By Boat Battery editorial team · 2 minute read · Editorial policy
What the BMS is, whether the enclosure is restrained and ventilated, how the bank charges from shore and engine, and who certified the work. Have the answers written down before you are asked.
Disclose the planned lithium conversion
Australian underwriters have moved quickly on lithium in the last two years, and the questionnaire is now standard on most policies covering vessels over a certain value. The questions are consistent enough that we publish them as a checklist you can work through before renewal.
Installation evidence for the insurer
The single most common cause of friction is not the batteries. It is an owner who cannot say who did the work. An undocumented install, however competent, gives an assessor an opening after a claim. A folder with the certificate, the BMS datasheet, a wiring diagram and photographs of the compartment closes it.
Marina conditions and unattended charging
Marinas are a separate conversation. Some now ask about lithium at berth application, particularly around charging while unattended. Berth-holder rules vary by state and by operator, and a few require a specific isolation arrangement for unattended charging.
Records when buying a used boat
If you are buying a boat with an existing lithium install, ask for this documentation before settlement. Retrospectively certifying someone else's wiring is expensive.
The folder to have ready
- Any certificate or assessment required by the vessel, insurer and jurisdiction
- BMS make, model and datasheet, including low-temperature behaviour
- Wiring diagram showing fusing, isolation and the shunt
- Photographs of the compartment, restraint and ventilation
- Charger specifications showing lithium profiles
- Cranking battery arrangement, showing separation from the house bank
Related installation planning resources
Use these notes to prepare your own measurements and questions. Check the exact equipment manuals and have the proposed system assessed for your vessel before buying or changing electrical components.
Calculate your boat battery capacity
The house bank calculator takes your loads, your nights on the hook, your solar and your alternator, and returns the bank, the DC-DC charger, the AGM equivalent and the weight you take off the boat.
Open the calculator