, orientation of the CT coil is correct (not swapped), but on a few occasions I've noticed the device data on solarman shows grid status flip flopping. What I've observed:

- Solarman app device history shows grid stats bouncing between status 0 and 2 (see screenshot below). What does this mean? At the time the grid voltage and frequency were within spec for most of the day. - Sometimes a few W is exported despite having Zero Export set.

- Sometimes a lot of W is pulled from grid when SoC on battery is good and the load well within limits. E.g. with a heat controlled 1700W kettle, it switches it's relay on and off a few times as it tapers off to get to the preset temperature. This 1700W on-off-on-off-on-off load pattern gets the inverter panel showing something like ~800W drawn from grid and ~900W drawn from battery (but variable over time) suggesting it's using grid unnecessarily as battery SoC is well within limits set (see screenshots below).

I've read shielding helps a bit, but the most important aspect of a CT cable is it needs to be twisted to avoid 50Hz interference and should be 18 to 22AWG (0.32mm2 / 0.65mm diameter).

- In theory, using CAT 5e 24AWG (~0.20mm2) and combining/splicing to 2 pairs for each CT wire (2x 0.20mm2 = 0.40mm2 > 0.32mm2) - i.e. using all 4 pairs in the CAT cable should do the trick?

- CAT6A with shielding would likely help more? (seen a another forum post here were that was done)

- I searched and could not find any companies in South Africa that supply twised cables with 0.32mm2 / 22AWG or larger size.

Context: - The CT cable runs about 7m in same conduit with the AC cables to main DB. (Yes, this is far from the ideal of routing the CT cable separately and away from the AC cables, but the conduit had to be shared and I wanted to avoid extra chasing work which would require lifting up floors or replastering, etc.)

- When my installer arrived, they only offered to use flat twinpair (not twisted pair) electrical cable or a CAT5e cable to extend the CT coil. I forced the choice to Cat5e since I thought flat winpair would be worse.

- Noticed that where installer had the CT coil, the main incoming supply cable bends a bit as it passes through the coil. Should I have that made 100% straight?

This week so far (note, we did have grid/supply issues on tuesday, and briefly thursday when the utility was doing work, but not the whole week!):

Yesterday (friday, and we had no supply issues)

On the solarman website, one can get better graphs overlaid.

Here's an example from Tue 17:10:10 when I'm exporting over -200W when I have zero export set and should be using +20W?

And here's an example where despite having limits set to 40% battery and 4800W with SOC up at 86% (> 40% limit), 952W drawn from grid (Meter) and 1572W from battery to supply 2502W (< 4800W limit). Why was grid used? Why not all 2502W from battery?

Related: - https://ctlsys.com/support/current-transformer-ct-wire-extension/

- https://www.sunsynk.org/forum/techical-support/maximum-length-of-ct-coil-cable

- https://www.sunsynk.org/forum/techical-support/ct-readings

- https://www.sunsynk.org/forum/techical-support/connecting-a-ct-coil-update

P.S. in case there's a concern my grid supply is too unstable/an issue, here's the week. Yes 2 outages, but not at the time of the examples in the issues shown above. Grid V (left axis) and Hz (right axis):