Marine Lithium System Documentation and Handover
What drawings, settings, test results, manuals and emergency instructions should be handed over with a marine lithium battery installation.
A good marine lithium handover lets another competent person understand the system without reverse-engineering the boat. It also gives the owner a reliable reference when an alarm appears offshore, a charger is replaced, the vessel is surveyed or the boat is sold.
The paperwork should describe the installation that exists on board. A generic manufacturer brochure, an early quotation or a hand-drawn sketch that omits later changes is not an as-built record.
The one-line diagram
The core document is a legible diagram showing every major source, battery, protective device, isolator, busbar and load path. It should include cable size, protection rating and component identifier at the points where those details affect troubleshooting or safe modification.
Show the engine-start system and any emergency-parallel arrangement separately from the house bank. Identify circuits that remain energised when the main house isolator is open. If communication or control wiring can stop charging or disconnect loads, show that relationship as well as the heavy DC cable.
Equipment and settings schedule
Record manufacturer, exact model, serial number where useful, firmware version and installation location for the battery, BMS, chargers, inverter, shunt, monitor, protection and communications equipment.
For configurable devices, retain the settings rather than writing “lithium mode”. That label can represent different voltage, timing and temperature behaviour on different equipment. Capture charge voltages, absorption duration, current limits, low- and high-temperature limits, inverter cut-off settings, generator start conditions, alarms and state-of-charge synchronisation values.
Protection schedule
List fuse and breaker type, rating, interrupting capability where specified by the design, protected circuit and physical location. The owner should be able to find the correct device without opening unrelated lockers during a fault.
Include spare-fuse requirements and replacement restrictions. A physically compatible fuse with a different rating or interrupting capability is not necessarily an acceptable substitute.
Commissioning and measurement results
Attach the completed commissioning checklist. Keep measured values with the conditions under which they were recorded: battery state of charge, system voltage, load current, charging source, engine speed and equipment temperature.
A single statement that the system “tested OK” cannot be compared with future measurements. A table showing voltage at the battery and load, sustained alternator current and temperature, inverter current, solar output and alarm behaviour can.
Owner operating guide
The handover should explain normal start-up and shutdown, long-term storage, shore-power connection, expected state-of-charge range, alarm meanings, routine inspection and who to contact. Put urgent actions on one page that can be found quickly.
Write down what to do after a BMS shutdown and which services remain available. If recovery must wait until a fault is identified, say so; repeated resets can erase evidence or re-energise damaged equipment.
Source documents and change control
Retain current manufacturer installation and operating instructions, warranty conditions and any compliance or survey records that apply. Link to online copies, but also keep an offline copy because connectivity may not be available when the information is needed.
Every later alteration should update the diagram and settings schedule. Date the change, identify who performed it and keep the superseded drawing marked as obsolete. This is particularly important when a boat changes owner, because a neat installation can conceal undocumented bypasses or control changes.
What to request before final payment
Agree on the documentation deliverables in the quotation. Before accepting the work, check that model numbers match the equipment aboard, every drawing is readable, settings can be restored, photographs show concealed work and unresolved items are clearly listed.
Use the questions for a marine lithium installer before work begins and the used-yacht lithium inspection guide when evaluating an existing system.