Is the Sunsynk SYNK-SG04LP1-SM2 SYNK-5K-SG04LP1-SM2 compatible with the Sunsynk CHNT DTSU666 (3ph + CTs)?

Yes — listed by the manufacturer.

The manufacturer's published pairing data lists these together.

Manufacturer's compatibility listListed together in the manufacturer's published pairing data. A cited document reference is being added as datasheets are processed.

Pairing details

Both products

Design a system with this pair