estimating power consumption?

[l0keman]

I was wondering if there was a way to figure out how much battery power would be drained over a course of time to get the right amount of battery power. My boat has no electrical system in it atm. I figure I want enough power to handle the most demanding situation and then a little more to be safe... err comfortable really.

Is there some formula or something that will figure the combined power drain of so many appliances over a course of time so i can figure out how many of what size batteries to buy?

[Looking]

If you are just beginning to design your electrical, I would highly recommend Nigel Calder's "Boatowner's Mechanical and Electrical Manual"

[camaraderie]

Here's a bit of a list to help. What stuff do you have that is not on this list that we can help with?

Group	Device	Amps
Communications	CB Receiver	1.00
Communications	SSB Receiver	1.50
Communications	SSB Transmit	25.00
Communications	VHF Receive	1.50
Communications	VHF Transmit	5.00
Entertainment	Tape receiver	1.00
Refrigeration	Refrigeration(typical)	5.00
General Lighting	Cabin Light (40W)	3.50
General Lighting	Fluorescent Light (26W)	1.80
General Lighting	Fluorescent Light (8W)	.70
General Lighting	Hand Held Spotlight	10.00
General Lighting	Spreader Light	8.00
Heat	Forced Air (11,000 BTU)	3.00
Heat	Forced Air (28,000 BTU)	10.00
Instrument	Knotmeter	0.10
Instrument	Wind Speed Indicator	0.10
Misc..	Anchor Windlass	80.00
Misc..	Auto Pilot	4.00
Misc..	Bilge Pump	2.50
Misc..	Cabin Fan	1.00
Misc..	Fuel Pump	3.00
Misc..	Horn	3.00
Misc..	Inverter (Sm. Microwave)	100.00
Misc...	Inverter(Nicad Charger)	1.50
Misc...	Propane Valve	1.00
Navigation	Depth Sounder	0.10
Navigation	Loran	1.00
Navigation	Radar	4.00
Navigation	Recording Depth Sounder	0.50
Navigation	Satnav(average)	0.20
Navigation	Weather Fax	2.40
Navigation Light	Anchor Light	1.00
Navigation Light	Masthead/Steaming Light	1.00
Navigation Light	Running Lights	3.00
Navigation Light	Strobe Light	0.70
Navigation Light	Tri-Color Light	2.00
Pump	Bilge Pump	5.00
Pump	Fresh Water Pump	5.00
Pump	Head Pump	18.00
Pump	Wash Down Pump	10.00

[sailingdog]

Now create a budget, since Cam has kindly posted a list of equipment and their approximate use rates.. and figure out how many hours you use each piece of equipment on a given day... and then multiply the hours by the amperage and get a total of AmpHours used per day.

Your battery bank should be 2-4 times this size as a rough estimate. It depends on what type of charging systems you have, what kind of sailing you do and your financial budget. If the battery bank is 4x the daily size, you can got two days without having to re-charge the batteries. You generally don't want to draw the batteries down below 50% charge, as that will drastically shorten their lifespan.

[poopdeckpappy]

So, assuming 8hrs

radio is 6.5 amps x 8=52
Refer is 5 amps x 8=40
Nav Lgts 5 amps x 3=15

Total 107 ah x 4 = a bat bank of 428 amp/hrs ???

[Pamlicotraveler]

Originally Posted by poopdeckpappy

So, assuming 8hrs

radio is 6.5 amps x 8=52
Refer is 5 amps x 8=40
Nav Lgts 5 amps x 3=15

Total 107 ah x 4 = a bat bank of 428 amp/hrs ???

Radio is 1.5 to receive..its only when you transmit that it would be 5 so you wouldn't use that much.

To get the 2 days I would assume the refrigerator over 24 hrs is 24 x 5 or 120 ah - So if you are trying to make it 2 days, That's 240 ah total, right Cam? And with that to have double AH bank that would be 480 bank for just the refrigerator. It would seem that's the one that get's you.

[Pamlicotraveler]

By the way Cam....that list is great.

I might go laminate it and sell copies of the "Laminated Power Consumption Guide" on eBay

[l0keman]

sweet! thanks for all the info... the boo that was referred just so happened to have a few pages posted for a test drive... lucky for me it was the section on figuring out draw like this.

as for the stuff not on the list... I'm thinking a tiny microwave, a 14 inch LCD and a playstation 3. Maybe a stereo with 4 speakers... 2 in cabin and 2 in the cockpit. I should just be able to get the amps off the label on them right? I'm just fixxing up a 1975 Chrysler C-22. I just want to be able to go to the marina and relax on the boat for a nite or two or take it out to the islands. You know when the kids are out of town and the wife is working. She is a day sleeper/nite worker. I could fill the cooler with tequizas and coronas and spend a day or two relaxing. Gonna hang out, with the wang out.

[poopdeckpappy]

ok, I'm getting there, Thanks

[Pamlicotraveler]

Originally Posted by l0keman

I could fill the cooler with tequizas and coronas and spend a day or two relaxing.

You know...we should start a new thread about this. Tequiza is my favorite sailing beer because you don't need the limes like you do for Corona. I didn't know anybody else had discovered it. I have a six pack of Tequiza just waiting for me on my boat!