Energy Audit

[Squidd]

Looking to "power up" my boat, buy batteries and thinking solar charger but not sure how to do an energy audit when I'm not sure what my usage is going to be...?

Weekend crusier, sitting on trailer at marina during the week so not alot of "shore power" to charge off of unless I spend the night in a transient slip...(which I probably will do one night a weekend)

No TV no AC, probably no heater (unless is slip) only "major" usage is I will have a 12 v 75 watt coffee maker for a pot or two in the morning...

Other than that not much draw, beside anchor light one maybe two nights, 10 watt deck light occasionally and basic interior lights... and VHF while crusing and weather reports at night.

I have a pull start outboard so no starter battery needed, so was thinking one (maybe two ??) average size deepcycle batterys and a 10 watt solar panel to recharge during the week (might be two weeks between weekends)...

My impression is with that low a panel a regulator/controler was not neccessary, but I don't want to cook the batterys but I do want them charged up for the weekend excursion...

Am I in the ballpark or am I missing some common useage/appliances that I should add to audit...?

[-OvO-]

12 v 75 watt coffee maker for a pot or two in the morning...

French press - use fire instead.

[Squidd]

Originally Posted by -OvO-

French press - use fire instead.

I did almost 20 years doing the "Mother Earth News" Back to the land/Homesteading thing... heating AND cooking exclusivly on wood...

Now days a good coffee pot and a microwave are practicly neccessities...(but I can do without the microwave on the boat...)

[SlowButSteady]

Originally Posted by -OvO-

French press - use fire instead.

Or a stove-top espresso maker, like this:


And switch over to LEDs in as many fixtures as you can. Cabin lights, since they tend to be used for several hours each evening, can really suck up the electrons.

[Squidd]

How long does it take to boil water on an alcohol stove..?

[Lake Superior Sailor]

Who really cares as long as your on the boat! it's not like your in a hurry to go to work... About 5 minutes.. Dale

[SlowButSteady]

Originally Posted by Squidd

How long does it take to boil water on an alcohol stove..?

About the same amount of time, or maybe slightly longer, as with a propane stove.

Originally Posted by Lake Superior Sailor

Who really cares as long as your on the boat! it's not like your in a hurry to go to work...

Exactly!

[Squidd]

I'm never in a hurry to go to work....

Just that ever since the "split the kindling, start the fire, wait for the stove to warm up, add more wood, boil the water" 1/2 hr routine I went thru just to stay off the grid...and then selling out and getting a three minute drip thru Bunn...

I swore I'd never go back to boiling and perking...(even though I still grind my own beans from time to time)

I'll have to plug the Cuisinart into the truck to find out how long it actually takes..

[Squidd]

Also while we're on the subject of the coffee pot...

How do I do the math for power consumption to budget my usage...?

I assume 75 watt / 12 volt = 6.25 amp...??

And then to get amp/hrs I divide 6.25amp / 60 Minutes = .104 "amp/minutes"

And then multiply .104 "amp/mins * 4 minute brew time = .41 amp/hrs of power usage per pot...?

So with a 100 amp/hrs battery and 50% duty cycle I can get ~ 122 pots of coffee before recharge..?

I'm guessing at the formulas here...is it close or How should I figure my usage...?

[denverd0n]

You got the math right. Now just do that with everything on the boat that uses electricity and you've calculated your daily usage. Multiply by how many days you want to be able to go without recharging and you know how big of a battery to get. Simple.