Sunday, June 23, 2013

Watts, Amps, and a big fat headache

One of the things on The List (you know the one that Tim threw away and I rescued from the trash...) was to do our electrical consumption spreadsheet so we could plan what we were going to need in the way of solar panels and wind generator. I had originally been scheduled to do 2 canvas jobs this weekend but they both bailed for various reasons so I was left with a rainy weekend and nothing to do. There was no more opportunity for excuses so I dug out my spreadsheet, reading glasses, scrap paper and pen and set to work.

I started at the bow in the V-berth and worked my way to the stern, checking each DC item in the boat and marking it in the spreadsheet - watts, amps, average daily use, part numbers and where we bought them, and running total. I had previously done some research on boats about the size of ours whose owners had blogged about their total usage and they seem to run between 190 amps per day and 250 amps. (Comments please if yours is very different and why.) As I worked, I estimated high on everything since I have only our current use as weekend liveaboards and absolutely NO idea what our actual use is going to be while cruising. I came in at 205 amps but there are several things we are going to change to curb that, including 2 cabin fans that are hogs at 10 watts each and run for a good part of each day. One thing I noticed while doing some research on things that were already installed in the boat and that we had not bought since, was that even two years makes a HUGE difference in the efficiency of models of things. Take for instance our bilge pump. While I don' t have my spreadsheet right in front of me  to give you exact figures (working on the marina computer), our pump uses more than twice the amperage that the current model of it uses. While I realize we can't replace everything electrical in the boat, there are certain things that stick out on my spreadsheet that can be replaced relatively inexpensively. Since electricity is a currency on the boat, sometimes it pays to spend a little more for the product in order to save on your usage.  We have already replaced all our lightbulbs with LEDs, and the spreadsheet includes our new refrigerator which we have yet to install, so we're already moving in the direction of self-sufficiency.

I did learn a ton this weekend about electricity, a subject that has not been a good one for me prior to this, and I feel pretty confident that we can meet our power needs with a little creative thinking. After Tim reviews my spreadsheet I'll post it for you all to peruse. By the way, he is going to rest a little now because I've been driving him crazy with all the questions :)


Bill K said...

Now this got me laughing.

" By the way, he is going to rest a little now because I've been driving him crazy with all the questions :)"

BTW Do not buy that new bilge pump that keeps checking for water as it uses more electricity and is annoying.

Bill Kelleher

Robert Salnick said...

Tim -

If you are worrying about the power consumption of your bilge pump, I submit you are worrying about the wrong thing. Your bilge pump should be consuming approximately zero power. If not, then you should be looking for the leak...

s/v Eolian

Deb said...

@Bill - he deserves the punishment don't you think since he made me take over the list???

@Bob - Our bilge is definitely not a dry one. Our refrigerator dumps into as does our A/C (which will be removed soon) and the various leaks we still haven't gotten around to fixing. Yes, we should be looking for them but at the moment we have kind of a full plate. We'll have plenty of time to look for leaks while we're on the hook on the coast.

Ante Mazalin | SailingEurope Group said...

You are definitely right about electricity > currency on the boat.
Two Summers ago, I was faced with the task of powering my 48V motor without the luxury of readily available AC charger outlet.

Web searches lead me to many 12V solar charger solutions, and a few 24V solutions, but I was unable to find any solid direction to charge my 48V Briggs and Stratton system