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Deye F58: Battery BMS Communication Fault

Updated June 2026 · Reviewed for technical accuracy · ~3 min read

F58 means your Deye inverter has lost its data link with the battery's BMS (Battery Management System), so the two can no longer "talk". On a lithium battery this matters, because the inverter relies on the BMS to know when to charge and discharge safely. The most common cause is simple: a loose or wrong communication cable.

What usually causes F58, most common first

  • A loose comms cable. The RJ45 (network-style) cable between battery and inverter isn't fully clicked in at one end. By far the most common cause.
  • Wrong battery protocol or brand setting. The inverter is set to the wrong battery type, so the two speak "different languages".
  • Wrong port or DIP-switch address. The cable is in the wrong CAN/RS485 port, or the battery's address/DIP switches are set incorrectly (common with stacked batteries).
  • The battery is off or asleep. If the battery isn't powered on, there's nothing to communicate with.

The safe fix, step by step

Before you start You're only handling the low-voltage comms cable and settings, not battery power terminals. Don't touch the battery's main DC terminals.
  1. Check the battery is on. Make sure the battery is powered up and not in sleep or protection. Wake or switch it on if needed.
  2. Reseat the comms cable. Unplug the RJ45 communication cable at both ends and click it firmly back in until it latches. Inspect for a bent or broken clip.
  3. Confirm the right port. Check the cable is in the correct CAN (or RS485) port specified for your battery. Deye and the battery maker document which one.
  4. Set the correct battery protocol. In the inverter's battery settings, select the exact battery brand or protocol you have (for example the maker's named profile). The wrong one causes constant F58.
  5. Check addresses on stacked batteries. If you have more than one battery, verify the DIP-switch addresses follow the maker's sequence.
  6. Restart. Power-cycle the inverter (AC off, then DC isolator off, wait, restart) so it re-handshakes with the BMS.

Quick decision flowchart

F58 appears
↓ reseat cable, confirm port + protocol (steps 2 to 4)
✅ Comms restored, battery info shows again → solved.
❌ Still no comms after a known-good cable + correct settings → battery BMS or port fault.
↓
If it persists, contact your installer or battery maker. The BMS or comms port may be at fault.
When to call a professional If you've reseated a known-good cable, set the correct protocol and port, and F58 still won't clear, the issue is likely in the battery's BMS or the inverter's comms port. That needs your installer or the battery manufacturer.
About disabling the BMS alarm Deye lets you turn off "BMS_Err-Stop" in the LCD settings to silence the notification. Only consider this if your system is intentionally running in voltage mode without BMS comms. On a normal lithium setup you want BMS communication working, so don't just mute a real fault, because the BMS protects the battery.

Related Deye codes

F46, Battery defect F60, Battery over/under voltage F56, DC bus voltage low

FAQ

My battery still charges. Why does F58 matter?

Without BMS comms the inverter may fall back to voltage-based charging, which is less precise and can stress a lithium battery over time. Restore communication so the BMS can manage charge and discharge limits.

I changed nothing and F58 appeared. How?

Vibration, temperature cycling or a firmware update can loosen a marginal cable or reset a setting. Start with reseating the comms cable, it solves most "it just appeared" cases.

Which cable is the "comms cable"?

It's the thin network-style (RJ45) cable between the battery and the inverter's CAN/RS485 port, not the thick power cables on the battery terminals. Only handle the thin comms cable.

Sources

  • Deye Hybrid Inverter User Manual (F58 = "BMS communication fault"; BMS_Err-Stop setting).
  • Deye dealer technical references; common cause documented as a loose RJ45 comms connection.
⚠️ Safety disclaimer. Battery systems store large amounts of energy and can carry lethal voltage. This guide covers the low-voltage comms cable and settings only. Never touch battery power terminals or open equipment unless qualified. When in doubt, call a licensed installer or your battery manufacturer.