Reply
 
Thread Tools Search this Thread Display Modes
 
Old 08-31-2017, 06:51 PM   #61
Guru
 
dhays's Avatar
 
City: Gig Harbor
Country: United States
Vessel Name: Kinship
Vessel Model: North Pacific 43
Join Date: May 2015
Posts: 8,433
Quote:
Originally Posted by Seevee View Post
CMS and others......

Thanks MUCH for the info. Seems like the Blue Seas is a great unit, so here's the plan:
-----------
Replace the isolator with:
ML-ACR Automatic Charging Relay - 12V DC 500A 7620
-----OR------
SI-ACR Automatic Charging Relay - 12/24V DC 120A 7610

Is the ML-ACR overkill for this installation?
----------
Add a Magnum Energy 2812, 2000 amp inverter... or perhaps one slightly larger.
---------
Batteries currently in boat, 1 year old:
(4) 6v AGM 190 amp batteries, each in series for a 12v system, with two banks of two batteries each.
When they fail, replace with (4) Firefly Oasis G31 12v

=======

Does this make sense?
FWIW, I think that makes sense. I have the same inverter/charger and it has performed well. I have used the ML-ARC on my boat and it performed well and having the manual switch there was convenient at times. The ACR really is bullet-proof.
__________________
Advertisement

__________________
Regards,

Dave
SPOT page
dhays is offline   Reply With Quote
Old 09-01-2017, 02:03 AM   #62
Guru
 
Seevee's Avatar
 
City: st pete
Country: usa
Vessel Model: 400 Mainship
Join Date: Sep 2016
Posts: 2,211
Quote:
Originally Posted by Rossland View Post
Yes, this makes good sense, and is the setup on my boat. The ML-ACR is overkill only if you have small alternator. The Magnum inverter/charger is very good, but expensive. Something you might consider is keeping your old inverter as a backup. But make sure you wire the two inverters with an either/or switch since you can't have both inverters connected at the same time. ACR's, like any device, (including manual switches) can fail. Booster cables make a good backup.
Thanks for the comments, Rossland,
My alternator is an 80amp, I guess that would classify as not particularly big.
And, I currently have no inverter, so that would be new.
__________________

__________________
Seevee
Seevee is offline   Reply With Quote
Old 09-05-2017, 07:26 AM   #63
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 2,185
I have been starting my 392 v-8 big blocks with the typical combiner relay for about a year now with no troubles.
I have it wired thru a manual switch and it is powered when ignition to starboard motor is on. So if I turn ignition on, I hear it click on.
It is rated at 150 amp temporary use, and 90 amp continuous use.

I have a dedicated start battery, the combiner connects start bank to house bank. So if house bank is run down, at engine starting, house bank is not contributing anything to the start bank, so insignificant current flows, so no problem then.

If start bank is depleted, then house bank if it is not depleted, will contribute starting current. But, the wire gauge of #4 that is on the relay is going to limit current flow, it just can not flow hundred of amps. it might flow 150 amps.
Current flow will heat up the wire, but it is not going to just melt. A depleted start bank is going to suck current out of the house bank too, AND contribute some current flow to the starter even if depleted.

The combiner relay is connected to the battery positive of both banks, so I can't isolate the start bank from the relay combiner circuit by turning its switch off. So it will always be joining both banks together, which limits the current flow in a second way.

I have not yet had any problems with it.
I think like this, have you ever examined battery jumper cables?? They are mostly thin #8 or #6 gauge wire. They work fine jump starting a car, and they are longer than my 4 foot of wire joining my banks thru that combiner relay.
Jumper cables can get warm if your doing a lot of cranking, I have never seen them melt and burn. My connection scheme is that the combiner relay on starting is acting like a jumper cable. It is just a booster cable.

PERHAPS cranking a diesel is different....How well do jumper cables work on diesels? I used to own 2 GM 350 diesels, (awful motors) and had sometimes used jumper cables and they worked ok.

My opinion is, having a dedicated start bank is better. Your almost always going to have a fresh undepleted battery for starting up. And I think the dedicated start bank works well with a typical cheap combiner relay. I use one battery to start both engines. It works well every time.

the starter banks only positive connection is
port alternator direct connection through a fuse.
AC charger output from a 3 bank AC charger.
combiner relay
positive terminal of starters
a 3 way battery switch so I could manually join banks or disconnect the starter battery.

I have 2 three way battery switches. I could join or disconnect or isolate either bank. So by moving switches manually could make the house be the starter bank etc...

Both engine alternators are directly on the positive wire, fused, and can not be disconnected by moving switches.
sdowney717 is offline   Reply With Quote
Old 09-05-2017, 08:44 AM   #64
TF Site Team
 
Bacchus's Avatar
 
City: Seneca Lake NY
Country: US
Vessel Name: Bacchus
Vessel Model: MS 34 HT Trawler
Join Date: Nov 2014
Posts: 2,995
Quote:
Originally Posted by sdowney717 View Post
I have been starting my 392 v-8 big blocks with the typical combiner relay for about a year now with no troubles.
I have it wired thru a manual switch and it is powered when ignition to starboard motor is on. So if I turn ignition on, I hear it click on.
It is rated at 150 amp temporary use, and 90 amp continuous use.

I have a dedicated start battery, the combiner connects start bank to house bank. So if house bank is run down, at engine starting, house bank is not contributing anything to the start bank, so insignificant current flows, so no problem then.

If start bank is depleted, then house bank if it is not depleted, will contribute starting current. But, the wire gauge of #4 that is on the relay is going to limit current flow, it just can not flow hundred of amps. it might flow 150 amps.
Current flow will heat up the wire, but it is not going to just melt. A depleted start bank is going to suck current out of the house bank too, AND contribute some current flow to the starter even if depleted.

The combiner relay is connected to the battery positive of both banks, so I can't isolate the start bank from the relay combiner circuit by turning its switch off. So it will always be joining both banks together, which limits the current flow in a second way.

I have not yet had any problems with it.
I think like this, have you ever examined battery jumper cables?? They are mostly thin #8 or #6 gauge wire. They work fine jump starting a car, and they are longer than my 4 foot of wire joining my banks thru that combiner relay.
Jumper cables can get warm if your doing a lot of cranking, I have never seen them melt and burn. My connection scheme is that the combiner relay on starting is acting like a jumper cable. It is just a booster cable.

PERHAPS cranking a diesel is different....How well do jumper cables work on diesels? I used to own 2 GM 350 diesels, (awful motors) and had sometimes used jumper cables and they worked ok.

My opinion is, having a dedicated start bank is better. Your almost always going to have a fresh undepleted battery for starting up. And I think the dedicated start bank works well with a typical cheap combiner relay. I use one battery to start both engines. It works well every time.

the starter banks only positive connection is
port alternator direct connection through a fuse.
AC charger output from a 3 bank AC charger.
combiner relay
positive terminal of starters
a 3 way battery switch so I could manually join banks or disconnect the starter battery.

I have 2 three way battery switches. I could join or disconnect or isolate either bank. So by moving switches manually could make the house be the starter bank etc...

Both engine alternators are directly on the positive wire, fused, and can not be disconnected by moving switches.
Don't know if there is a question in there but this sounds like a DIY "system".
IMHO. I'd have someone more qualified than I am review and comment on the set up.
Wire size is not a good way to limit current...thats what fuses are for.
I don't undestand why have a combiner if the + are tied together and can't be separated?
Lighter gauge jumper wires are infrequent emergency use single conducter in open air...not permanently installed in ER.
I have to wonder what insurance position would be if thete was a fire caused by installation not in compliance w ABYC.
Really not trying to be overly critical but would prefer you had this checked out to be safe.
I'd advise my closest friend do the same.
__________________
Don
2008 MS 34 HT Trawler
"Bacchus"
Bacchus is online now   Reply With Quote
Old 09-05-2017, 08:54 AM   #65
Guru
 
City: North Charleston, SC
Country: USA
Join Date: Sep 2010
Posts: 4,385
If you have two different banks of batteries (or single batteries) and one is depleted, if you connect them together to start the engine (or whatever), the charged battery will attempt to charge the depleted battery and you may end up with less current for engine starting than just by using the charged battery alone.

Jumper cables can be a smaller gauge than permanent wiring because they are in free air when being used, not bundled in an enclose space or conduit.

A relay capable of carrying several hundred amps for engine starting will be a seriously large (and pretty expensive) relay.

Simple is best.
rwidman is offline   Reply With Quote
Old 09-05-2017, 09:18 AM   #66
Scraping Paint
 
City: CT
Country: US
Join Date: Mar 2017
Posts: 963
But also completely standard on sailboats and used all the time.

Stinkpots running for hours every day usually staying close to shore power can get away with alt-only charging, so ignition-based relay is fine or even a manual switch.

Cruisers may live out on the hook for weeks at a time, only see shore power a few days per season, not use their propulsion engine much at all, and therefore use at least three different charge sources.

In that context nothing is simpler or more robust than a good ACR, as with the Blue Sea ML series.
john61ct is offline   Reply With Quote
Old 09-05-2017, 09:20 AM   #67
Guru
 
City: Seaford Va on Poquoson River, VA
Country: United States
Vessel Name: Old Glory
Vessel Model: 1970 Egg Harbor 37 extended salon model
Join Date: Jan 2016
Posts: 2,185
My combiner relay circuit, the way it is designed if it ever comes into play for starting is acting like a jumper cable, a booster is all it will ever do.

This is sort of interesting, so I ought to do the following as a test and see what happens!

IF I disconnected the start battery, removing the lug, then the combiner relay would be the only thing sending power to the starters, and my guess, it would be like trying to start your car with no battery and only using jumper cables, it can not physically supply enough current and it will not crank. Likely it would go click-click-click on the starter solenoid as the voltage drop would be extreme. Jumper cables will do that and they do not catch fire either.... The starter relay just drops out the circuit loading for the starter, so you wont have these huge currents flowing. In which case the size of the wire limits the current as it works with the starter motor relay that disconnects the circuit due to voltage drop cutting out the starter relay.
A 4 gauge wire is big enough not to burn up but small enough that it might drop the volts enough to disconnect the starter relay, I will test this soon. By it's nature it becomes a current limiter and wont be a problem.

When I got the boat, it had a typical old timey setup of 4 six volt batteries, each one connected respectively to an engine system with a single 3 way switch to join banks and no combiner relay. What was bad about it, I liked keeping the 3 way switch on both, and I was always running down the batteries when anchored, then no way to start up without running the gen to charge them up.

After thinking about it, decided it only needed one good start bank for both engine, so all the other batteries can be the house bank, and the house bank is never used for starting.
The 6 volt batteries all got old and failed and I needed to get new batteries, so changed to 12v batteries.
The combiner relay spreads the alternator loading from one to two alternators that helps a lot to charge the house bank. With no combiner relay, the port side engine alternator never does much work, it is a wasted resource. The starboard alternator gets a heavy workout and that also stresses the drive belt.

And I tell you this. I have Delco 12SI single wire internally regulated 80 amp output alternators.
I have twin ammeters. With both engines running, and combiner switch is off, the ammeter for port having starter bank might say 10 amps, the starboard ammeter for house might say 40 or 50 amps.

When I turn on the combiner relay, port alternator output jumps to 30 and starboard falls from 50 to 30amps, so IMO, it works great for me.
sdowney717 is offline   Reply With Quote
Old 09-05-2017, 09:25 AM   #68
CMS
Senior Member


 
City: Casco Bay
Country: USA
Join Date: Feb 2016
Posts: 226
Quote:
Originally Posted by FF View Post
If it is powered by the ACC terminal (as designed) none of these problems exist .
Sadly this rarely happens. Builders rarely install them correctly because they often just accept the standard engine panel from Yanmar, Cummins, Cat, Deer etc. that does not have an accessory terminal on the ignition switch.. They simply wire it to the ON/IGN position and send it out the door. Using the ACC position for a solenoid by boat builders or DIY's is about as common as builders or DIY's wiring & wiring properly the AFD feature of a battery switch, almost non-existent..

Using the ACC terminal still does not solve thrusters, inverters or other high demand loads pulling more current than is safe across the solenoid when the motor is running.

Also adding a switch with the ACC position, such as a CH 712, brings the cost and labor time up so the value proposition shrinks. I also would suggest using the 200A capable CH solenoid that use silver contacts as opposed to bare copper which again increase the solenoid cost a bit.

Solenoids can be installed safely, and with good design, but rarely are. Today with the advent of VSR's/Combiners/ACR's/Echo's DC to DC chargers etc., and a large percentage of cruising boats, both power and sail, using alternative energy, the choice to use an inexpensive solenoid is a pretty rare one even for most builders.

An alternative to the ignition ACC terminal for solenoid activation is to use a separate manual switch just to activate the solenoid or to use the oil pressure circuit for the the solenoids excite. You can also create other methods too, or replace your key-switch, but this usually removes the "value" proposition of the inexpensive solenoid approach.

On nearly every boat that I have set foot on using an inexpensive solenoid, for charge distribution, the solenoid is excited before starting occurs and is excited by a basic ON/OFF ignition switch. I have worked on some boats with a separate "parallel solenoid" switch but owners often forget to use it or forget to disable it when they hit the 300A - 400A bow thruster or when at anchor.

My most recent (June) was a lobsterman with a large John Deer. The builder wired a parallel solenoid to the ON position of the ON/OFF John Deer key switch in the John Deer factory panel.. Steve was replacing about two 85A Cole-Hersee solenoids per season. He also had no way to parallel banks if he killed one, which he had done twice when the solenoids died, another builder blunder.. He now has an SI-ACR and a manual emergency parallel / crossover switch. The whole rework cost him significantly less money, in time, materials and labor, than just one of the failures of his inexpensive solenoids cost him.


Quote:
Originally Posted by FF View Post
And eventually should it fail, a $20.00 unit is more likely to be found on board as a spare than a few hundred dollar item.
The Blue Sea 120SI ACR can be had for as little as $65.00. The more expensive ML-ACR, about $150.00 & is 500A continuous rated, is not really necessary in many applications.

The spares discussion begs the real question though of why you would carry either an inexpensive solenoid or an ACR as a spare if your system is wired properly, with manual control & isolation, to begin with?

Neither are absolutely necessary, in a properly wired cruising system, they just make automated charging easier and help to remove human error from the equation. The ACR makes charging automated even when you're not there for solar & wind though and can also open itself when high loads are used.. This is something which a key on, manually excited device, can't do.

Still, you can easily live without either in a properly wired cruising system. Many owners do, until they murder an expensive bank of batteries, become stranded or require a tow.

Both an inexpensive solenoid and an ACR should be redundant devices to simply automate charging. One automates it with any charge source and the other with only one source.

There are many other spares, a whole other discussion perhaps, that can be significantly more important, such as a back up alternator, alternator re-build kit, starter, starter solenoid, spare motor mount, spare reversing gear, prop, prop shaft, injection pump, injectors, fuel pump, turbo, oil-cooler HX, HX, fuel injectors, belts, water pump, raw water pump, impellers, strainer gaskets etc. etc....

Everyone of the above items I have seen damaged or fail at higher rates than a $65.00 Blue Sea ACR yet none of them are a redundant device, unless you have a twin screw. An ACR or an inexpensive solenoid would be redundant in a properly designed and executed cruising vessel DC system. Kind like carrying a spare tire for the spare tire...

Other than belts or impellers etc. very few boaters carry any of the above items as spares except for some very experienced world cruisers with many miles under their keels.

The items listed above, and more, would probably be considerably more important to carry on-board a voyaging world cruising boat well before a device that is already a redundant piece of gear such as an ACR or solenoid.
CMS is offline   Reply With Quote
Old 09-06-2017, 01:29 PM   #69
FF
Guru
 
FF's Avatar
 
Join Date: Oct 2007
Posts: 19,853
"Sadly this rarely happens. Builders rarely install them correctly because they often just accept the standard engine panel from Yanmar, Cummins, Cat, Deer etc. that does not have an accessory terminal on the ignition switch.."

A good pre delivery survey should find this error , and rotary switch field cut offs not properly wired .

That the boat sales men talk owners out of a survey of a new boat , is sad as the owner suffers the defects from day 1.

If boats were surveyed before delivery marine fuel tanks might exist and a chain locker would not require a boat rebuild.

Sadly most folks purchase a boat used , so have no choice when the boats assembler is shy of basic knowledge or has cheaped out on labor.
__________________

FF is offline   Reply With Quote
Reply

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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





All times are GMT -5. The time now is 07:52 PM.


Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2019, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2006 - 2012
×