Advice and Opinions Please DC and Shorepower System

Wiring your boat, How to Wire Lights/Accessories, All things electrical other than actually powering your boat by electric motors.

Moderator: Bill Edmundson

scout
Posts: 41
Joined: Sat Apr 27, 2013 8:48 am
Location: Chicago, IL

Advice and Opinions Please DC and Shorepower System

Post by scout »

I'm thinking about this for my shore power install:

http://www.ezacdc.com/boat-wiring-produ ... ore-power/

I'll have some led lighting, chartplotter, radio, fridge, air conditioning, and would like a built in battery charger.

specs for air conditioning:

power (volt/hz/ph) 115/60/1
full load amps -- cool 4.3
locked rotor amperage -- 14.0

fridge draws 3.0 amps DC

i'll have a separate starter battery.

will the system above be okay? recommendations for a built in battery charger? will a 200 amp/hr battery be enough, or should i go higher? air will only be shore power...fridge will be used constantly.

please feel free to respond as if you're talking to a child :oops:

User avatar
mrintense
Posts: 3902
Joined: Thu Jun 10, 2010 11:22 am
Location: Austin, Texas
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by mrintense »

If you haven't read it yet, consider purchasing the Electrical and Mechanical Systems book by Nigel Calder. This book is full of information that should help answer many of your questions. The title of the book may be slightly different from what I've stated here.
Carl

Crafting a classically styled Vera Cruise

User avatar
galamb
Posts: 838
Joined: Sat Jan 17, 2009 1:37 am
Location: Inverary, Ontario - Cuddy Sport (modified)
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by galamb »

The system on that link is no different than any marine shore power system available out there from any of the mfg's, it simply looks like they have packaged up a complete "small" system to easily retrofit an existing boat which did not have it from factory.

Depending on where you will be "plugging in" you could have 15, 20, or 30 amp 110/115 or 220 volt hook-ups dockside. Any of them would be sufficient to run your air conditioning unit while you are dockside and your on-board battery charger (unless you went pretty crazy with a massive unit).

To me (I played with their drop down choices) I find their system a little "pricey" for what it is - the attraction is that it's a full kit in a box.

To the second part of your question about how many amp hours for the house battery, you simply have to do a little math.

You say your fridge will burn 3 amps (per hour - no it doesn't run constantly (probably), but count it that way).

Then add up all the other things "on-board" that run on 12 volts - fishfinder, sonar, radar, lights, stereo etc (you can find the specs in their user manuals).

Then just add them all up according to how you will use them factoring in how long you will be on the water before you can get back to a source to recharge (don't forget your motor may be able to supply some recharging capacity - a small amount if it's a lower powered outboard, maybe all your needs if it's an inboard with an 80 amp alternator).

So as an example lets say you want to cruise an entire long weekend without touching land - 72 hours on the water -

Your fridge would be 3 x 72 = 216 amp hours
stereo or tv = 1 amp x 15 hours = 15 amp hours

(you get where I'm going here)

You could end up needing say 350 total amp hours over 3 days.

If your motor can provide say 16 amps per hour recharge capacity and you plan on running the boat 4 hours a day you can probably count on that to either run what needs running at that time or providing those amps to recharge the house battery.

That could give you 4 x 16 or 64 amp hours a day (max - 30 to 40 amps would be a safer bet).

For the sake of argument say 35 amps a day from the motor (in my example)

Total requirement = 350
Total replenishment = 105 (35 x 3 days running 4 hours a day)

Battery requirement for house battery 350-105 = 245 amp hours

Depending on the battery (or batteries) that use for your house load you may only want to discharge them to 50%, so in my example you may need a total of 500 amp hours of house batteries to meet the 50% discharge required to provide the 245 amp hours you could need.

Once you have "calculated" your 12 volt power requirements then you can determine what type of charger you need.

They come in every size and shape. If you end up with 3 house batteries with a total amp rating of say 600 amps, then a charger with 3 outputs that can totally recharge your batteries during an overnight at dockside would be in order.

If you were docked for 8 hours and needed to restore 50% of your 600 amps (300 amps) you would need 300 amps divided by 8 hours = 37.5 amps (40 amp) of charge capability (per hour) to totally "fill up" your batteries in an 8 hour period- so a "3 bank, 40 amp" charger would suit those particular needs...
Graham

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

scout
Posts: 41
Joined: Sat Apr 27, 2013 8:48 am
Location: Chicago, IL

Re: Advice and Opinions Please DC and Shorepower System

Post by scout »

galamb...

thank you! :D

i think i actually get it now.

User avatar
El Jefe
Posts: 42
Joined: Thu Sep 05, 2013 7:07 am
Location: Jefferson City, MO

Re: Advice and Opinions Please DC and Shorepower System

Post by El Jefe »

:idea:

Hope no one minds if I revive this thread.

I too have recently started down the path to figuring out a complete 12v DC system.
I intend to cruise the rivers here in the midwest, many of which have few facilities.
With that in mind I'm looking into a 12 volt system that could basically make one self sufficient while out cruising. My wife informs me that if she's going, she'll demand air conditioning, refrigeration and a TV. :?

Whatever I end up building (probably a tug cruiser) will be powered by a small diesel engine. I should be able to spin whatever alternator I end up thinking I need. I would think if your house bank is adequate and you can keep it charged, you should be able to do whatever you choose, assuming you have access to fuel.

Thus far I've bought the Boatowner's Illustrated Electrical Handbook by Charlie Wing. I've been reading and rereading sections of it each evening, I'll figure this all out eventually. :shock:

Anyone have any thoughts on 12 volt air conditioning and refrigeration units?

Rick

ps. great input already by galamb.

User avatar
Lowka53
Posts: 1938
Joined: Fri May 14, 2010 11:47 pm
Location: Ogden, Utah-Jubilee build
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by Lowka53 »

http://www.boatdesigns.com/Boatowners-M ... fo/12-490/ you probably should get this book it has what you are looking for in it. 8)
Don't be afraid to attempt anything. You might surprise your self in the attempt.
http://www.facebook.com/Home.Made.Boat.Building
Bon Voyage-"Wild Flower" 40' house boat being built
14' Mr John-being built
32' Supper Huck-in design

Rod H

Trackhappy
Posts: 1412
Joined: Wed Feb 17, 2010 5:42 pm
Location: Sunshine Coast, Queensland, Australia. Building Gentry.

Re: Advice and Opinions Please DC and Shorepower System

Post by Trackhappy »

There are 12 Volt A/C and fridges units available. Fridges are definitely do-able as the cooled space is tightly controlled and small, and then modern direct DC compressors are pretty efficient.
A/C units on the other hand are trying to cool quite a large cubic area, thus power requirements can be very high. Having said that, they do make them and I guess if you were running the main engine to keep the battery up then they would be useful.
Don't forget the sun and wind in all this. If you have some roof area, a couple 240 watt solar panels can out put a serious amount of energy, and in a windy area even a small wind turbine can provide useful power, but they are a little noisy in the smaller sizes.
By the time I have built a boat, I'll be ready to build a boat....

User avatar
El Jefe
Posts: 42
Joined: Thu Sep 05, 2013 7:07 am
Location: Jefferson City, MO

Re: Advice and Opinions Please DC and Shorepower System

Post by El Jefe »

Trackhappy, you make good points. So far I've looked at two different 12 volt AC systems, I need to look into those closely, I'd hate to end up with a piece of junk. As for refrigeration, the 12 volt/propane unit in our travel trailer works great. In fact if you're not careful it'll freeze everything in it in short order.

I dunno, obviously I need to do lots of reading and study. I'd like to have all the various systems figured out and the big pieces bought before I start making sawdust. I'm thinking if I have a diesel engine, a fridge, an AC unit and all the other stuff sitting there, I kinda have to follow through and get a boat built. :mrgreen:

User avatar
Lowka53
Posts: 1938
Joined: Fri May 14, 2010 11:47 pm
Location: Ogden, Utah-Jubilee build
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by Lowka53 »

El Jefe wrote:As for refrigeration, the 12 volt/propane unit in our travel trailer works great. In fact if you're not careful it'll freeze everything in it in short order.

I dunno, obviously I need to do lots of reading and study. I'd like to have all the various systems figured out and the big pieces bought before I start making sawdust. I'm thinking if I have a diesel engine, a fridge, an AC unit and all the other stuff sitting there, I kinda have to follow through and get a boat built. :mrgreen:
I don't know about other boats but I was informed by a site that deal with nothing but house boats that the coast guard banded propane refrigerators but i have as yet bee able to find the info for myself
Don't be afraid to attempt anything. You might surprise your self in the attempt.
http://www.facebook.com/Home.Made.Boat.Building
Bon Voyage-"Wild Flower" 40' house boat being built
14' Mr John-being built
32' Supper Huck-in design

Rod H

Trackhappy
Posts: 1412
Joined: Wed Feb 17, 2010 5:42 pm
Location: Sunshine Coast, Queensland, Australia. Building Gentry.

Re: Advice and Opinions Please DC and Shorepower System

Post by Trackhappy »

We are allowed them over here, but the "working part" of the fridge must be in a separate sealed compartment with the lowest point vented directly overboard. They are also prone to inefficiency when not level, which can be difficult on a boat.
By the time I have built a boat, I'll be ready to build a boat....

jcallends
Posts: 361
Joined: Tue May 26, 2009 4:46 am
Location: Coldwater Michigan

Re: Advice and Opinions Please DC and Shorepower System

Post by jcallends »

RV refrigerators are usually gas units with no moving parts, the gas is sulfur dioxide at about 300 psi. Heat from either a propane flame or an electric heater applied at the proper location causes the expansion of the gas, I believe liquefied, with the resulting absorption of heat. It is one of the oldest methods of refrigeration.

User avatar
galamb
Posts: 838
Joined: Sat Jan 17, 2009 1:37 am
Location: Inverary, Ontario - Cuddy Sport (modified)
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by galamb »

Depending on how you plan on using your boat you can go with a somewhat simpler refrigeration solution.

Since I only planned on needing it the odd weekend and maybe for a week long at most during vacation, as opposed to a "live aboard for a few months at a time", I opted for a (somewhat) portable unit from Coleman meant for weekend campers.

It burns 2 amps (12v) per hour, it does run all the time (it's really just an electric cooler, not a full blown fridge), it is about the size of an RV fridge and could be oriented as such - so with a bit of trim work it "looks" built in. The best part was it cost just a tic over 100 bucks (compared to the almost 2K for some recreational units).

With a bit of testing it does keep things "cold" enough to last a couple/few days.

I guess what I'm trying to get at is - think outside the box for your 12 volt stuff. There is a ton of stuff in the "auto" market now - coffee makers, coolers, hot plates etc - and because they are not RV or Marine the cost is less than 1/2...
Graham

Yes, Plywood is "real" wood :)

A "professional" is someone who gets paid for their work - it doesn't necessarily mean they are good at it :)

User avatar
Lowka53
Posts: 1938
Joined: Fri May 14, 2010 11:47 pm
Location: Ogden, Utah-Jubilee build
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by Lowka53 »

:lol: there has been a lot of progress in the 12v market of appliances made for truck drivers and all seem to be pretty sturdy do to the hard use they are built for.
Don't be afraid to attempt anything. You might surprise your self in the attempt.
http://www.facebook.com/Home.Made.Boat.Building
Bon Voyage-"Wild Flower" 40' house boat being built
14' Mr John-being built
32' Supper Huck-in design

Rod H

User avatar
raymacke
Posts: 751
Joined: Mon Apr 25, 2005 7:07 pm
Location: Marissa, IL
Contact:

Re: Advice and Opinions Please DC and Shorepower System

Post by raymacke »

I have a propane refrigerator installed in my True Grit and have now used it for three years totaling about 90 nights on-board and over 3000 miles. It has performed very well and for me it was the right choice. If I had a larger boat (36'+) with built-in generator I "might" consider electric but even then it would be a tough call for me. We love the peace and quiet - don't want to listen to an engine droning on and on all day and night. And 12 refrigerators do eat the amps. I can't even fathom trying to keep up with a 12v A/C unit. Be prepared for large battery banks and hours of engine running time to keep them charged.

Don't be confused about having a 100 or 150 amp alternator and thinking you can just run it and hour or so and quickly recharge the batteries. The amount of amps you can safely charge at is dependent on the size of you bank (amp hours). Another words you can't take a single 12v discharged battery and hit it with 100 amps for 30 minutes or and hour and bring it back to full charged. You will end greatly reducing its life span if not cooking it. High amp chargers or alternators allow you to charge larger banks - not faster. Maintaining healthy battery banks require lower amperage charging for multiple hours. Using smart multi stage charger with a temperature sensor can speed this up some but still requires hours.

I guess my point is if you are planning on both 12v refrigeration and a/c it wouldn't surprise me if you have to run your engine 40% of the time your on the boat.

I have a few thoughts on my propane system near the bottom of this page - http://www.egyptian.net/~raymacke/TG/Impress.html But I am no expert. I made the decisions based on my own research and what I though was best for "my" situation and yours may well be different.
So Many Rivers,
So Little Time....

User avatar
El Jefe
Posts: 42
Joined: Thu Sep 05, 2013 7:07 am
Location: Jefferson City, MO

Re: Advice and Opinions Please DC and Shorepower System

Post by El Jefe »

Ray, you make some salient points. :idea:

A three stage charger is a must, especially considering how expensive decent batteries are. It also appears to me that a good regulator/monitor is important so you don't discharge your house bank too much. The more I've looked into this the more interesting, not to mention complex, I realize these systems are, if they are to work properly over time.

As usual, there's no free lunch!

Post Reply

Return to “Electric Power & Systems”