- Solar and energy
- Solar inverter
CAN Fail
Solis CAN Fail on hybrid inverter: battery CAN link lost
Risk level
Medium
Proceed carefully and stop if the check is unclear.
Urgency
Medium
Quick answer
Solis alarm CAN Fail (also shown as Batt_Comm_FAIL or CAN_Comm_FAIL) means the hybrid inverter cannot communicate over the CAN bus with the battery BMS. Check the battery LEDs and SolisCloud without touching terminals, and call your installer if the alarm persists.
Safety first
Stop and check this first
- The Solis S6-EH1P manual warns that surfaces can be hot and requires turning off the inverter and waiting 5 minutes before service; disconnecting the battery to measure terminal voltage with a multimeter must only be done by a qualified professional.
Safe checks you can perform
- Check that the red LED on the battery is not shining or flashing
- Check BMS Voltage and Battery Voltage in SolisCloud
- Read the RJ45 cable label and restart after a 5-minute wait
Leave these tasks to a qualified professional
- Do not attempt this professional task: CAN communication cable replacement or pinout correction
- Do not attempt this professional task: Physical battery output voltage measurement and model setting check
What a technician must be able to justify
Technician visit
These are the steps they must carry out and show you. Tick them as they work: if steps are skipped, do not accept a part swap.
These are not instructions for opening or handling the equipment yourself. They are the checks that should support a technical conclusion.
CAN communication cable replacement or pinout correction
What they doThe installer verifies that the cable is plugged into the CAN port on both the battery and the Solis inverter and, on Pylontech US2000C, US3000C or US5000 batteries, replaces it with the updated WIOSCAN30RJ1 cable or alters the pinout to match Solis's diagram.
They must show youthe cable connected to the CAN ports on both units, the cable part number or pinout, and active BMS data on screen.
In writingthe RJ45 cable version fitted (such as WIOSCAN30RJ1) and the ports verified on battery and inverter.
Physical battery output voltage measurement and model setting check
What they doThe technician disconnects the battery from the inverter, measures the voltage at the battery terminals with a multimeter, compares it with Battery Voltage in SolisCloud, and confirms the battery brand selection in the inverter menu.
They must show youthe multimeter reading at the battery terminals alongside the SolisCloud BMS Voltage and Battery Voltage readings.
In writingthe measured terminal voltage, the SolisCloud voltage readings and the selected battery model setting.
Before accepting a part or repair
Nothing has been shown yet. Do not accept a part swap based on the code alone.
Follow these steps
Note: Follow the documented order. An error code identifies the affected system, but it does not prove by itself which part has failed.
Check that the red LED on the battery is not shining or flashing
- Who:
- you, looking at the battery front panel from outside without disconnecting any cables.
- How:
- follow the Solis Service Center check and look at the battery status lights to confirm the red LED is neither shining nor flashing and the LEDs are green.
- Result that matters:
- finding out whether the battery is too empty to run its BMS communication.
- If the red LED on the battery is shining or flashing:
- Solis states the battery is too empty to work and needs charging with an external charger by a professional until the LEDs return to green.
- If the battery LEDs are green:
- the battery has charge and the issue lies in the CAN link or settings, so check the voltages in SolisCloud next.
- Evidence to keep:
- a photo of the battery indicator LEDs and the alarm text on the Solis inverter screen.
Evidence: Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
Check BMS Voltage and Battery Voltage in SolisCloud
- Who:
- you, using the SolisCloud app or web portal.
- How:
- open SolisCloud, go to the battery monitoring section and select both BMS Voltage and Battery Voltage to see whether the system detects the battery and whether No Battery is also logged.
- Result that matters:
- seeing whether the inverter reads terminal voltage while BMS Voltage is missing due to the CAN failure.
- If BMS Voltage is missing or significantly lower than expected:
- this matches the CAN communication issue described by Solis.
- If both voltages match and the alarm has cleared:
- note the time in case the drop was brief.
- Evidence to keep:
- a SolisCloud screenshot with both BMS Voltage and Battery Voltage plotted.
Evidence: Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
Read the RJ45 cable label and restart after a 5-minute wait
- Who:
- you, checking the outer label on the data cable without touching DC power terminals.
- How:
- look for a serial label on the RJ45 cable (WIOSCAN30RJ1 new version vs WIOSCAN35RJ3 old version); if your installer showed you how to power-cycle the inverter, Table 7.1's note says to turn off the inverter and wait 5 minutes before restarting.
- Result that matters:
- ruling out a temporary latch-up and identifying whether an older Pylontech cable is fitted.
- If the cable is marked WIOSCAN35RJ3 or the alarm remains after a 5-minute restart:
- contact your installer or distributor.
- If communication resumes after the 5-minute restart:
- confirm in SolisCloud that BMS telemetry stays stable.
- Evidence to keep:
- a photo of the RJ45 cable label, the Solis inverter serial number and the installation date.
Evidence: User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS Version 1.3, Release Date: 04,2026 · Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
Still not solved
If the error persists, stop here. See what the technician must do and show you.
Where this code applies
A code is meaningful only inside the right product and version context.
Primary scope
- System
- Solar and energy
- Brand
- Solis (Ginlong)
- Product type
- Solar inverter
Known code variants
- Batt_Comm_FAIL Solis
- CAN_Comm_FAIL Solis
- fallo comunicación CAN batería Solis S6-EH1P
- Solis Batt_Comm_FAIL
- Solis CAN Fail
- Solis CAN_Comm_FAIL
- Solis híbrido CAN Fail No Battery
- Solis hybrid battery CAN communication failure
- Solis S6-EH1P CAN Fail
What it means
In the Solis S6-EH1P(3-8)K-L-PLUS hybrid inverter user manual (Version 1.3, April 2026, Table 7.1) and the Solis Service Center article on Pylontech US2000C, US3000C and US5000 batteries (updated 2025-03-05), CAN Fail (or 'Batt_Comm_FAIL', previously 'CAN_Comm_FAIL') indicates a communication failure on the Controller Area Network (CAN) bus between the inverter and the battery's Battery Management System (BMS), which can also trigger a follow-up 'No Battery' alarm. Solis links it to a faulty cable, wrong port connection, an incompatible RJ45 cable version, or a powered-off or deeply discharged battery. The code alone never proves the inverter or battery is defective.
Warnings and stop conditions
- Highsource verified
The Solis S6-EH1P manual warns that surfaces can be hot and requires turning off the inverter and waiting 5 minutes before service; disconnecting the battery to measure terminal voltage with a multimeter must only be done by a qualified professional.
Evidence: User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS Version 1.3, Release Date: 04,2026 · Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
Symptoms and causes
Probable causes · in order
- Damaged CAN cable or plug inserted into the wrong portCommon
Table 7.1 of the S6-EH1P manual explains that CAN Fail occurs when the cable is in poor condition or is not plugged into the CAN port on both the battery and the inverter.
Evidence: User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS Version 1.3, Release Date: 04,2026
- Outdated or incompatible RJ45 battery communication cableCommon
Solis notes that some batteries require a special manufacturer cable; on Pylontech US2000C, US3000C and US5000 units, the older WIOSCAN35RJ3 cable must be replaced with the updated WIOSCAN30RJ1 cable or re-pinned.
Evidence: User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS Version 1.3, Release Date: 04,2026 · Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
- Battery powered off, deeply discharged or wrong battery model setPossible
The Solis Service Center article explains that a powered-off battery, a battery with its red LED shining or flashing because it is too empty, or wrong inverter battery settings will prevent BMS detection.
Evidence: User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS Version 1.3, Release Date: 04,2026 · Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
Virtual technician
Does CAN Fail still appear after these checks?
Answer a few questions to narrow down the likely cause and the safest next action. Guidance only - it never replaces a professional.
Sources and technical references
- 1
User Manual for S6 Series Hybrid Inverter S6-EH1P(3-8)K-L-PLUS Version 1.3, Release Date: 04,2026
Ginlong Technologies Co., Ltd. (Solis) · 2026 · manual
- 2
Pylon US2000C/US3000C/US5000 Battery - Batt_Comm_FAIL - No Battery
Ginlong (Ningbo) Technologies Co., Ltd. (Solis Service Center) · 2025 · official_doc
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