By Boat Battery editorial team · 2 minute read · Editorial policy
Compare the complete installed system: battery, protection, charging, monitoring, labour and handover. Two quotes for the same amp-hours can describe very different jobs.
Quote brief and load requirements
Start with a one-page brief. Record your present bank voltage, the appliances you actually use, nights away from shore power and the charging equipment already aboard. Add photographs of labels, the battery compartment and the route between the engine and house bank. A quote based on that information is more useful than a price requested for ‘200 amp-hours of lithium’.
Retained equipment and inspection allowances
Ask each installer to separate retained equipment from new equipment. An existing shore charger may have a suitable profile, but its settings and behaviour still need checking. Cable that looks substantial is not evidence of adequate current capacity or acceptable voltage drop. The quote should explain the proposed inspection and what happens if hidden defects are discovered.
Commissioning costs and exclusions
Put commissioning on its own line. You need the charger settings, protection schedule, labelled isolation points and a demonstration of normal operation and alarms. Clarify travel, marina access, disposal, taxes and exclusions before comparing totals. A lower initial price can become a higher final cost if these items are left open.
Warranty and aftercare responsibility
Compare responsibility as well as price. Identify who handles a battery warranty claim, who supports a charger configuration problem and who returns if the system trips on the first weekend. Keep the agreed scope with the invoice and equipment serial numbers. The best quote for your boat is the one whose assumptions you understand and whose work can be checked at handover.
Send the same brief to every installer
- Loads, bank voltage and target endurance
- Battery compartment photographs and dimensions
- Existing charger and alternator model numbers
- Itemised protection, commissioning and documentation
- Written exclusions and responsibility for follow-up
Frequently asked questions
Should I buy the battery before getting a quote?
Agree the system design first. An installer may identify limits in the charging system, compartment or intended loads that change the battery choice.
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