24
Tech Talk with SeaBits
TESTING & DOCUMENTING YOUR BOAT’S POWER SYSTEM by Steve Mitchell I like to say your boat has two beating hearts — your method of propulsion (engines and/or sails), and the power system that makes it all possible. Understanding that power system is critical to safely operating a boat, enjoying your journey, and relaxing along the way. UNDERSTANDING YOUR SYSTEM Figuring out how your boat’s power system works should be high on your priority list. This should include basics, such as: the type and capacity of each of your battery banks, how each one is charged, what each bank is connected to, and any switches or devices that combine or separate the banks. Unfortunately, developing real understanding of these nuances requires a manual process that involves some trial and error, depending on whether certain components are hidden or hard to reach. I usually start with the basics — finding all of the batteries and banks and inspecting each of them. Take pictures of the battery labels and capacities so you can look at them later, note any date codes on batteries, and track down batteries for things like generators and thrusters, which can be harder to find (or even hidden!) compared to your house bank.
Unlabeled electrical chargers and switches can be frustrating and confusing As you investigate your system, spend the time to label everything you find, if it isn’t already. Clearly label individual wires or connections at both ends, as well as any switches or devices that can be manipulated. It’s especially helpful to add “state” labels near these sorts of devices so that in an emergency or panicked moment you know what switch is supposed to be in which position to do the thing you want it to do! 48º NORTH
DOCUMENTATION TOOLS Once you understand the basics of your power system, take a few hours to document it. This can be as simple as something drawn out on a piece of paper with the batteries, sizes, connections, and charging sources. Or you can get a bit more detailed and create what is called a single line diagram. This is like it sounds; a simplified diagram showing a single line for the key parts of electrical flow and all of the components involved. I find it helpful to add things like flow arrows, which are not usually found on traditional single line diagrams, showing which way the current flows for typical operations. This can help you understand what should be charging and the sources of that charge. You can also create multiple versions of these documents to show what is being used at different times — while charging at the dock, underway, and at anchor. Single line diagrams can be a bit complicated for those without an electrical background, as they can use specific electrical symbols to represent things like circuit breakers, fuses, and the like. Use whatever works for you to represent how things are connected. To create a single line diagram, you can use Visio for Windows, OmniGraffle for the Mac, or a host of other apps for tablets and smartphones. There are also web-based tools like SmartDraw which are even more powerful and easier to use in many cases. You don’t have to use electrical symbols unless those are familiar to you — after all, this documentation is primarily designed to you. Creating it this way allows you to update things easily and produce different versions of it depending on the scenario. Consider laminating a version of it and place it near battery switches or electrical components to remind you how it all fits together. TESTING YOUR SYSTEM The next step is to understand how your system performs in each major mode. This can be done at the dock, and I highly recommend doing this ahead of time, documenting baseline performance. I also recommend doing this every year at the start of the season. Not only does this remind you of how it works, but it puts the system through a good test before you’re out on the water somewhere needing service. Test your system in the usual ways you use your boat. I use the following: at the dock, underway, at anchor charging, at anchor during the day, at anchor during the night. You’ll need a way to record your test results such as a notebook or spreadsheet, a good idea of what you have on/off during these times, and a bit of time. I recommend recording as much information as possible so that if you need to go back later on, you don’t have to re-run the tests.
24
APRIL 2021