Learnings, Tips & Tricks: Electrical Power Consumption

By Rich


Step 1: Make sure your House batteries haven’t gone bad. I’m only partially kidding. Coming off of an adult life spent almost entirely racing instead of cruising aboard sailboats, we knew we’d have a lot to learn about topics such as power consumption when living aboard.  Watching the pace at which our batteries drained during last year’s three-day weekends caused us to go into a spasm of power conservation modifications over the winter. Happily, this season we learned that the problem wasn’t excessive consumption on our part, it was worn-out batteries. That meant that we took a series of steps to cut our consumption that basically have us ready for the zombie apocalypse now that we have new batteries. One side note: the consumption figures sited below are for Rich living and working full time alone on the boat. Obviously consumption may rise when we are actively cruising with guests, but in those scenarios we will be running the motor more regularly so preservation of the battery charge becomes much less of a concern in general.

Last season we didn’t spend much more than a day to a day-and-a-half aboard without motoring somewhere, so we really didn’t have a firm grasp of how much power we used and how long the batteries would go before needing a charge. Still I suspected that I would need to consume far less than I had been doing during my few Fridays working from the boat. During the winter I decided to set a goal of cutting consumption enough that I only needed to run the engine to re charge every two days. We replaced most interior lights with LED bulbs and I bought a Lenovo X1 Carbon laptop that runs off of a DC cigarette lighter type of outlet, replacing my large Dell brick of a laptop that required AC power off of the inverter. This change cut laptop power consumption by more than half, to only around 7/10ths of an amp on average during the workday. In addition, we bought a portable solar panel that we use exclusively to charge iPads and iPhones.


The latter have proven to consume an alarming amount of power and have proven to be very finicky about charging off of the DC cigarette lighter outlet. Oddly, they are quite happy to charge off of portable rechargeable (“lipstick”) type of batteries, however, which we replenish with the solar panel.

I addition I made a series of behavioral changes to cut consumption further. Whenever possible, I use the manual foot pumps for fresh water instead of running the pressurized water. I’ve rejected the electrical aft toilet almost entirely in favor of the manual forward head. The combined effect of all of these measures has reduced my 24-hour weekday consumption to only 10 amp-hours on average living and working full time aboard. As I type it is Friday and I last charged Sunday afternoon. My instrumentation shows only about 45 amp hours expended during that period, which means that our two 210 amp-hour house batteries provide more than enough battery capacity to meet a full work week’s needs and more. That eliminates the need to idle the motor purely to charge the batteries; I can simply wait until we use the boat on the weekends and re charge the batteries when we would ordinarily be running the engine anyway.

Ironically, making such strides in energy conservation created another dilemma. Eliminating the need to idle the engine to charge the batteries raised the issue of how I would keep food cool without running the refrigerator every couple of days while I charged the batteries. As a workaround I have decided to use 10-pound ice blocks ($2.50 each) to use the refrigerator as an icebox.


Two or three blocks per week seem to do the trick. Whenever I run the motor I will run the fridge, but at this point that will just be a bonus cooling between ice blocks. Whatever the ice costs this summer it can’t possible rival the fuel & maintenance costs of idling the diesel just for the fridge.

So happily, in the case of electrical consumption our lack of knowledge worked to our advantage: we’ve implemented a series of conservation measures that allow us to live aboard for a week or more without the need to recharge. Not bad!

2 thoughts on “Learnings, Tips & Tricks: Electrical Power Consumption

  1. This balance of batteries, ice, solar panels and engine are truly nice reading. Oh! And they’re also FAR beyond the thinking capacity of the ‘family captain’ of the ‘Endeavor(s)’

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