Taking Out The Guesswork: Power Auditing For Your Yacht
When preparing for a new adventure or planning essential winter upgrades, it’s easy to fall into the habit of “best guessing” your onboard power needs based on past experience. But a more reliable approach exists - one that removes uncertainties and helps you get your yacht’s power system exactly right.
A well-executed power audit reveals exactly how much energy your yacht will need over a 24-hour period. With this knowledge, you can size your battery bank and charging systems correctly. Power audits also help you estimate what you can expect from your renewables - and how much extra charging you’ll need from other sources to ‘top up’.
How to Complete a Yacht Power Audit
A straightforward audit involves listing all electrical items (“consumers”) on your boat, detailing their power draw, and estimating how long each will be used during a standard 24 hour day. This information usually appears in the user manual or on the back of the device, often expressed in Watts or Amps. For clarity and consistency, convert all figures to Watts.
Power calculation tip:
Watts = Amps × Volts
Example: A 12V light at 1Amp is 12 Watts.
Steps for Your Audit
Identify every appliance or device that uses power.
Calculate what each DC device uses when running: Watts / Volts = Amps.
Multiply that by how many hours you expect it to run each day - this gives you Amp-hours for each device.
Finally, add up all the Amp-hours for every device.
By working through these steps, you’ll arrive at an accurate snapshot of daily energy demand.
To streamline the process, download our ready-made power audit tool - pre-filled with example figures you can edit to fit your yacht. This tool automates the calculations, helping you determine:
The size of the battery bank needed
The size and type of charging system required