Josh, if you do a search (here or Google or almost any other boating forum) you will find that to make one you need to have the amperage draws to be able to do so.

Here's one example: [url]http://c34.org/bbs/index.php/topic,3976.0.html[/url]

West Marine online Advisors have one, too.

Josh, I'm sure you're aware a voltmeter wouldn't give you the amperage. Did my link not give you the info you need?

If you have a battery monitor you could turn off the charger and everything else then one by one turn on your equipment. You should get a decent idea off the draw of each item, on the monitor. An advantage of this method is that it is measuring not just the equipment but the draw of the associated intstalation, taking into account such things as wire length etc. You would have to put a motor such as a winch under load to get a decent idea of what it is drawing. Even if it is not perfectly accurate it will usually be consistant which can help warn of things which are not working. On one aircraft I flew a lot I could tell if a single bulb was burned out and usually knew which one it was by the difference in the amperage draw.

Josh,

This is a snippet from my spreadsheet. The numbers represent amps of current draw.

Refrigerator 5.50
Fan - Lo 0.20
Fan - HI 0.30

Nav Instruments 0.20
VHF 0.40
Water Pressure Pump 5.00
Macerator Pump 8.00
Anchor Washdown Pump 5.00

Cabin Lights (LED) - each 0.10
Head Light (F) 0.80
Galley Light - Aft (F) 0.90

Anchor Light (L) 0.10
Running Lights (all) 1.70
Steaming Light 0.70
Deck Light 1.80

F- fluorescent
L- LED

From a Google search on "boat energy use":

[url]http://commutercruiser.com/how-to-ca...aboard-a-boat/[/url]

I'm sure a few Google searches would turn up other lists.

I read that article Stu, interesting. But I wonder about one thing when he was talking about his coffee maker that uses 1425 watts he was thinking 10 amps on 110volt. But if you powered that thing through an inverter, would that inverter not actually end up drawing about 100 amps from the 12V batteries to make that power? Or am I misunderstanding this? We don't use inverters, other than a little 75 watt one to power our TV, that unit draws 5 amps from the batteries which is what I would expect as the TV draws 60 watts. So what's the amp draw on the batteries with big inverters and 1500 watt loads?

Bud, your math is right, usually about 10X the DC draw for AC off an inverter. I folks have adequate house bank capacity, then they should feel free to use electric coffee makers which most likely take 5 to 10 minutes to "perk" and then have resistance heaters on the bottom. "More power to them," I say ;) Without getting into a discussion about the best way to "make coffee on your boat," I use our stove, a Melita filter and a thermos. :cool:

[QUOTE=stu jackson c34;16655]Bud, your math is right, usually about 10X the DC draw for AC off an inverter. I folks have adequate house bank capacity, then they should feel free to use electric coffee makers which most likely take 5 to 10 minutes to "perk" and then have resistance heaters on the bottom. "More power to them," I say ;) Without getting into a discussion about the best way to "make coffee on your boat," I use our stove, a Melita filter and a thermos. :cool:[/QUOTE]

1425W AC / 12V X 1.15 = 137A

This is the DC draw at an 85% inverter efficiency... Use 1.1 for 90% or 1.2 for 80% 0r 1.35 for items like computers of TV's that go DC to AC then back to DC... Oh and at 137A you'll be lucky to maintain 12V at the batteries so you might want to figure on 11V or so instead which will bump the DC draw closer to 150A...

The simple safe "guideline" is; 50A for 500W or 100A for 1000W, 150A for 1500W & 200A for 2000W......

For AC the watts to current calculation looks like this;

1425W / 120V = 11.9A

For DC the watts to current calculation look like this;

1425W / 12V = 119A

Multiply the DC amps by 1.1 (90%), 1.15 (85%) or 1.2 (80%) based on your inverters efficiency to get the total DC load the inverter is applying to the batteries....

[quote=stu jackson c34;16655]Bud, your math is right, usually about 10X the DC draw for AC off an inverter. I folks have adequate house bank capacity, then they should feel free to use electric coffee makers which most likely take 5 to 10 minutes to "perk" and then have resistance heaters on the bottom. "More power to them," I say ;) Without getting into a discussion about the best way to "make coffee on your boat," I use our stove, a Melita filter and a thermos. :cool:[/quote]

We use the stove and a french press on the boat, makes a nice fresh cuppa joe. But we got one of the Keurigs at Xmas, and a couple of the eco baskets so we can use our own coffee and feel good that we're not filling the local landfill with K cups as well as save a buck (or ten). Man, it is pretty nice to have a nice fresh cup every time. The old drip pot is history. So when I saw the Keurig in the article, I got thinking boat, but I was pretty sure it was massive amps. French press works real good and real economical, in line with our stingy power consumption policy.