Re: Stus-List Practical installation of ACR/VSR

[Joe Della Barba via CnC-List]

My ACR is so close to the battery connections I am not fusing it. The wire
runs are literally about 4 inches.

Joe Della Barba
j...@dellabarba.com

Coquina
C 35 MK I
-Original Message-
From: CnC-List [mailto:cnc-list-boun...@cnc-list.com] On Behalf Of
Syerdave--- via CnC-List
Sent: Sunday, July 10, 2016 8:17 AM
To: C Stus List <cnc-list@cnc-list.com>
Cc: syerd...@gmail.com
Subject: Stus-List Practical installation of ACR/VSR

Hello all,
Wondering about the practical vs the theoretical here.  
Am upgrading the DC system, adding a Group 24 dedicated start battery, and
connecting the two group 31 in parallel to double the capacity of what will
become the dedicated house bank.   Am adding a blue sea switch and ACR.
FYI - an ACR is a device that upon starting the engine essentially 'chooses'
to top up the start battery fully before allowing the the house bank to be
charged.   
Anyway, the manual states that the acr should be connected as close as
possible to the battery (to prevent voltage drop from compromising its
function to any degree) and both of its leads fused based on the wire gauge.
All makes sense, especially when the batteries are located At a distance
from the switch or ACR.   however
The simplest installation is directly adjacent to the switch, not the
battery.  The leads to the ACR would be very short and well protected - less
than a foot.  (The battery cables themselves are not fused!)  In the 33-2,
the distance to battery is still very short - less than eight feet of cable
for sure.

In this situation, I can only see an infinitesimal difference in voltage
drop by locating the ACR a few feet closer to the battery, really, no
meaningful difference.  With a lead length measured in inches the positive
wires to the ACR probably do not need to be fused.   (the ground wire IS
fused, protecting against failure of the device itself.).  

Has anyone got any experience with this that would tell me otherwise?
Thanks!

Dave Syer   33-2
___

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Re: Stus-List Practical installation of ACR/VSR

[Dave via CnC-List]

Lol... Agreed Steve but in this case i tend to think of it as the lawyer state 
rather than nanny state.  (WAs so boggled by this sort of thing at one point 
that I put a label on my 6" bench vise that says 'caution - do not eat'. ). 
I don't think fusing the main house bank cable is such a terrible idea, ( over 
the years I have been occasionally startled by big sparks when wrenching, 
troubleshooting or using a steel fish tape - and not always carelessly) to your 
point though, marinas are not exactly plagued by unfused boats spontaneously 
combusting...

Dave




Message: 8
Date: Sun, 10 Jul 2016 09:30:17 -0400
From: "S Thomas" <sthom...@bellnet.ca>
To: <cnc-list@cnc-list.com>
Subject: Re: Stus-List Practical installation of ACR/VSR
Message-ID: <5DFB0BC1ADCB424C8002E769FBC91562@mordor>
Content-Type: text/plain; charset="iso-8859-1"

The nanny state invading our sailboats. 
"...connections of less than 7 inches..."  Really?

I don't see the need for fuses in the cables between the batteries and the 
selector switch. There is a difference between careful and paranoid. 

The U.S. coast guard inspected a friend of mine's sailboat, and among other 
things, told him that he was required to have nylon lock nuts on his lead 
battery post connectors. 

Good grief. 

Steve Thomas
Sent from my iPhone___

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Re: Stus-List Practical installation of ACR/VSR

[Tim Goodyear via CnC-List]

Steve,

I won't defend the standards (and they are not state regulated, but industry 
adopted ), but they do need some understanding.  The requirement is that all 
wire in a circuit needs appropriate overcurrent protection, not that every wire 
needs its own fuse.  

Following that, if all the wire in your battery to switch panel or battery to 
starter circuit is the same size then why not put your fuse at the battery 
rather than after the switch?  Its still only one fuse, but it's protecting 
more.  My batteries (it's a large bank) would deliver 20,000 amps in a short 
circuit condition, which is pretty much enough to weld with, so I have a 
class-T fuse as close as I can put it to the battery.

The US Coast Guard may have been proposing hex nuts rather than wing nuts, 
which have a tendency to loosen easily, but if it was the CG Auxiliary, all 
bets are off...

> On Jul 10, 2016, at 9:30 AM, S Thomas via CnC-List <cnc-list@cnc-list.com> 
> wrote:
> 
> The nanny state invading our sailboats. 
> "...connections of less than 7 inches..."  Really?
>  
> I don't see the need for fuses in the cables between the batteries and the 
> selector switch. There is a difference between careful and paranoid.
> 
> The U.S. coast guard inspected a friend of mine's sailboat, and among other 
> things, told him that he was required to have nylon lock nuts on his lead 
> battery post connectors. 
> 
> Good grief. 
> 
> Steve Thomas
> C MKIII
> Port Stanley, ON
> 
> - Original Message -
> From: "Tim Goodyear via CnC-List" <cnc-list@cnc-list.com>
> To: <cnc-list@cnc-list.com>
> Cc: "Tim Goodyear" <timg...@gmail.com>; "syerd...@gmail.com" 
> <syerd...@gmail.com>
> Sent: Sunday, July 10, 2016 08:42
> Subject: Re: Stus-List Practical installation of ACR/VSR
> 
> > Hi Dave,
>  
> 
> > 
> > Under ABYC standards, connections of less than 7" do not need to be fuses, 
> > neither do engine cranking circuits, but if you don't fuse other circuits 
> > you are asking for insurance / survey trouble if things go wrong...  Blue 
> > Sea have a great on-battery fuse (MRBF) that you could mount directly on 
> > the studs of the ACR without a lot of effort (and now required for your 
> > house bank).  You are protecting the wires, not the devices with these 
> > fuses, preventing short circuit current from causing them to ignite, so if 
> > the ACR wires are a different size than the battery cables you need 
> > different fuses.
> > 
> > https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A
> > 
> > I hope that helps!
> > 
> > Tim
> > 
> > Tim Goodyear
> > Ex-35-3
> > 
> ___
> 
> This list is supported by the generous donations of our members. If you like 
> what we do, please help us pay for our costs by donating. All Contributions 
> are greatly appreciated!
___

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what we do, please help us pay for our costs by donating. All Contributions are 
greatly appreciated!

Re: Stus-List Practical installation of ACR/VSR

[Dave via CnC-List]

Thanks For the thorough reply Tim, valuable and extensive detail there, and 
some food for thought.  I do understand the operation of the acr and the 
goals/theory of overcurrent protection, as well as voltage drop/cable ampacity 
more than my already-too-long post might infer. 
 Thanks for the -qualified - validation of the approach.Did not know the 
abyc 7" rule, nor that fusing the house bank is now 'code'.  (Amazing that it 
wasn't...).   I will review the abyc standards on this whole area, and also 
measure the battery to destination drop in the existing system.  This will tell 
me the margin in which my question exists.   Regardless, Am going to rethink, 
incorporate, and document standards-compliant circuit protection as well, to 
your point, this only makes sense.   Since this means recabling the house bank 
I will oversize the cable anyway, assuring that he extra few feet of cable are 
immaterial, drop-wise.A slippery slope as usual but a good one.
great stuff, very helpful,  and thanks again for taking the time.

Dave.

Sent from my iPhone

> On Jul 10, 2016, at 8:42 AM, Tim Goodyear  wrote:
> 
> Hi Dave,
> 
> Your ACR doesn't function as you describe; it is just a relay, with no 
> charging intelligence built in except that it will only close when it senses 
> charging (a voltage above a certain level for a certain time) on one or both 
> battery banks.  That shouldn't matter too much if both banks are the same 
> battery chemistry and the same age, but they will both "see" the same voltage 
> (minus wiring voltage drops) when the relay is closed, so make sure it's 
> appropriate.
> 
> You are heading in the right direction on voltage drops and overcurrent 
> protection (fuses), but voltage is crucial to battery charging and you don't 
> want to lose your boat to an electrical fire for the sake of a couple of 
> fuses...
> 
> Voltage drop will depend on current (how big is your alternator / battery 
> charger), wire length (total of positive and negative lengths) and wire size 
> - if it's going to be longer than recommended, increase the size of the wire. 
>  Blue Sea Systems probably have a calculator on their site or you can search 
> for ABYC voltage drop tables.
> 
> Under ABYC standards, connections of less than 7" do not need to be fuses, 
> neither do engine cranking circuits, but if you don't fuse other circuits you 
> are asking for insurance / survey trouble if things go wrong...  Blue Sea 
> have a great on-battery fuse (MRBF) that you could mount directly on the 
> studs of the ACR without a lot of effort (and now required for your house 
> bank).  You are protecting the wires, not the devices with these fuses, 
> preventing short circuit current from causing them to ignite, so if the ACR 
> wires are a different size than the battery cables you need different fuses.
> 
> https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A
> 
> I hope that helps!
> 
> Tim
> 
> Tim Goodyear
> Ex-35-3
> 
>> On Jul 10, 2016, at 8:17 AM, Syerdave--- via CnC-List 
>>  wrote:
>> 
>> Hello all,
>> Wondering about the practical vs the theoretical here.  
>> Am upgrading the DC system, adding a Group 24 dedicated start battery, and 
>> connecting the two group 31 in parallel to double the capacity of what will 
>> become the dedicated house bank.   Am adding a blue sea switch and ACR.
>> FYI - an ACR is a device that upon starting the engine essentially 'chooses' 
>> to top up the start battery fully before allowing the the house bank to be 
>> charged.   
>> Anyway, the manual states that the acr should be connected as close as 
>> possible to the battery (to prevent voltage drop from compromising its 
>> function to any degree) and both of its leads fused based on the wire gauge. 
>>   All makes sense, especially when the batteries are located At a distance 
>> from the switch or ACR.   however
>> The simplest installation is directly adjacent to the switch, not the 
>> battery.  The leads to the ACR would be very short and well protected - less 
>> than a foot.  (The battery cables themselves are not fused!)  In the 33-2, 
>> the distance to battery is still very short - less than eight feet of cable 
>> for sure.
>> 
>> In this situation, I can only see an infinitesimal difference in voltage 
>> drop by locating the ACR a few feet closer to the battery, really, no 
>> meaningful difference.  With a lead length measured in inches the positive 
>> wires to the ACR probably do not need to be fused.   (the ground wire IS 
>> fused, protecting against failure of the device itself.).  
>> 
>> Has anyone got any experience with this that would tell me otherwise?   
>> Thanks!
>> 
>> Dave Syer   33-2
>> ___
>> 
>> This list is supported by the generous donations of our members. If you like 
>> what we do, please help us pay for our costs by donating. All Contributions 
>> are greatly 

Re: Stus-List Practical installation of ACR/VSR

[S Thomas via CnC-List]

The nanny state invading our sailboats. 
"...connections of less than 7 inches..."  Really?

I don't see the need for fuses in the cables between the batteries and the 
selector switch. There is a difference between careful and paranoid. 

The U.S. coast guard inspected a friend of mine's sailboat, and among other 
things, told him that he was required to have nylon lock nuts on his lead 
battery post connectors. 

Good grief. 

Steve Thomas
C MKIII
Port Stanley, ON


- Original Message - 
From: "Tim Goodyear via CnC-List" <cnc-list@cnc-list.com>
To: <cnc-list@cnc-list.com>
Cc: "Tim Goodyear" <timg...@gmail.com>; "syerd...@gmail.com" 
<syerd...@gmail.com>
Sent: Sunday, July 10, 2016 08:42
Subject: Re: Stus-List Practical installation of ACR/VSR


> Hi Dave,


> 
> Under ABYC standards, connections of less than 7" do not need to be fuses, 
> neither do engine cranking circuits, but if you don't fuse other circuits you 
> are asking for insurance / survey trouble if things go wrong...  Blue Sea 
> have a great on-battery fuse (MRBF) that you could mount directly on the 
> studs of the ACR without a lot of effort (and now required for your house 
> bank).  You are protecting the wires, not the devices with these fuses, 
> preventing short circuit current from causing them to ignite, so if the ACR 
> wires are a different size than the battery cables you need different fuses.
> 
> https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A
> 
> I hope that helps!
> 
> Tim
> 
> Tim Goodyear
> Ex-35-3
> 
___

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what we do, please help us pay for our costs by donating. All Contributions are 
greatly appreciated!

Re: Stus-List Practical installation of ACR/VSR

[Tim Goodyear via CnC-List]

Hi Dave,

Your ACR doesn't function as you describe; it is just a relay, with no charging 
intelligence built in except that it will only close when it senses charging (a 
voltage above a certain level for a certain time) on one or both battery banks. 
 That shouldn't matter too much if both banks are the same battery chemistry 
and the same age, but they will both "see" the same voltage (minus wiring 
voltage drops) when the relay is closed, so make sure it's appropriate.

You are heading in the right direction on voltage drops and overcurrent 
protection (fuses), but voltage is crucial to battery charging and you don't 
want to lose your boat to an electrical fire for the sake of a couple of 
fuses...

Voltage drop will depend on current (how big is your alternator / battery 
charger), wire length (total of positive and negative lengths) and wire size - 
if it's going to be longer than recommended, increase the size of the wire.  
Blue Sea Systems probably have a calculator on their site or you can search for 
ABYC voltage drop tables.

Under ABYC standards, connections of less than 7" do not need to be fuses, 
neither do engine cranking circuits, but if you don't fuse other circuits you 
are asking for insurance / survey trouble if things go wrong...  Blue Sea have 
a great on-battery fuse (MRBF) that you could mount directly on the studs of 
the ACR without a lot of effort (and now required for your house bank).  You 
are protecting the wires, not the devices with these fuses, preventing short 
circuit current from causing them to ignite, so if the ACR wires are a 
different size than the battery cables you need different fuses.

https://www.bluesea.com/products/5191/MRBF_Terminal_Fuse_Block_-_30_to_300A

I hope that helps!

Tim

Tim Goodyear
Ex-35-3

> On Jul 10, 2016, at 8:17 AM, Syerdave--- via CnC-List  
> wrote:
> 
> Hello all,
> Wondering about the practical vs the theoretical here.  
> Am upgrading the DC system, adding a Group 24 dedicated start battery, and 
> connecting the two group 31 in parallel to double the capacity of what will 
> become the dedicated house bank.   Am adding a blue sea switch and ACR.
> FYI - an ACR is a device that upon starting the engine essentially 'chooses' 
> to top up the start battery fully before allowing the the house bank to be 
> charged.   
> Anyway, the manual states that the acr should be connected as close as 
> possible to the battery (to prevent voltage drop from compromising its 
> function to any degree) and both of its leads fused based on the wire gauge.  
>  All makes sense, especially when the batteries are located At a distance 
> from the switch or ACR.   however
> The simplest installation is directly adjacent to the switch, not the 
> battery.  The leads to the ACR would be very short and well protected - less 
> than a foot.  (The battery cables themselves are not fused!)  In the 33-2, 
> the distance to battery is still very short - less than eight feet of cable 
> for sure.
> 
> In this situation, I can only see an infinitesimal difference in voltage drop 
> by locating the ACR a few feet closer to the battery, really, no meaningful 
> difference.  With a lead length measured in inches the positive wires to the 
> ACR probably do not need to be fused.   (the ground wire IS fused, protecting 
> against failure of the device itself.).  
> 
> Has anyone got any experience with this that would tell me otherwise?   
> Thanks!
> 
> Dave Syer   33-2
> ___
> 
> This list is supported by the generous donations of our members. If you like 
> what we do, please help us pay for our costs by donating. All Contributions 
> are greatly appreciated!

___

This list is supported by the generous donations of our members. If you like 
what we do, please help us pay for our costs by donating. All Contributions are 
greatly appreciated!

Stus-List Practical installation of ACR/VSR

[Syerdave--- via CnC-List]

Hello all,
Wondering about the practical vs the theoretical here.  
Am upgrading the DC system, adding a Group 24 dedicated start battery, and 
connecting the two group 31 in parallel to double the capacity of what will 
become the dedicated house bank.   Am adding a blue sea switch and ACR.
FYI - an ACR is a device that upon starting the engine essentially 'chooses' to 
top up the start battery fully before allowing the the house bank to be 
charged.   
Anyway, the manual states that the acr should be connected as close as possible 
to the battery (to prevent voltage drop from compromising its function to any 
degree) and both of its leads fused based on the wire gauge.   All makes sense, 
especially when the batteries are located At a distance from the switch or ACR. 
  however
The simplest installation is directly adjacent to the switch, not the battery.  
The leads to the ACR would be very short and well protected - less than a foot. 
 (The battery cables themselves are not fused!)  In the 33-2, the distance to 
battery is still very short - less than eight feet of cable for sure.

In this situation, I can only see an infinitesimal difference in voltage drop 
by locating the ACR a few feet closer to the battery, really, no meaningful 
difference.  With a lead length measured in inches the positive wires to the 
ACR probably do not need to be fused.   (the ground wire IS fused, protecting 
against failure of the device itself.).  

Has anyone got any experience with this that would tell me otherwise?   Thanks!

Dave Syer   33-2
___

This list is supported by the generous donations of our members. If you like 
what we do, please help us pay for our costs by donating. All Contributions are 
greatly appreciated!