Keeping Cool

This is a technical post. Sorry. There’s no human interest angle, no insights, no soul searching. This post is all about keeping food fresh and managing power. Sorry.

Okay, if you’re still reading… as you may already know, I’ve spent far too much time creating an elaborate spreadsheet that calculates power needs, solar potential, etc. Now, as I kinda expected, the rubber is hitting the road. The real world is getting in the way of all my great extrapolations.

Before creating my solar calculator extravaganza of a spreadsheet, I installed a State of Charge monitor in the boat, so that I could monitor the comings and goings of power onboard our boat. Once installed, I isolated each power consuming device and monitored how much power it used. So, I thought I had this pretty well in hand. However, three variables have popped up since leaving my home dock that I hadn’t quite accounted for.

First, and most importantly, my fridge is not behaving at all like it did at the dock. At CYBC, my fridge, built in 1984, with it’s semi-broken thermostat, had a simple pattern of energy usage. It was on exactly 50% of the time, consuming about six, 12v amps. In the year that I watched it, it never seemed to vary from this pattern. However, in the past few weeks, that pattern has changed. On hot days, it’s now on 75% of the time – or more! And while it used to ensure that I offered the coldest beer on the dock, it now seems to be struggling to keep ice frozen.

I’m not sure whether the change in its habits is because we are further south, in hotter weather, but I doubt that’s it. Yes, we’ve had some killer weeks of hot weather as we’ve travelled, but they are not much different from August in Toronto. Another possibility is that the water is warmer, which means the whole boat is warmer. When the engine finally shuts off, it does seem like it takes longer for the cockpit floor to cool down, but this also seems an unlikely reason to me. Another possibility is that the fridge doesn’t like lower voltages. Our new batteries are great but they are no pushovers. You can pump all kinds of power into them and they will absorb it without much change in the battery’s voltage. So it could be that our fridge just doesn’t like operating at 12.2 to 12.8, where our batteries spend most of their time.

Whatever the reason, finding out that the one item that uses more power than all other items put together is actually drawing 50% or more power than you anticipated is really gumming up the works. Adding insult to injury, we are also finding that our solar array is not putting out as much power as we forecast. There are two reasons for this. The first is that the new solar charge controller seems to glitch every so often, leaving the panels switched off until you notice and unplug and re-plug the panels into the controller. (Is Microsoft behind our solar controller???) The second reason is really one I kinda anticipated, but may have underestimated: The days are getting shorter! That’s cutting into our solar time, big time.

So, we’ve been considering some mix-and-match options, and here’s what we’ve come up with:

Option 1: Replace the fridge, or at least the thermostat. Newer thermostats are smarter and may save us some power. A new compressor would definitely reduce power consumption to maybe half of what we currently consume. Ideally, we’d add insulation around our box, but in our case, that would require a significant carpentry project.

Option 2: Buy a portable fridge. Many boaters are raving about these portable, Engel fridges. They are about the size of a large cooler on the outside, but quite a bit smaller on the inside. They consume very little power. We could put one in our quarterberth or maybe under the table in our salon. We could continue to use our fridge for beverages and run it less often or use it like an ice box.

Option 3: Change how we use the fridge. Find a way to keep perishables in a kind of icebox within the fridge. Run the fridge during the day only and make do.

Option 4: Add more solar. We have two new panels and two older, cheaper ones . We could ditch the crappy panels and replace them with better panels. I expect we could increase our power potential by about 50% by doing so. We suspect that getting rid of the older panels will also stop the controller from glitching.

Option 5: Eat only crab, and catch fresh ones everyday. This seems entirely possible, but it may make leaving the Chesapeake difficult.

For now, we are going to try option 3, but we’ll give option 5 a try as well.

4 comments

    • Jigg’s dinner was a regular occurrence when I was a kid. Salt beef, hardtack, potatoes, turnips and cabbage all boiled together until you could eat it with a straw!

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  1. Hi Thom. Thanks for the blogs… I read them all.

    Ref Fridge power issue – check your fridge thermostat manual. Many fridges have 2 internal modes – (1) cool fast and use more power (for people the weekenders); (2) cool slow and save power – for live aboard. On my unit, I can change the setting with a resistance.

    Ref alternative power – speaking with many people that went south and/or live aboard, I was told that solar is great in the northern hemisphere (longer day) and wind generator are best south (constant breeze). Just sharing.

    Hope this help

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  2. Hi Kids,

    Jill and I really enjoy your posts.

    Thanks for the spreadsheet. I’m looking forward to opening it on my laptop. I looked at it on my gadget using the magnifying glass on my Swiss Army knife.

    Keep an eye on that next storm forming near Florida.

    Like

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