Sunsynk Datalogger Green Light Only & DNS Error Troubleshooting Guide

Reliable telemetry is vital for monitoring hybrid solar installations across South Africa, especially when coordinating battery charging strategies around scheduled load shedding. The Sunsynk Wi-Fi data logger stick (plugged into the bottom serial communication port of the inverter) communicates system parameters to cloud servers.

However, installers and homeowners frequently encounter a failure state where the data logger displays a single solid green LED light while remote monitoring shows the inverter as permanently offline. Alternatively, the monitoring portal logs a persistent DNS error.

This technical guide outlines the root causes of the green-light-only failure mode and provides the exact step-by-step restoration procedure using the logger's local access point interface.

1. Diagnostics: Why Does the Logger Show a Green Light Only?

The Sunsynk Wi-Fi data logger uses multi-colored LED status indicators to communicate its connection phase:

• Red LED (Power / Serial): Indicates 5V DC operating power from the inverter and active serial communications with the main control board.
• Green LED (Local Network): Indicates physical Wi-Fi radio connection to the local residential wireless router.
• Blue / Orange LED (Cloud Server): Indicates active TCP/IP socket connection and telemetry exchange with remote cloud servers.

```
+──────────────────────────────────────────────────────────────────────────+

+──────────────────────────────────────────────────────────────────────────+

+───────────────────────────+──────────────────────────────────────────────+

+───────────────────────────+──────────────────────────────────────────────+
```

The Static IP Address Collision

When the logger is showing a green light only, it has successfully negotiated a local wireless link with the local router, but cannot transmit packets out to the wider internet.

As explained in manufacturer technical support documentation:

When the data logger is first connected to the internet the static ip button is enabled. with this enabled the ip address will always stay the same and never change when your internet router is rebooted.

If this static IP address is not explicitly reserved at the router's DHCP reservation table, a classic IP address collision occurs:

1. The residential router reboots (frequently during load shedding power cycles).
2. The router dynamically assigns that same IP address to another household device (such as a smartphone, smart TV, or security camera).
3. When the data logger attempts to route packets, the duplicate address creates ARP table conflicts, preventing the logger from reaching the external internet gateway.

2. Step-by-Step Resolution: Clearing the Rogue Static IP

To resolve this issue, the static IP assignment must be cleared so the logger can negotiate a clean dynamic DHCP lease:

```
[ Step 1: Turn Off Internet Router Completely ]
│
▼
[ Step 2: Connect Smartphone / PC to Logger Hotspot (SSID: EAP-****) ]
│
▼
[ Step 3: Open Browser and Navigate to 10.10.10.1 ]
│
▼
[ Step 4: Untick "Use the following Static IP Address" and Click Save ]
│
▼
[ Step 5: Power On Internet Router to Restore Clean DHCP Lease ]
```

Execution Procedure

1. Power Down Local Router: Turn off your local internet router completely. This prevents your phone or laptop from automatically defaulting to the home network while configuring the logger.
2. Connect to Logger Hotspot:

• Access the Wi-Fi settings on your mobile phone or laptop.
• Locate the local Wi-Fi broadcast beginning with the prefix EAP- followed by the logger's serial number.
• Connect to this network and enter the default access point password.
• (Note: If the EAP- network does not appear in the available networks list, unplug the data logger from the bottom of the inverter, wait ten seconds, and plug it back in).

3. Access Configuration Interface:

• Once connected to the logger hotspot, open a standard web browser.
• In the URL address bar, enter the local gateway address: open an internet browser and search 10.10.10.1.

4. Disable Static IP Setting:

• When the data logger configuration interface loads, navigate to the network settings tab.
• Scroll down to locate the checkbox labeled Use the following static IP address.
• Untick the static IP box, leaving the logger in automatic DHCP mode, and click Save.

5. Restart Network: Turn your internet router back on. Within two to three minutes, the router assigns an unconflicted IP lease to the logger, and all status LEDs illuminate normally.

3. Resolving Persistent DNS & Serverset Errors

In certain installations, even with dynamic DHCP restored, the logger reports a DNS error because the local internet service provider (ISP) blocks or fails to resolve the cloud telemetry domain.

When this occurs, the destination server parameters must be updated directly via the internal CGI configuration script.

Serverset Parameter Configuration

1. Reconnect your mobile device or computer to the logger's EAP- wireless access point.
2. In your web browser, enter the specialized diagnostic command URL (confirm the correct regional cloud endpoint with local support, noting that ukiot.sunsynk.net is the default manufacturer UK server endpoint):
   ```
   http://10.10.10.1/serverset.cgi?addr=ukiot.sunsynk.net:51100
   ```
   As verified in manufacturer service instructions, targeting destination port 51100 establishes a raw TCP telemetry socket directly to the cloud ingest cluster.
3. Once the command returns a confirmation prompt, power cycle the data logger (or reboot the inverter from battery power) to restart the Wi-Fi stick.
4. The logger will re-initialize its network stack, resolve the updated ingest endpoint on port 51100, and immediately transition into active streaming mode.

4. Long-Term Wi-Fi Reliability Best Practices

To prevent future communication dropouts:

• DHCP Mac Reservation: In the home router's admin settings, bind the logger's MAC address to a permanent IP reservation high in the subnet (e.g., .240).
• 2.4 GHz Dedicated Band: Dataloggers operate exclusively on 2.4 GHz 802.11b/g/n networks. Ensure the router provides a separate 2.4 GHz SSID rather than combined band-steering, which can drop legacy IoT radios.
• Signal Strength: Verify that the signal level at the inverter location exceeds -70 dBm. If mounting inside an exterior metal enclosure, fit an external dipole antenna extension.

Summary Checklist

• Local home router powered down to isolate the data logger access point.
  
• Mobile device connected to EAP- hotspot and logged into 10.10.10.1.
  
• Static IP setting disabled to allow dynamic DHCP leasing without network collision.
  
• Serverset URL command executed targeting port 51100 if persistent DNS errors occur.
  
• All status LEDs verified active before concluding service.