LVTS-5220-HVX high-voltage battery - BMS alarm page on the battery touchscreen (LVTOPSUN BMS protection alarms)
LVTopsun Prechg Flt error code
The pre-charge circuit did not bring the DC bus up as expected before the main contactor closed.
Likely causes
- Pre-charge resistor or contactor failed
- Short or low resistance on the DC bus or inverter input
- Inverter DC-link capacitance fault
- Control board timing fault
Checks to run, in order
- 1Isolate the battery and check the DC bus for a short
- 2Check the pre-charge resistor and contactor (HV-qualified personnel only)
- 3Disconnect the inverter and retry to see whether the fault follows the battery
- 4Check the event history for repeated pre-charge attempts
Fixes
- Do not bypass the pre-charge circuit
- Replace the failed pre-charge resistor or contactor
- Have the inverter DC input checked before reconnecting
When to escalate
If the pre-charge fault repeats with the inverter disconnected, keep the battery isolated and have the distributor service the contactor box.
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 Prechg Flt mean?
The pre-charge circuit did not bring the DC bus up as expected before the main contactor closed.
How do I fix LVTopsun Prechg Flt?
Do not bypass the pre-charge circuit Replace the failed pre-charge resistor or contactor Have the inverter DC input checked before reconnecting
When should I escalate LVTopsun Prechg Flt?
If the pre-charge fault repeats with the inverter disconnected, keep the battery isolated and have the distributor service the contactor box.
Can I reset LVTopsun Prechg Flt myself?
Only after isolating the AC and DC sides and running the checks above. If LVTopsun Prechg 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 Prechg Flt?
LVTopsun Prechg 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 Ahesion FltThe BMS detected a main contactor or relay that has stuck closed (contact adhesion).
- 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.
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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