Family Magazine

Managing Power on a Cruising Boat

By Behan Gifford @sailingtotem
paddling home, racing the sunLiving off the grid, providing your own power, is a tremendous feeling. On Totem, it’s one of the compelling aspects of life afloat, hand in hand with a more simple life and a lighter carbon footprint. Relying on our solar panels and wind turbine to supply power needs instead of plugging in is liberating.
That good juice from the sun and the wind is stored in our house battery bank. Currently, that bank has 660 amps total from six 220aH 6v AGM batteries.  When we have steady trade winds, and sunny days, these meet our needs pretty well. For a long stretch, that’s been enough. We’re all power-watching hounds: even the kids understand the numbers on our electrical panel that show the voltage level in the house bank, and the net amperage being used or added at any given time.
Lately,  we’re falling short on power needs. Part of it is generation. Part of it is use. Part of it is storage.
-On the generation side: as it happens, the equatorial zone where we find ourselves often has a lot of clouds- part of this whole convergence zone thing that produces squalls that increase seasonally, as they are now. Not great for solar power generation. It turns out isn't known for having a lot of wind, either (you've heard of the doldrums?). There are windy squalls, yes, but they don’t last long; the steady trades aren't here. The moniker “land below the wind” is well earned. We do have wind and sun and make power from both, just not at the level we'd like- but that's relatively short term. Once we leave these low latitudes, we can more consistently generate green power.
-On the usage front: we’re simply using more energy now than we were back in 2008. Our biggest power hog is the refrigeration, which suffers mightily in the tropics: the 32 year old insulation is ineffective. Our needs are changing, too. As the kids get older, we’re losing more power to the #2 use after refrigeration: digital devices, primarily powering computers. That’s not going to change, so we have to.
-On the storage side: Totem’s house battery bank has been declining for a year. When marine batteries start to go, it's possible to have a slow demise, but things can happen very very quickly. For a while, it was worrisome- juggling a lot of different projects on the boat, we weren't sure when we’d be able to have the magic nexus of time and money to get a new set of batteries installed… but we had to. You don’t get a card to Pass Go wait once the batteries are dead.
The next few months are bringing a really exciting trifecta of power change to Totem. I never thought twice about our power use when we had a conventional land life, but I am positively tingly thinking about what’s coming up:
1.A Silentwind wind generator will soon significantly upgrade Totem's wind power capability.
2.We are adding a solar panel. I big hearkin’ panel. It will double our solar-powered amps.
3.New batteries to replace our house bank are on on the way, and will increase our capacity by 50%.
This is huge. It’s going to take some work, but nothing we (or any self-sufficient cruiser) can't handle, from building the box to hold the 600+ pounds of new batteries to installing the turbine and panels and wiring everything up.
What do you want to know about power on board? Who has solar, wind, or generators helping meet their needs? In the coming weeks, I’m going to get into detail on the work we’re doing and the changes that are happening to our own mini power grid, and want to make it as useful as possible.
Green energy fans like the Totem crew always like to read these posts on the Sailfeed website.

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