This section lets you enter the estimated daily power consumption of your onboard devices in amp-hours (Ah). Amp-hours represent the amount of current drawn over time. For example, if a device uses 2 amps for 5 hours, it consumes 10 Ah.

• Use typical daily usage values for each item.
• You can add custom items if your equipment is not listed.
• Accurate inputs here help size your battery bank correctly.
• Consult the manuals supplied with your equipment, or look them up online, for typical values.
• Better - Use actual current measurements taken on your own installed systems.

Configure your system parameters here:

• Battery Voltage: Select your system voltage (usually 12V or 24V). This affects energy calculations.
• System Efficiency: A fixed 90% efficiency is assumed to cover inverter, wiring, and battery losses. Advanced Mode will allow detailed efficiency settings.
• Autonomy (days): Number of days you want your battery bank to supply power without recharging. More autonomy results in a bigger battery and recharging may become a problem, but results in fewer cycles thus providing longer battery lifetime.
• Usage Profile: Select the profile that best matches your boating lifestyle to estimate battery cycle usage.

Enter the cost per 100 Ah for each battery chemistry type. This calculator estimates total 10-year costs, including replacements, based on typical cycle life and depth of discharge.

• Flooded lead-acid batteries are usually cheapest but require maintenance.
• AGM and Lead Carbon offer better performance and lifespan.
• Lithium batteries have higher upfront cost but longer life and lighter weight.
• Research your local supply market for battery prices; what is important is the relative cost of each battery chemistry rather than the absolute accuracy of the price.

Input the estimated daily amp-hours supplied by your charging sources:

• Engine Alternator - Not easy to estimate, if you have a battery monitor record a few cycles so that you can make a more informed guess.
• Solar Panels - Lots of dependencies: Season, Latitude, Temperature, climate, mounting angle of the panel.
• Wind Generator - Unlike solar panels these can work 24/7 if you are cruising in the trade winds.
• Water Turbine - Does nothing if your boat is not moving. Experience and manufacturers advice can help.
• Diesel Generator - Practical on a larger boat and can be sized to exactly match the load, giving good efficiency.

This helps assess if your charging capacity meets or exceeds your daily consumption.

The calculator also suggests solar panel wattage based on your solar input and system voltage.

This summary shows:

• Your selected usage profile and estimated battery cycles per year.
• Daily and adjusted loads considering autonomy and efficiency.
• Required battery capacity per chemistry, replacement intervals, and total 10-year cost estimates.

Use this to compare battery options and plan your system accordingly.

The chart visualises cumulative battery replacement costs over 10 years for each chemistry type.

• Helps you understand long-term investment and replacement schedules.
• Hover over lines for detailed yearly costs.