LVTS-5220-HVX high-voltage battery - BMS alarm page on the battery touchscreen (LVTOPSUN BMS protection alarms)
LVTopsun Ahesion Flt error code
The BMS detected a main contactor or relay that has stuck closed (contact adhesion).
Likely causes
- Welded or stuck main contactor
- Contactor driven too often or under high inrush
- Contactor coil or driver fault
- Pre-charge circuit failure that damaged the contactor
Checks to run, in order
- 1Isolate the battery and check for voltage at the DC output with the contactor commanded open
- 2Check the event history for a preceding pre-charge fault
- 3Inspect the contactor for pitting or welding (HV-qualified personnel only)
- 4Check the contactor coil and driver circuit
Fixes
- Do not reconnect the battery to the inverter until the contactor is replaced
- Replace the contactor and verify open/close operation
- Check the pre-charge circuit before returning to service
When to escalate
A stuck contactor is a safety fault: stop, keep the battery isolated and have the distributor replace the contactor assembly.
Fix it with the right tools
Check the system around the fault before replacing parts: load, battery bank, PV string and commissioning settings. If you need a second opinion, send the code and your inverter model to our team.
Before you open the inverter
- Isolate both the AC and DC sides, then confirm the display is dead before touching terminals.
- Use insulated tools and one hand where possible. DC arcs do not self-extinguish like AC.
- If you see burnt terminals, swollen cells, leaking electrolyte or a burning smell, stop and escalate instead of resetting the fault.
Questions installers ask
What does LVTopsun Ahesion Flt mean?
The BMS detected a main contactor or relay that has stuck closed (contact adhesion).
How do I fix LVTopsun Ahesion Flt?
Do not reconnect the battery to the inverter until the contactor is replaced Replace the contactor and verify open/close operation Check the pre-charge circuit before returning to service
When should I escalate LVTopsun Ahesion Flt?
A stuck contactor is a safety fault: stop, keep the battery isolated and have the distributor replace the contactor assembly.
Can I reset LVTopsun Ahesion Flt myself?
Only after isolating the AC and DC sides and running the checks above. If LVTopsun Ahesion Flt returns immediately, stop resetting it and escalate; a repeating fault usually points to a real circuit, battery or hardware problem.
Which models show LVTopsun Ahesion Flt?
LVTopsun Ahesion Flt is documented for LVTS-5220-HVX high-voltage battery - BMS alarm page on the battery touchscreen (LVTOPSUN BMS protection alarms). Confirm the code on your own unit's display or manual before ordering parts.
More LVTopsun error codes
- LVTopsun Chg Bat Ov_VThe pack voltage rose above the BMS charge over-voltage limit.
- LVTopsun Chg Bat Ud_VPack voltage stayed below the BMS charge under-voltage limit while the pack was supposed to be charging.
- LVTopsun Chg Cell Ov_VCharging was stopped because a cell reached the BMS charge over-voltage limit.
- LVTopsun Chg Cell Ud_VA cell fell below the BMS charge under-voltage limit while the pack was being charged.
- LVTopsun Chg Diff_TThe temperature difference between BMS sensors exceeded the limit during charge.
- LVTopsun Chg Diff_VThe voltage difference between the highest and lowest cell exceeded the BMS limit during charge.
Guidance reviewed 17 October 2026 by the Mishka Energy installer team. Error codes vary by brand, model family and firmware; confirm against the manufacturer manual.
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