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FAQ – Lithium System Winterization Battery disconnection and reconnection procedures (Victron Quattro – Lynx BMS / VE.Bus BMS – Orion XS)

This procedure applies to GRP boats equipped with:

  • Victron Quattro / Multi inverter-chargers
  • Lithium batteries
  • Either Lynx BMS (Lynx BMS / Lynx BMS NG) or VE.Bus BMS
  • Possibly Orion XS DC-DC converters

The procedures below are designed to:

  • avoid damage to inverter input capacitors,
  • avoid damage to Orion XS DC-DC converters,
  • ensure safe and repeatable winterization and recommissioning.

BEFORE ANY OPERATION (DISCONNECT OR RECONNECT)

Always verify:

  • All AC sources are OFF (shore power disconnected, generator stopped)
  • All Quattro inverters are OFF
  • All battery switches are OFF
  • No high DC loads are active

PART 1 – DISCONNECTING THE SYSTEM (WINTERIZATION)

Applicable to both Lynx BMS and VE.Bus BMS systems

Disconnection sequence

  1. Switch all battery switches to OFF
  2. Disconnect battery positive
  3. Disconnect battery negative

Notes

  • This sequence ensures the system is never left with a floating negative while positive is still present.
  • Orion XS units are safely de-energized when battery switches are OFF.

Lithium battery State of Charge (SOC) for winter storage

For lithium batteries, do not store fully charged or fully discharged.

Recommended SOC for storage

  • Ideal range: 40 % to 60 % SOC
  • Acceptable short-term range: 30 % to 70 %
  • Avoid:
    • Long-term storage above 80 % SOC
    • Storage below 20 % SOC

Additional recommendations

  • If possible, check SOC once during winter and recharge slightly if SOC drops below ~30 %
  • Store batteries in a dry environment
  • Avoid prolonged exposure to temperatures below 0 °C or above 40 °C
  • Never charge lithium batteries if cell temperature is below the manufacturer’s minimum charge temperature

PART 2 – RECONNECTING THE SYSTEM (DE-WINTERIZATION)

Initial checks (mandatory)

Before reconnecting:

  • All battery switches remain OFF
  • All AC sources remain OFF
  • All Quattro inverters remain OFF

1) Systems with Lynx BMS (Lynx BMS / Lynx BMS NG)

Description

The Lynx BMS manages the battery connection via internal contactors and provides controlled reconnection of the DC system, including inrush current management.

Reconnection procedure

  1. Battery switches OFF
  2. Connect battery negative first
  3. Connect battery positive
  4. Switch battery switches ON
  5. The Lynx BMS closes its internal contactors and brings the system online in a controlled manner

Important points

  • No external pre-charge resistor is required
  • The Lynx BMS protects Quattro inverter input capacitors
  • Normal operation resumes once contactors are closed

2) Systems with VE.Bus BMS (older lithium systems)

Description

VE.Bus BMS systems do not provide DC bus pre-charge.

Reconnection procedure

  1. Battery switches OFF
  2. Connect battery negative first
  3. Connect battery positive
  4. Switch battery switches ON

Notes

  • A small inrush current or spark may occur
  • This is normal if no pre-charge device is installed
  • On large systems (multiple Quattros), a pre-charge solution is recommended but not mandatory if the installation has been designed accordingly

IMPORTANT – Orion XS DC-DC converters

Orion XS DC-DC converters must not be left with battery positive applied without a proper negative reference.

For this reason:

  • Negative must always be connected first
  • Positive must never be applied alone
  • Battery switches must be used correctly

This requirement applies regardless of BMS type.

SUMMARY – QUICK CHECKLIST

Disconnecting (winterizing)

  • Battery switches OFF
  • Positive off
  • Negative off
  • Batteries stored at 40–60 % SOC

Reconnecting (de-winterizing)

  • Battery switches OFF
  • Negative first
  • Positive second
  • Battery switches ON last

Key rules

  • No resistor required with Lynx BMS
  • Extra care with VE.Bus BMS
  • Orion XS → never positive without negative