Solis fault code 2012 — Battery Communication Fail
What does fault code 2012 mean?
Fault code 2012 (Batt_Comms_Fail) means your Solis inverter has lost its digital communication link with the battery. Put simply, the inverter and battery are no longer “talking” to each other.
Common causes include:
A loose or disconnected CAN communication cable between the inverter and battery can break the digital link.
For example, a high-demand appliance like a heat pump or immersion heater momentarily exceeded the battery's safe output limit, triggering the Battery Management System (BMS) protection circuit.
The battery may have entered overtemperature, overcurrent, or another protection mode.
Work through the steps below in order. If the fault clears at any step, stop — no need to continue.
Step 1: Check the battery status
Go to your battery and check the following:
- Is it on? Look for any LEDs illuminated on the front panel.
- Check the power switch — ensure it is in the ON position. See Battery-Specific Controls below for the correct control for your battery model.
- Wake it up — if there are no lights at all, attempt to wake the battery using the start/power button. See Battery-Specific Controls below.
If there are no lights and the battery will not wake up, the BMS may have shut down due to a deep discharge rather than a communication fault. See our guide on what to do when a battery appears dead after a power cut before continuing.
Step 2: Check the communication cable
The CAN communication cable connects your battery to the inverter. It looks like an Ethernet (RJ45) cable.
- Locate the cable — trace it from the CAN port on the battery to the Battery Link port on the Solis inverter.
- Unplug the cable from both ends.
- Wait 10 seconds.
- Reconnect both ends firmly — you should feel a distinct click at each end.
- Wait 2–3 minutes to see if the fault clears.
Step 3: Full system restart
If the battery is on and the cable is seated correctly but the fault persists, perform a full system restart. Follow this exact order:
Shutdown
- Turn off the AC — switch off the Solar AC Isolator or the dedicated breaker at the consumer unit.
- Turn off the Solar (DC) — switch the DC Isolator (usually mounted near the inverter) to OFF.
- Turn off the battery — see Battery-Specific Controls below for the correct procedure for your model.
- Wait 60 seconds — wait for the inverter screen to go completely blank.
Startup (reverse order)
- Turn on the battery — see Battery-Specific Controls below. Wait for the LEDs to fully stabilise before continuing.
- Turn on the DC Isolator (Solar).
- Turn on the AC Isolator.
- Wait 2–5 minutes for the inverter to initialise and re-establish BMS communication.
Always shut down the inverter (AC isolator off) before turning off the battery, and always start the battery before turning the inverter back on. Reversing this order can cause the inverter to run briefly without a battery and generate additional fault codes. If you've accidentally reversed the order and need help, contact us.
Step 4: Check the DC breaker
Verify that the large DC breaker — the switch located between the battery and inverter — is firmly in the ON position. If it feels loose or will not stay ON, this indicates a hardware fault. Do not force it. Contact us to arrange a site visit.
Battery-specific controls
Different battery models have different power controls. Find your battery below for the correct procedure. Not sure which battery you have? Contact us and we'll help you identify it.
FoxESS — LV52
| Action | Control |
|---|---|
| Check status | LEDs on front panel; Power Switch (C) should be in the ON position |
| Wake up | No separate start button — if no LEDs, toggle Power Switch (C) OFF then ON |
| Turn off | Turn Power Switch (C) to OFF |
| Turn on | Turn Power Switch (C) to ON |
FoxESS — LV5200
The LV5200 has two separate controls — order is critical.
| Action | Control |
|---|---|
| Check status | LEDs on front panel; Power Switch (I) should be ON |
| Wake up | Ensure Power Switch (I) is ON, then press and hold Start Button (H) for 3–5 seconds until LEDs illuminate |
| Turn off | Hold Start Button (H) until the unit powers down, then turn Power Switch (I) to OFF |
| Turn on | Turn Power Switch (I) to ON first, then press Start Button (H) to activate the BMS |
Do not press Start Button (H) before Power Switch (I) is ON — the BMS will not activate.
WECO — 5K3 Dual / 5K3XP
These are the same unit. Both names refer to the same hardware.
| Action | Control |
|---|---|
| Check status | LEDs / display on front panel; power switch on side should be ON |
| Wake up | If no LEDs, toggle the side power switch OFF then ON |
| Turn off | Flip the power switch on the side of the unit to OFF |
| Turn on | Flip the power switch on the side of the unit to ON |
WECO — 5K3-EVO
The 5K3-EVO does not have a rocker switch on the side, it uses a front panel press-and-hold button. Not sure which model you have? Contact us and we'll help you identify it.
| Action | Control |
|---|---|
| Check status | LEDs on front panel |
| Wake up | Press and hold the power button on the front panel for 3–5 seconds until LEDs illuminate |
| Turn off | Press and hold the power button on the front panel until the unit shuts down |
| Turn on | Press and hold the power button on the front panel until the unit starts up |
Still having trouble?
If fault code 2012 persists after following all of the steps above, or you run into any issues along the way, please get in touch with your installation team at PureVolt Solar and we will be happy to help.
You might also find these related guides useful:
- All Solis fault codes explained — full reference table including codes 1055, 2015, and 2016.
- Battery appears dead after a power cut — if the battery is deeply discharged and won't communicate at all.
- Solis remote access setup — how to give us remote access to your inverter.