Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 11-02-2018, 16:07   #1
Registered User

Join Date: Jun 2010
Location: Easton, MD
Boat: Catalina 22 Capri
Posts: 1,285
Feasibility of Large Battery Banks

Don't 12V battery banks over 500 Ah become less attractive than a generator? The weight and complexity of charging large banks and the ability of a generator to run AC seems to favor generators instead of large battery banks.
__________________

__________________
kmacdonald is offline   Reply With Quote
Old 11-02-2018, 17:27   #2
Senior Cruiser
 
StuM's Avatar

Cruisers Forum Supporter

Join Date: Nov 2013
Location: Port Moresby,Papua New Guinea
Boat: FP Belize Maestro 43
Posts: 6,869
Re: Feasibility of Large Battery Banks

I'd much rather have my 800W of solar and 1000Ah of batteries than a generator
__________________

__________________
StuM is offline   Reply With Quote
Old 11-02-2018, 18:13   #3
Registered User

Join Date: Nov 2011
Location: On Evenstar
Boat: Hallberg-Rassy 53
Posts: 130
Send a message via Skype™ to Evenstar
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by kmacdonald View Post
Don't 12V battery banks over 500 Ah become less attractive than a generator? The weight and complexity of charging large banks and the ability of a generator to run AC seems to favor generators instead of large battery banks.
I'm not sure that makes any sense. Nobody wants to listen to a generator runnning all the time. The loads a boat uses are quite light compared to what even the tiniest generator puts out. It's really inefficient to run even a dinky 1Kw Honda noisemaker to service even 15A (180W) worth of house lights and refrigeration. Better to run the goddamnednoisybox to charge up your batteries in a couple of hours then enjoy the quiet.

We've got 720Ah @24V of LiFePO4 batteries. Works just fine with a 7Kw generator running every three days or so for about 5 hours. We can invert for all the AC we need.
__________________
S/V Evenstar - Hallberg-Rassy 53 Hull #34
Our travel blog, or "Embarrassing things I do to myself around boats"...
Evenstar is offline   Reply With Quote
Old 11-02-2018, 18:14   #4
Registered User

Join Date: Nov 2011
Location: On Evenstar
Boat: Hallberg-Rassy 53
Posts: 130
Send a message via Skype™ to Evenstar
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by StuM View Post
I'd much rather have my 800W of solar and 1000Ah of batteries than a generator
Me too, but I don't have decent deck space for it without reworking a lot of stuff.
__________________
S/V Evenstar - Hallberg-Rassy 53 Hull #34
Our travel blog, or "Embarrassing things I do to myself around boats"...
Evenstar is offline   Reply With Quote
Old 11-02-2018, 18:25   #5
Registered User

Join Date: Jun 2010
Location: Easton, MD
Boat: Catalina 22 Capri
Posts: 1,285
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by Evenstar View Post
Me too, but I don't have decent deck space for it without reworking a lot of stuff.
Cats seem to have the space for solar but monos don't without making it look hideous.
__________________
kmacdonald is offline   Reply With Quote
Old 11-02-2018, 18:43   #6
Registered User

Join Date: Feb 2009
Posts: 1,862
Re: Feasibility of Large Battery Banks

I have over 1100 watts of solar, and over 1200 amp hours of battery
I mainly run my generator to make hot water for the shower. Even in the winter I am 90% sufficient in the summer there is no question
__________________
motion30 is offline   Reply With Quote
Old 12-02-2018, 01:39   #7
Registered User

Join Date: Nov 2017
Location: On the Water
Boat: 53' Cutter
Posts: 136
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by kmacdonald View Post
Don't 12V battery banks over 500 Ah become less attractive than a generator? The weight and complexity of charging large banks and the ability of a generator to run AC seems to favor generators instead of large battery banks.
"run AC"?

Do you mean run A/C (air conditioning) or run AC power? Big difference.

There is no complexity in charging large battery banks unless you have many small batteries comprising the bank. If you need to generate AC power for short periods of time, a quality inverter will do the job.

If you need to generate significant AC power over long periods of time, then a generator is usually the best option. But if you are wanting a generator in order to run A/C (air conditioning), just remember that A/C is called "generator eaters" for a reason. If you cannot keep your generator loaded up when it is running, it will have a short lifespan.
__________________
SailsWithFists is offline   Reply With Quote
Old 12-02-2018, 04:43   #8
Registered User

Join Date: Apr 2013
Posts: 5,201
Re: Feasibility of Large Battery Banks

500amp-hr of lead-acid batteries is only about 3kwh of usable power if you start out fully topped up. Less if you only got back up to 80% full the day before.

Generators are really best to handle big loads like air/con. They are pretty limited for battery charging as once you hit 80-90% charge, the charge acceptance by the batteries drops off quickly.

If you aren't running the air/con or similar, solar can keep up nicely with that battery bank and reasonable loads.
__________________
valhalla360 is offline   Reply With Quote
Old 12-02-2018, 05:21   #9
Registered User

Join Date: Aug 2015
Location: Marina del Rey
Boat: Hunter 31
Posts: 486
Re: Feasibility of Large Battery Banks

Power generation is the key, not battery capacity. It is either solar, portable gas gen, diesel gen or engine. I am still amazed at people who size their batteries to handle 4-5 cloudy days when you can easily run the engine Midway and be done with it.

The problem with batteries over 5-600 AHrs is that they are heavy and serve no need on a typical sailboat.

An inverter helps with short loads but if you use aircon, electric pressure cooker or electric heat, it is a non-starter. I agree with you that a small portable genny is much more useful than solar charging, discharging, heat, inverter fan noise and the other issues with high current applications. For a larger boat, a diesel genny.
__________________
Pizzazz is offline   Reply With Quote
Old 12-02-2018, 06:06   #10
Registered User
 
ranger42c's Avatar

Join Date: Aug 2012
Location: Maryland, USA
Boat: 42' Sportfish
Posts: 3,060
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by kmacdonald View Post
Don't 12V battery banks over 500 Ah become less attractive than a generator? The weight and complexity of charging large banks and the ability of a generator to run AC seems to favor generators instead of large battery banks.

I don't look at generator and battery bank as an either/or proposition.

Our genset will run our aircons and electric cooktop, heat water, charge batteries... and when we power lighter loads, the batteries do fine, quietly... for a while.

IOW, we use both, as appropriate for our purposes.

Certainly boat size and usage would guide, though...

-Chris
__________________
Selby Bay, South River, Chesapeake Bay, USA.
ranger42c is offline   Reply With Quote
Old 12-02-2018, 06:38   #11
rom
Registered User

Join Date: Mar 2016
Boat: Lagoon 440
Posts: 381
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by Pizzazz View Post
Power generation is the key, not battery capacity.
Could be for you. For me they are two keys of a complex mix which doesn't work the same from january to december, where the boat is, how many people are onboard.
Quote:
Originally Posted by Pizzazz
The problem with batteries over 5-600 AHrs is that they are heavy and serve no need on a typical sailboat.
If a typical sailboat is a 31' monohull that is being used as you use it, then maybe you right.
__________________
rom is offline   Reply With Quote
Old 12-02-2018, 06:51   #12
Don't ask if you can't handle it
 
sailorboy1's Avatar

Cruisers Forum Supporter

Join Date: Jul 2007
Location: On the boat somewhere
Boat: Hunter 410
Posts: 12,576
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by StuM View Post
I'd much rather have my 800W of solar and 1000Ah of batteries than a generator
So would I and I have a generator. But a generator is still worth having.
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is online now   Reply With Quote
Old 12-02-2018, 07:19   #13
Registered User

Join Date: Nov 2016
Location: Uk Rye
Boat: Moody 44’ ketch
Posts: 19
Feasibility of Large Battery Banks

Can’t someone tell the scientists to hurry up with the solar sails?
We need ‘em cheap and we need ‘em now
__________________
Malabarista is offline   Reply With Quote
Old 12-02-2018, 07:22   #14
Registered User

Join Date: Jan 2017
Location: Everywhere
Posts: 267
Re: Feasibility of Large Battery Banks

Quote:
Originally Posted by Pizzazz View Post
The problem with batteries over 5-600 AHrs is that they are heavy and serve no need on a typical sailboat.
You say that as if generators and the fuel they consume don't also have significant weight and take up significant space.

They're also significantly more complex, require routine maintenance, and increase trips to the fuel dock.

Personally I'd rather fill a generator locker with batteries.
__________________
LoudMusic is offline   Reply With Quote
Old 12-02-2018, 09:28   #15
Registered User
 
S/V Alchemy's Avatar

Join Date: May 2008
Location: Toronto
Boat: Custom 41' Steel Pilothouse Cutter
Posts: 4,637
Re: Feasibility of Large Battery Banks

Mine are quite feasible. 1,575 Ah over six L-16s deep cycle FLA batteries in series-parallel. Right under the mast with a set of companionway stairs over 'em. Charging is via wind (300w) and solar (135w x 4 on an arch) and, soon, a 250 A alternator for "equalization underway". Oh, and a couple of Honda 2000s should I experience a failure (or need to operate power tools ashore).

The point was to stay as much as possible in the high end of SOC (75% or over). That meant sizing for anticipated use (daily drawdown) and working within that "band". I do not want a typical below-decks genset, but portables ganged are fine, because I use those for other things. I do not wish to run the auxiliary diesel just to make power, but when I do run it, I want to get as high an acceptance rate as I can when doing runs like "motoring out to the three-mile limit for pump-outs".

A lot of my ideas come from homesteaders, who've basically solved these issues already. I realize that most production boats don't want to haul 320 kilos of batteries, but I have a custom pilothouse in steel (see picture to left). Putting the batteries in has actually stiffened the boat up. The only thing I would recommend is taking a full-systems approach, starting with an honest appraisal of how much power you need and the importance of shore-independence to you. Other decisions, like solar/wind capacity, charger/inverter selection, and even wiring and fuse sizing, proceed from that initial appraisal of what you'll be safe with in terms of minimums (keep the nav lights and radio working) and what you'll be happy with in terms of amenities (hot water, "movie night" and ice cubes after three days of cloudy and calm weather). https://alchemy2009.blogspot.ca/2016...wering-up.html
__________________

__________________
Can't sleep? Read www.alchemy2009.blogspot.com for fast relief. Can't read? Avoid www.volumesofsalt.blogspot.com, because it's just personal reviews of sea books.
S/V Alchemy is offline   Reply With Quote
Reply

Tags
battery

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
feasibility of variable length hull/variable beam cat... black_sails Multihull Sailboats 15 04-05-2016 09:11
Feasibility of an Atlantic Circuit on a very short Sabbatical? Dockhead Atlantic & the Caribbean 29 03-12-2012 17:54
Question About Feasibility Star Journey Monohull Sailboats 0 12-07-2010 15:57
Battery Bank. two banks or one rsn48 Electrical: Batteries, Generators & Solar 16 07-06-2007 18:17



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 19:00.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2018, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.