Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 30-03-2016, 13:03   #1
Registered User

Join Date: Sep 2015
Location: Hailey, ID
Boat: Gulf 32 & Nimble 20
Posts: 348
Always on devices - house or starter battery?

Currently have a few "always on" devices (buzzers for high water temp, low oil pressure, high water alarm, bilge pump) currently hard wired to the start battery, going to be moving these off the batteries and onto a bus bar / fused block.

My question is, what should I be connecting my fuse block to? Keep in mind, these are things I do NOT want to have switched on any panel anywhere as I want them to be always hot (well bilge pump #1 has its own switch but it's hidden away from sticky fingers).

Seems my options are:
1) Connect to start battery... it's more likely to have full charge than house, and less likely to be accidently drained, but it's only one battery and therefore much less capacity.
2) Connect to house bank... three deep cycle(ish) batteries instead of one, so that's a plus, but they are conceivably more likely to run dead some day from an overacting fridge etc. etc.
3) I guess I could connect to the 1->2 battery switch and then my always on appliances just go from wherever the battery switch is set, but not sure I like this as it makes it possible to turn off these things I want always on.

Is there a set way of doing this? Are my three choices above not the brightest ideas?

-- Bass
__________________

__________________
basssears is offline   Reply With Quote
Old 30-03-2016, 13:13   #2
Registered User
 
Dave-Zim's Avatar

Join Date: Nov 2015
Location: Zimbabwe
Boat: Calypso Cat 21'
Posts: 44
Re: Always on devices - house or starter battery?

Hey Bass.

I would connect to house bank and invest in a device to disconnect your house bank from normal loads when battery voltage drops to a set level. 12.2v or similar.
That way, you have the safety of the critical loads being connected to the largest battery bank. Also, you would have the added safety of your house bank never being totally flattened.

Low voltage disconnects aren't huge money and would give you peace of mind I think.
obviously critical loads would bypass the disconnect.

Dave
__________________

__________________
Dave-Zim is offline   Reply With Quote
Old 30-03-2016, 13:30   #3
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Always on devices - house or starter battery?

My opinion only.
Connect to house battery. Do not use low voltage disconnect.

My personal reasoning:
1. I always want the ability to start the engine-it could get my sinking boat to a beach,where salvage is more feasible.

2. I would rather flatten my house bat.,or even ruin it,than have the boat sink.

3. Items that I don't want turned off (B pump,fume alm,etc. are safety items.
I have to actually remove a fuse to de-power them. No chance of accidental disconnect. I won't even use a switch style breaker.

Paranoid ? Probably,but I sleep better.

Here is a basic diagram.

https://www.dropbox.com/s/l7fuzp9c45...ching.pdf?dl=0
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 30-03-2016, 13:42   #4
Registered User
 
Dave-Zim's Avatar

Join Date: Nov 2015
Location: Zimbabwe
Boat: Calypso Cat 21'
Posts: 44
Re: Always on devices - house or starter battery?

Quote:
Originally Posted by deblen View Post
My opinion only.
Connect to house battery. Do not use low voltage disconnect.

My personal reasoning:
1. I always want the ability to start the engine-it could get my sinking boat to a beach,where salvage is more feasible.

2. I would rather flatten my house bat.,or even ruin it,than have the boat sink.

3. Items that I don't want turned off (B pump,fume alm,etc. are safety items.
I have to actually remove a fuse to de-power them. No chance of accidental disconnect. I won't even use a switch style breaker.

Paranoid ? Probably,but I sleep better.

Here is a basic diagram.

https://www.dropbox.com/s/l7fuzp9c45...ching.pdf?dl=0
Low voltage disconnect is there to ensure non critical loads....like fridges and lights, are disconnected BEFORE battery is flat. This ensures there is enough energy kept in the batteries so that critical loads are guaranteed a reasonable amount of power so they can continue to work. Critical loads will still be able to run to the bitter end. The LVD just ensures they have the best chance of doing so.
__________________
Dave-Zim is offline   Reply With Quote
Old 30-03-2016, 13:44   #5
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: 12,310
Re: Always on devices - house or starter battery?

I connect my "always on" loads to the house battery. My thinking is that if they drain the house battery I still want to be able to start the engine, and that if the house battery were to be drained by the load that the small start battery is a drop in the bucket.
__________________
jobless, houseless, clueless, living on a boat and cruising around somewhere
sailorboy1 is offline   Reply With Quote
Old 30-03-2016, 13:52   #6
Registered User

Join Date: May 2014
Boat: Morgan Out Island 41
Posts: 701
Images: 2
Re: Always on devices - house or starter battery?

Bilge pump and VHF should be wired to the house battery ALWAYS! the house bank almost always has far greater capacity than the start battery. the rest can stay on the start battery as they're only relevent when the engine is running and therefore charging the start and house batteries
__________________
pcmm is offline   Reply With Quote
Old 30-03-2016, 14:03   #7
Registered User

Join Date: Sep 2014
Location: Santa Eulalia, Ibiza
Boat: Binliner 195
Posts: 60
Re: Always on devices - house or starter battery?

Quote:
buzzers for high water temp, low oil pressure,
Usually on ignition switched feed ?

Tim
__________________
blackswan555 is offline   Reply With Quote
Old 30-03-2016, 14:22   #8
Registered User

Join Date: Apr 2013
Location: So Cal
Boat: Catalina 30
Posts: 943
Re: Always on devices - house or starter battery?

It may very likely depend on the usage of your boat. Mine is a weekender. My #1 priority is the bilge pump. So I've got the bilge pump wired to both the main and the backup batteries with a couple of diodes. It'll run off of whatever battery has the most voltage in it.

Yes, that does mean I can flatten both batteries with the bilge pump. That's OK by me because if I'm on the boat I'd notice it way before that. If I'm off the boat I want the pump running if it needs to.

My CO detector runs on AA's.

Those are the only 2 things that are always on.
__________________
jeepbluetj is offline   Reply With Quote
Old 30-03-2016, 14:48   #9
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Always on devices - house or starter battery?

Quote:
Originally Posted by Dave-Zim View Post
Low voltage disconnect is there to ensure non critical loads....like fridges and lights, are disconnected BEFORE battery is flat. This ensures there is enough energy kept in the batteries so that critical loads are guaranteed a reasonable amount of power so they can continue to work. Critical loads will still be able to run to the bitter end. The LVD just ensures they have the best chance of doing so.

Ahh Good plan!
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 30-03-2016, 15:34   #10
Registered User
 
Dsanduril's Avatar

Join Date: Aug 2011
Location: South Pacific
Boat: Outremer 50S
Posts: 1,451
Re: Always on devices - house or starter battery?

If you really want the belt-and-suspenders approach, connect them to both battery systems. The cheap way is a couple of diodes of the appropriate size in the line, seeking those that have the lowest voltage drop.

The expensive way is get yourself a MOSFET-based power supply redundancy module (and the intermediate way is a pre-manufactured diode-based redundancy module). Redundancy modules are standard equipment in many industries, finding one that you would be satisfied with in the marine environment would be the time-consuming part.
__________________
Dsanduril is offline   Reply With Quote
Old 30-03-2016, 15:38   #11
Registered User

Join Date: Sep 2015
Location: Hailey, ID
Boat: Gulf 32 & Nimble 20
Posts: 348
Re: Always on devices - house or starter battery?

Thanks everyone, this definitely helped clear up my thinking. Lots of good ideas here... what has solidified for me is:

1) Connect my critical "always on" devices to fused bus bar connected directly to house bank.
2) Put low voltage disconnect between house bank and panel (so non essentials can't kill batteries, but essentials could still use all of battery if they needed to (your point is well taken Deblen). Probably use Blue Sea m-LVD, seems solid. Thanks for this Dave, wasn't familiar with these.

Crude schematic attached...

Off to Defender's sale I guess
Attached Thumbnails
Click image for larger version

Name:	Battery overall.png
Views:	134
Size:	15.2 KB
ID:	121690  
__________________
basssears is offline   Reply With Quote
Old 30-03-2016, 21:46   #12
Registered User
 
deblen's Avatar

Join Date: Oct 2014
Location: Grand Manan,N.B.,Canada N44.40 W66.50
Boat: Mascot 28 pilothouse motorsailer 28ft
Posts: 1,400
Images: 1
Re: Always on devices - house or starter battery?

Link to Lo Volt disconnect Blue Sea m-LVD Low Voltage Disconnect
__________________
My personal experience & humble opinions-feel free to ignore both
deblen is offline   Reply With Quote
Old 31-03-2016, 00:24   #13
Registered User

Join Date: Jun 2013
Location: canada
Posts: 1,698
Re: Always on devices - house or starter battery?

your engine things (oil pressure, temp etc, should be on the engine battery. and have no reason to be unswitched. infact they should probably be ignition controlled.




the bilge pump and high water should be on house unswitchd.
__________________
smac999 is offline   Reply With Quote
Old 31-03-2016, 00:53   #14
Registered User
 
Swift Drift's Avatar

Join Date: Oct 2011
Location: ORYGUN
Boat: Catalina 34, Merit 25
Posts: 86
Re: Always on devices - house or starter battery?

Quote:
Originally Posted by smac999 View Post
your engine things (oil pressure, temp etc, should be on the engine battery. and have no reason to be unswitched. infact they should probably be ignition controlled.




the bilge pump and high water should be on house unswitchd.

This! I had my engine panel wired to my house batteries which powers gauges/alarms and.....wait for it...Glow plugs!!!
I ended up learning the hard way that this was not a great configuration. Had house batteries that were failing and was unable to start my boat. Determined that weak house batteries weren't pumping enough juice to glow plugs. Would have never known and likely never had a problem had house batteries been healthy.
But.....in my mind, having glow plugs underpowered effectively produces the same result as a starter that's underpowered...no start! Luckily I was able to work through the problem with some annoyance rather than being thrust into a dangerous situation. Could have very well put me in a dangerous situation had circumstances been different though.
__________________
Swift Drift is offline   Reply With Quote
Old 31-03-2016, 03:38   #15
Registered User

Join Date: Apr 2006
Posts: 4,413
Re: Always on devices - house or starter battery?

These always on should not drain your house bank.... unless you have no charging... as in solar, wind or shore power.... and leave the boat for a long time. It doesn't take much in solar to supply what the always on consume... unless you have a bilge pump which draws a lot and runs a lot. Items such as the Link battery monitor draw little and usually are powered by the House bank.

I vote house.
__________________

__________________
Sandero 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
Advice on Adding Starter Battery waterwks4me Electrical: Batteries, Generators & Solar 18 11-08-2015 10:36
Simple question about conecting solar panels to a house and seperate starter batteryy SurferShane Electrical: Batteries, Generators & Solar 4 05-03-2015 04:48
How would you wire a starter battery-house bank connection earthbm Electrical: Batteries, Generators & Solar 21 27-08-2013 00:29
New Starter Battery nigellongland Electrical: Batteries, Generators & Solar 24 13-08-2012 13:54
Charging a Dedicated Starter Battery and House Bank Ericsn25Chespk Electrical: Batteries, Generators & Solar 8 02-09-2010 08:44



Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 02:26.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.