Do not buy equipment, alter wiring or approve an installation solely because this website produced a number or recommendation.
Calculators are estimates
Calculator outputs depend entirely on the loads, duty cycles, temperatures, cable losses, charging conditions and usage patterns entered or assumed. Those inputs can be incomplete or wrong. Equipment also behaves differently in real installations. Measure your vessel where possible and keep an appropriate safety margin.
Content can be incomplete or out of date
Standards, manufacturer specifications, warranty terms, prices and regulatory expectations change. We may misunderstand a source, make a transcription error or fail to update a page promptly. Review dates indicate when a page was checked; they do not guarantee accuracy.
Use qualified professional advice
Marine electrical systems can cause fire, explosion, toxic gas exposure, electric shock, equipment damage or loss of essential systems. A suitably qualified marine electrician or surveyor must assess the actual vessel, installation environment and applicable requirements before work proceeds.
Product and comparison limitations
A product mentioned here may be unsuitable for your boat even if it appears in a shortlist. Manufacturer claims and prototype data are not independent test results. Pages clearly marked unverified must not be treated as purchasing recommendations. Check current documentation and warranty terms directly with the manufacturer or authorised supplier.
Emergency and safety information
This site is not an emergency service. If a battery is hot, swollen, damaged, smoking, venting or on fire, move away, warn others and call Triple Zero (000) when it is safe to do so. Follow directions from emergency services and the battery manufacturer.
Check the primary sources
Start with our authority resources, read the calculation methodology, and use the contact page to report a possible error.