Electrical loads

I’ve spent a fair amount of time in the last few days researching electrical stuff in preparation for a “grand rewiring” of the core components: the breaker panels, electrical gauges, switches, and charging systems.  I am starting to get a pretty good understanding of how everything should fit together, and some of the components I want.

I decided it’d really make sense for me to make some progress on the whole “map the electrical system” thing I talked about a month or two ago but never made progress on.  So tonight I went from stern to bow, keel to masthead, and made a rather large spreadsheet of all the electrical loads I know about on board and some details about each: the general area in the boat where the load is; any idle current drawn if the device has “modes” (e.g., the autopilot draws some current to monitor the heading and display some information, but a whole lot more current when it’s actuating the rudder to correct the heading); current drawn while the device is “active”; the breaker switch the load’s on right now; and a guess at “active” hours for each load while underway.  There are a lot of gaps in my data but at least I now have a mostly comprehensive list of the electrical loads on board.

I counted 72 distinct loads for now.  That’s being pretty granular and counting things like individual speakers.

The biggest daily amp-hour gobbler will probably be the fridge, which I’d expect to eat up around 50 AH daily (about a quarter of my okay-to-use house battery capacity).  That’s probably more than my solar panels will replenish all by itself, not to mention other loads like running lights (none of which are LED right now) which are only slightly less power-hungry than the fridge from a daily AH perspective.

Eventually I’d like to do some measuring of stuff like the fridge a little more precisely than just taking a one-time sample from my ammeter — maybe it won’t be as bad as I’m calculating.

I also have a few new loads I’m considering adding sooner or later: on-board DC air conditioning (feeling more and more worth it); a few more LED lamps (luckily, very cheap in terms of load, if not in terms of cash); some gauges for the fuel and water tanks, which currently have none; and maybe looking farther out, a RADAR, chartplotter, and SSB radio.  I think it’ll pay in the end to sort of plan for these things now so I have space for them in my new panels, at least.

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