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Therapy · 25-07-2013, 14:09

Quote:

Originally Posted by barnakiel

Last summer I worked on a boat where really big engines were started from toilet rolls. Single one per each engine. This boat sails in cold climates, no issues starting ever.

b.

I was looking for the argument in not needing a dedicated start battery and came across this.

WHAT!!

SVTatia · 25-07-2013, 14:20

Quote:

Originally Posted by Therapy

I was looking for the argument in not needing a dedicated start battery and came across this.

WHAT!!

For the argument you are seeking: I decided not to have a dedicated start battery after reading this excellent post by Maine Sail:

1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

Makes perfect sense if you manage your batteries well.

Mystic38 · 27-07-2013, 06:08

personally i see that simply a semantic difference... ?..

IMO if you have two house banks and hold one bank for starting reserve using the 1/2/all/off switch then you effectively have a House + Start setup.

I have two banks... bank #1 is three grp 31 and is the house; bank #2 is a single grp27 and is considered the engine start battery.
Now high quality vessels that have two banks typically have two 1/2/all/off switches, one for house source and one for engine start source.

My boat, like most, has a single 1/2/all/off switch however I believe my wiring is superior to that shown in the article in that the engine starter feed goes direct from the bank #2 terminal (via an isolator) to the starter. The improvement here is that :
a) the 1/2/all/off switch has not moved from "1" in 5 years, (hence removal of operator error, and no battery management required)
b) bank #2 is dedicated start bank and sized appropriately (ie small)
c) Original purpose of 1/2/all/off switch (house feed selection) is maintained
d) house is isolated from starting surges in all normal start situations

my system of course is capable of charging both banks either from engine, solar or charger.

Quote:

Originally Posted by SVTatia

For the argument you are seeking: I decided not to have a dedicated start battery after reading this excellent post by Maine Sail:

1/BOTH/2/OFF Switches Thoughts & Musings - SailboatOwners.com

Makes perfect sense if you manage your batteries well.

Windswept40 · 29-07-2013, 07:57

The pros behind having all Golf cart is that the require the same charge type and all have similar charging properties. I have a 40' with 2 sets of golf carts for the house bank and a dedicated starting battery. I have a high output alternator/3-stage reugulator that charges the house bank. I have an Echo charger that charges the starting battery. So under way my alternator/regulator is set to optimize charging of the house bank and I don't risk overcharging the starting battery. I have the battery switches wired so that I can isolate the start battery and run totally off of the house bank including being able to start from the house bank. This is how we leave it when we are off the dock. If the house bank runs to low I can switch in the starting battery, which in the last 3 years I have never had to do. The only caveat to this sysytem is that I have to be aware of voltage drops on the electronics when we start from the house bank. Garmin GPS never has an issue but the older Raymarine radar/Plotter has restarted.

So you in my opinion if the system worked with all GC batteries without any problem then why change.

SVTatia · 29-07-2013, 12:05

Quote:

Originally Posted by Mystic38

personally i see that simply a semantic difference... ?..

IMO if you have two house banks and hold one bank for starting reserve using the 1/2/all/off switch then you effectively have a House + Start setup.

I have two banks... bank #1 is three grp 31 and is the house; bank #2 is a single grp27 and is considered the engine start battery.
Now high quality vessels that have two banks typically have two 1/2/all/off switches, one for house source and one for engine start source.

My boat, like most, has a single 1/2/all/off switch however I believe my wiring is superior to that shown in the article in that the engine starter feed goes direct from the bank #2 terminal (via an isolator) to the starter. The improvement here is that :
a) the 1/2/all/off switch has not moved from "1" in 5 years, (hence removal of operator error, and no battery management required)
b) bank #2 is dedicated start bank and sized appropriately (ie small)
c) Original purpose of 1/2/all/off switch (house feed selection) is maintained
d) house is isolated from starting surges in all normal start situations

my system of course is capable of charging both banks either from engine, solar or charger.

Semantics all right - I have house and reserve. I start the engine using house only. The alternator wire goes to house, the starter to "C" post. The reserve is only used when and if needed. I have an ACR between house and reserve. The 1/2/both/off is used on 1 (house) all the time when on the boat, and off when out. It is just that - an on/off switch.

JK n Smitty · 29-07-2013, 12:18

Quote:

Originally Posted by SVTatia

Semantics all right - I have house and reserve. I start the engine using house only. The alternator wire goes to house, the starter to "C" post. The reserve is only used when and if needed. I have an ACR between house and reserve. The 1/2/both/off is used on 1 (house) all the time when on the boat, and off when out. It is just that - an on/off switch.

I have the same setup and endorse this as much better than the traditional stock setup or the dedicated starter battery.

Mystic38 · 30-07-2013, 01:57

Some food for thought ......

Our two setups are more similar than different, with alternator and charging feeds to a large house bank #1 then (insert rollover charging method here) to a smaller Bank #2...
The sole difference is where the two setups take the start feed from. In my case its from bank #2 direct and in your case bank #1 via the C post..

So we have essentially house+start or house+reserve based upon where the start feed originates...agreed?

here is the rub..

When you have a house+start you know and test the condition of the smaller bank #2 daily/whenever by starting the engine. Any indications of deteriorating condition of the start battery can be quickly spotted.

When you have a house+reserve, bank #2 is left unused and is simply assumed to be in good condition (given you never test the condition of the smaller bank #2). The only time this bank is engaged is in an emergency...

So, in one vessel a captain knows the condition of bank #2 and in another the captain assumes the condition of bank #2...

so which is a more robust setup?

Quote:

Originally Posted by JK n Smitty

I have the same setup and endorse this as much better than the traditional stock setup or the dedicated starter battery.

JK n Smitty · 30-07-2013, 03:06

Quote:

Originally Posted by Mystic38

Some food for thought ......

Our two setups are more similar than different, with alternator and charging feeds to a large house bank #1 then (insert rollover charging method here) to a smaller Bank #2...
The sole difference is where the two setups take the start feed from. In my case its from bank #2 direct and in your case bank #1 via the C post..

So we have essentially house+start or house+reserve based upon where the start feed originates...agreed?

here is the rub..

When you have a house+start you know and test the condition of the smaller bank #2 daily/whenever by starting the engine. Any indications of deteriorating condition of the start battery can be quickly spotted.

When you have a house+reserve, bank #2 is left unused and is simply assumed to be in good condition (given you never test the condition of the smaller bank #2). The only time this bank is engaged is in an emergency...

So, in one vessel a captain knows the condition of bank #2 and in another the captain assumes the condition of bank #2...

so which is a more robust setup?

Well, your question assumes that I don't regularly test and start from my reserve bank. I do that once a week as part of my weekly run of the engine while I check for leaks and other potential problems (every Sunday morning after breakfast. It also heats up water to do the dishes). You probably don't have to be as anal as I am about checking but you do need some personal responsibility to check that battery (our monitor is only hooked to the house bank. I could have gone with a dual bank monitor but they were twice the money). On our boat that is done by a simple flip of a switch at the panel to read the voltage in bank two.

The difference of the house plus start vs the house plus reserve is that if say I run down my house, I can still have things like VHF or nav instruments when switch over.

When your starter is dead what do you do? Do you have a cross over to let you start from the house bank?

SVTatia · 30-07-2013, 10:21

Quote:

Originally Posted by SVTatia

...Makes perfect sense if you manage your batteries well.

As per my quote above - Post # 17

Quote:

Originally Posted by JK n Smitty

Well, your question assumes that I don't regularly test and start from my reserve bank. I do that once a week as part of my weekly run of the engine while I check for leaks and other potential problems (every Sunday morning after breakfast. It also heats up water to do the dishes). You probably don't have to be as anal as I am about checking but you do need some personal responsibility to check that battery (our monitor is only hooked to the house bank. I could have gone with a dual bank monitor but they were twice the money). On our boat that is done by a simple flip of a switch at the panel to read the voltage in bank two.

The difference of the house plus start vs the house plus reserve is that if say I run down my house, I can still have things like VHF or nav instruments when switch over.

When your starter is dead what do you do? Do you have a cross over to let you start from the house bank?

++1

Mystic38 · 30-07-2013, 17:38

JK..

I think you are misunderstanding a little how I am suggesting a better wiring is done..
a) bank 1 goes to bank 1 on 1/2/off/all switch (switch normally=1)
b) bank 2 goes thru isolator switch (normally=on) to bank 2 on 1/2/off/all switch
c) the house is still fed from the center post of the 1/2/all/off switch, hence bank 2 is still available as house reserve.
d) bank 2 from the 1/2/off/all switch is wired direct to the starter (not from center post).
e) in the event of a weak start battery the house switch can be set to "all" to allow engine start from the house battery.
f) in the highly unlikely event of a dead start battery, bank 2 isolator switch may be set to off (to electrically isolate the two banks), then 1/2/off/all is set to "all".
g) an additional benefit of the isolator is that the engine dc supply can be disconnected for maintenance without disrupting house supply (lighting etc)

regards, Ian

Quote:

Originally Posted by JK n Smitty

The difference of the house plus start vs the house plus reserve is that if say I run down my house, I can still have things like VHF or nav instruments when switch over.

When your starter is dead what do you do? Do you have a cross over to let you start from the house bank?

@svtatia..
having a dedicated second bank (battery) as engine start eliminates the requirement that the house batteries need to be "well managed" and also eliminates the requirement to regularly check the unused reserve bank for performance.
In my posts I have provided several fundamental engineering reasons why the wiring can be improved upon from a house+reserve to house+start. So while i would value any technical insight you can offer as part of a discussion, simply giving yourself a +1 does in no way provide any engineering basis to support one wiring system over another

..

SVTatia · 30-07-2013, 18:01

Quote:

Originally Posted by Mystic38

JK..
...
@svtatia..
...simply giving yourself a +1 does in no way provide any engineering basis to support one wiring system over another

..

Mystic

I ain't no engineer, I just indicated that I agreed with JK, a normal thing to do. I appreciate your suggestions and I am glad your wiring arrangement works for you.
Enjoy the season and best regards. - SVTatia over and out

Maine Sail · 30-07-2013, 18:59

Unfortunately there is no "right way". Everyone prefers something different. There are piles of switch and battery configurations out there and they all work and I've wired them all ways from Sunday.

*The vast majority of my customers like their 1/2/BOTH and have used it successfully for 20-30 years or more and in most instances doing everything off the house bank including starting. Many of them never test the "reserve battery" but a number of them have had to use it and I can't recall any of them who did not get the engine to fire. Many have supplemented these switches and converted them from charge directing/use to a use only switch by adding a charge management device such as an Echo Charger or combining relay or, years ago, a battery isolator.

*Some of my customers like the 1/2/BOTH with an added On/Off for dedicated engine starting. This works well too.

*Some of my customers will only have a three On/Off system: On/House, On/Engine, On/OFF/Combine/Isolate

*Some love their Blue Sea Dual Circuit Switch

All these systems work none of them is any more right than the other except to the owner. Cases can be made for or against almost all of them but in the end it is what ever floats your boat and helps you sleep at night.

My case is usually: keep it simple, keep it redundant, keep the ability to 100% isolate a bad bank if necessary and run everything from the other. There are many ways to skin that Cat.

On my own boat I have a LiFePO4 lithium house bank and a AGM "reserve" bank. The LiFePO4 does it all via a 1/2/BOTH used as an On/Off switch. Simple, easy & has redundancy. Even at 80% DOD the LiFePO4 has thousands more cranking amps than my 100% SOC AGM. Why would I subject my starter to the voltage drop of an LA battery when I can feed it vicious starting current and only ever touch one switch to turn it on and off. Works for me but maybe not others...