Mike’s Ten Commandments of Energy Management
06 March 2012
I can hear you readers loudly sighing, “Oh no, not another long winded post about batteries, amp hours, energy deficiencies and other drivel” I can also hear you lamenting, “And after all of the mistakes he’s made, now he considers himself an expert….”
Well, after three years of battling with keeping up on our daily electricity needs on the boat with a minimum of running the engine, I think we’ve finally found our solution. And, it was, of course relatively expensive. But I surely did learn a lot. So I thought I’d replay some of my learnings by proposing my Ten Commandments of Energy Management.
1. Get Intimate with Your Boat
Before you devise an energy solution for your boat, you should get a real good feel for what your energy needs are and under what circumstances you’ll be cruising. The first thing I would do if I was starting over again would be to install a smart battery monitor. I finally did this year and what an education this has been. It will tell you what each of your appliances, electronics and other devices consume, and the effect this is having on your battery bank. Not only is it informative but is also serves as a certain discipline. No longer is the extra light left on anonymous, it shows its footprint on the monitor in terms of amps. A cruising friend of mine confessed that after he installed his monitor, he would get up in the middle of the night to sneak a look at what he’s been using and what energy he has left. I have to admit that I’m prone to doing the same thing and it really provides an informed map of your boat’s energy habits. I now have a list of every light, instrument, appliance, etc. and the amperage it consumes. Factor into your considerations, how often you will be in a marina and plugged into shore power, underway under motor etc. It’s those long periods at anchor in lovely little bays and harbours which incessantly work away at your battery capacity.
2. Solar is Supreme
Solar panels, not long ago were very expensive and relatively inefficient. My first two panels which I purchased the year before we began cruising were about $8.00 per watt (my panel were 80 watts each and cost about $600.00 per panel) - this was just five years ago. Now in certain places (there’s a great place in Miami) you can purchase comparable panels for just over $1.00 per watt! Yes they occupy a lot of real estate on the deck/dodger/bimini or davit, but once they’re installed it’s almost as if they just smile amps at you. There is no maintenance, no sound, no moving parts and if you’re like most cruisers who are opting for warm, temperate (read sunny) climates, they’re just the ticket. My advice is to buy as much wattage as you can feasibly install and you’ll soak up those amps every day. I’m now in a position with mine that on nice sunny days, the solar panels replace my daily energy needs and you don’t even notice they’re there. Good old Sol, smiling benignly down on my boat supplies me with frozen food, cold beers, lights, entertainment and all of the daily electrical needs we have.
3. Wind is Wimpy
Many cruising boats, in particular sailboats have wind generators; I have one. In my opinion, they are expensive, noisy, somewhat unreliable, and parsimonious in their production of electrical energy unless you are in a gale. I have what is considered by many to be an efficient and relatively quiet model. Unless we are seeing 15 knots, the output is meagre. And when it does blow strong enough to make reasonable amps, it can sound like the Rolls-Royce engines of an Airbus A380 spooling up at the end of a runway in preparation for take off. Well not quite that bad but we sleep in our aft cabin and the wind generator is affixed to our davit arrangement and it certainly transmits a rumble into our cabin when it gets going. And usually if it doesn’t bug you on our own boat, it probably irks you neighbour’s boat. And they’re costly. Mine cost about $1500 not installed (I did the installation myself).
And then there’s reliability. Persistent readers of my blog will remember my travails last winter in the Bahamas when mine died and it took me more than a month to get the new circuit board. This may have been no fault of the manufacturer or supplier but I’ve heard lots of stories of failed wind generators
My advice: use the $1500 to buy 400 watts of solar panels ( shouldn’t cost more than $500) and use the other $1000 to go towards the arch or whatever other device you use to mount the panels.
4. Do Not Covet thy Neighbour’s Boat
Every boater’s solution, to them, is the ideal one. It’s just like which anchor works best.
Every cruiser has their favorite and with the stories of how well it performed in gales while other boats with lesser anchors dragged aimlessly through the anchorage. So don’t be taken in by your dockmate’s cruising boat with their “ideal” solution. Your consumption and lifestlyle factors may well be very different than theirs. Figure out your own solution.
5. Love Those LED’s
It was that fluorescent lights were the way to go when LED (light emitting diodes) were in their infancy. They (fluorescents) were “cool” and energy efficient when compared to incandescent and halogen lights. LED’s were the stuff of wrist watch backlights emitting a feeble greenish hue, good enough to figure the time in the middle of the night but not much good for lighting your vessel. Well, as they say, “You’ve come long way Baby”. The new generation of LED’s are powerful, inexpensive and best of all miserly in terms of energy consumption. If I count all of my reading lights, accent lights, navigation lights and house lights, I figure more than 26 lights on Sea Sharp. While it would be highly unlikely to have even half of these on at any point in time, they can be a big energy user. So curbing their consumption if important.
I’ve converted several to LED’s this year and I am happy to report that generally their consumption is one tenth that of their incandescent predecessor!! And the light is at least as strong. I was paying about $10.00 per light.
So work away at replacing your old bulbs with these amp-sipping little brighties!
6 Shave with Occam’s Razor
What has whiskers got to do with boating you wonder? Well, actually Occam’s Razor has nothing to do with shaving but is actually a line of reasoning that purports that the simplest answer, the one with the least variables or assumptions, is generally the correct one (AKA KISS - Keep it Simple Stupid). So, don’t get carried away with ultra high tech solutions with battery combiners, isolators, switches, monitors and the like. These things are vulnerable, particularly in a harsh salt water environment and the more stuff you have the more vulnerable you will be.
7. Bigger Ain’t Necessarily Better
Don’t you admire those cruising boats with their vast panoply of panels, veritable wind farms of wind generators, batteries filling their bilges and engine alternators with serpentine belts, intelligent monitors with their Medusa-like wiring harnesses….. Well, you probably should not provide for more energy needs than you’re likely to encounter in the normal mode of your cruising. This stuff is all fragile and sometimes you simply don’t need that much energy. So go easy….. Figure your requirements and design a system to meet those needs.
8. It’s the Small Things That Count
When I first started semi-full time cruising four years back, I would let things run unnecessarily figuring that a little bit here or a little bit there really doesn’t matter. One habit I had was leaving on my invertor and leaving the laptop charging all the time. My reasoning was that the invertor took little power (converting 12 volt DC to 110 volt AC) and that the laptop really couldn’t consume much power. After all, it just had a battery only slightly larger than those cells use to power ordinary household flashlights. Well, little did I know that I was consuming about 5 amps and hour; way more energy than it took to power my fridge, the largest single energy consumer on board! And Judy’s habit of turning on one light after another until the boat looked like the Cruise Ship Carnival Fantasy. Each of these lights consumed about an amp and I’ve counted six or seven on at a time.
So, while you shouldn’t get obsessive about it, keep tabs on the small amounts of fringe energy which can be managed.
9. Cheaper Ain’t Necessarily Better
When I was outfitting Sea Sharp with batteries after my first year cruising, I figured I’d buy Sam’s Club energizer batteries which claimed 85 amp hours, cost about $75 per and came with a five year warranty. I figured I’d use them hard and when they died I’d just go buy some more. Well, this was a false economy. They simply would not perform under the harsh charge/discharge cycles demanded on a cruising boat. I’ve since bitten the bullet and purchased AGM batteries which are much more robust, can handle repeated charging and discharging, don’t lose capacity as readily in a storage state and will charge much more quickly. Yeah, they’re much more expensive to purchase but they do the job. The others simply would/could not.
10. Don’t Follow this Advice
Strange finale you’re thinking considering the breadth and depth of advice I’ve just penned? Well, the point is that this is not an exact science and you’ve got to figure out your needs, your budget, your boat and your own solution. These above-noted observations and admonishments are based on my circumstances and trial and error. I did rely on many persons’ advice; some more heavily than others. In particular, Norman and Mike gave me sound advice but I also conferred with the general peanut gallery on www.sailboatowners.com and I got lots of good and not so good advice.
So my last piece of advice is to discount my advice and figure it out yourself!