Combiner or Isolator
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dhays
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I'm not the brightest bulb, but that makes no sense to me.
Psneed, I hear what you are saying. A simple combiner switch could cheaply and easily combine the house and start batteries whenever there is a charging source. All you have to do is remember to turn the switch.
Remembering is always an issue for me so I prefer an automated solution with backup should it fail. I think it comes down to what works best for the individual. However, if an automated solution is desired, I think it pays to select a simple and robust solution.
I've used and ACR for my start battery. Now I use an Echo-Charger. In both cases they are simple and reliable.
True, but you can get them with a built in charger, and I've been told that they can replace the isolator. Just wondering if this is true and how it would work. Doesn't make a lot of sense to me either, but this came from a rather experience boater that has a lot of electrical knowledge.
Lou_tribal
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psneeld
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I would like to know which inverters are set up to handle 2 separate banks that do not have some other connecting device.
Havent seen one yet but it sounds like if they do exist, I couldnt afford one.
Havent seen one yet but it sounds like if they do exist, I couldnt afford one.
Don't ask your buddy any more questions about electricity.
Just to clear things up, the term "battery combiner" and automatic charging relay" are descriptions of the same device, just from different manufacturers.
This is not something designed to connect two batteries together to start the engine, it is a device to connect them together for charging.
If you want a way to connect both batteries together for emergency engine starting, a standard battery on/off switch wired between the two would do. Or a jumper cable.
This is not something designed to connect two batteries together to start the engine, it is a device to connect them together for charging.
If you want a way to connect both batteries together for emergency engine starting, a standard battery on/off switch wired between the two would do. Or a jumper cable.
An inverter/charger may have the ability to charge two or more separate batteries or banks of batteries but that is not the same as an automatic charging relay. The ACR allows a single alternator (on the engine) to charge two separate banks of batteries when the engine is running but separates them when the engine is not running so running the stereo, refrigerator, microwave, etc. does not deplete the starting battery.
It would be best to filter out future electrical info that your friend feeds you...
An ACR works automatically and seamlessly in the background, with all charge sources including; wind, solar, hydro, hydrogen fuel cells, alternator and shore chargers, to charge the banks.
An inverter/charger requires 120V or 240V in order to charge batteries. Your alternator, solar wind etc. can not use the inverter to charge multiple banks.
By the sheer nature of the design, key on excite, starting current will pass across the solenoid.
Key On Solenoid:
*Key on closes solenoid (parallels battery banks)
*Batteries now in parallel (before motor is started)
*Starter engages with batteries still in parallel
*Starter loads both banks, in-rush can easily exceed 1200A on large diesels and 450A - 800A on small diesels & many bow thrusters can pull in excess of 300A.
*Cranking current passes through solenoid very often well in excess of the solenoids rating.
*Brown outs and voltage transients can occur with devices that are powered off the house bank because house is now in parallel with the start battery during starting.
*Works only when key is on or only with alternator charging
Blue Sea ACR:
*Key on has no effect on the ACR
*If resting voltage was still high enough for ACR to be in parallel the SI feature (start isolation feature) instantly opens the ACR (isolates banks for starting) when starter solenoid is activated.
*Start Isolation prevents starting current from passing through the ACR and from creating brown outs or voltage transients on house bank electronics.
*Thrusters and other high demand devices can also be wired to utilize the SI feature.
*Even if SI is not used a sudden voltage sag, thruster, starter, windlass, inverter etc. will open the relay so damaging amperage will not flow across it.
*Once the voltage of either bank has met the "parallel voltage criteria" both banks charge in parallel.
*Once voltage falls below "parallel voltage criteria" the ACR opens and unparallels the banks.
*The ACR works with all charge sources; solar, wind, hydro, fuel cell, alternator or battery chargers with no human intervention or key activation.
In an adequately wired & engineered cruising vessel DC system any Combiner/VSR/ACR, Echo Charger, Duo Charger or other DC to DC charger, such as the Sterling DC to DC battery to battery chargers, are a redundant charge directing or charge management device. There are many good ways to charge multiple banks. Parallel charging via an ACR or other combiner is only one of them.
A failure, no matter how rare, only means you now need to manually parallel the banks during charging. If a vessel can not manually manage charging & bank isolation then the system was not very well designed for cruising to begin with.
Sadly I see far too many boats built with only a key on solenoid with no other means of directing charge when or if they fail.
If one wants to use a key on solenoid it should be rated to handle the maximum loads on the vessel, with the key on, whether that load is a starter, bow thruster, alternator or alternators, inverter, windlass etc.. The system should also be wired so you can manually do what the solenoid does.
The early 100A Pathmakers, one of the early combiners, were rather unreliable because they used a cheap low current rated solenoid. They could easily be fixed by installing a Blue Sea 9012 or the actual Tyco version contactor/solenoid that was up to the task. Course the Blue Sea / Tyco contactor costs more than a Blue Sea ACR, which is a better designed piece of equipment than the Pathmaker was so most Pathmakers got replaced by an ACR.
If the relay and system design are not fit for the task there will eventually be problems.
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LarryM
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WesK
This Blue Sea ML-ACR Automatic Charging Relay is definitely designed to do Just that. The 30 sec. Cranking Rating is 1450A DC.
"The ML-ACR (Automatic Charging Relay) and ML-RBS (Remote Battery Switch), when paired, offer complete battery management of large battery banks with the push of a button. In addition to automatically sharing the charge from an engine’s alternator between the start and auxiliary battery, the ML-ACR control switch provides momentary battery combining to assist with starting in the event of a low engine battery. Multiple remote battery switches can be easily connected to the ML-ACR with the optional Paralleling Link Bus for a complete remote battery management Subsystem."
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Absolutely.. The ML-ACR is really a robust piece of gear but it also has the SI feature so that during normal starting the house bank and start bank remain isolated. With the ML, in an emergency, it can most definitely be used for parallel starting and this is part of the design..
These also work very well to give a boost from a house bank to a thruster bank during high demand use. By manually locking it in parallel, with the Contura switch, you can take advantage of the house bank capacity, alternator output and the thruster banks capacity to feed your huge thruster demand with out it becoming weak...
Once done using the thruster you simply toggle back to ACR mode and it charges both banks automatically from all charge sources available....
These also work very well to give a boost from a house bank to a thruster bank during high demand use. By manually locking it in parallel, with the Contura switch, you can take advantage of the house bank capacity, alternator output and the thruster banks capacity to feed your huge thruster demand with out it becoming weak...
Once done using the thruster you simply toggle back to ACR mode and it charges both banks automatically from all charge sources available....
diver dave
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Thats a nice system. If installed will prevent many problems.
FF
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Key On Solenoid:
*Key on closes solenoid (parallels battery banks)
*Batteries now in parallel (before motor is started)
*Starter engages with batteries still in parallel
*Starter loads both banks, in-rush can easily exceed 1200A on large diesels and 450A - 800A on small diesels & many bow thrusters can pull in excess of 300A.
*Cranking current passes through solenoid very often well in excess of the solenoids rating.
*Brown outs and voltage transients can occur with devices that are powered off the house bank because house is now in parallel with the start battery during starting.
*Works only when key is on or only with alternator charging"
*****
This list of problems only occurs if the merge solenoid is not properly powered.
If it is powered by the ignition terminal of the key switch , yes one can have all these problems.
If it is powered by the ACC terminal (as designed) none of these problems exist .
For charging a battset the solenoid (of the proper amperage rating) is hard to beat.
For emergency starting from the house to assist a dead start bank, the rotary switch is far cheaper to pass big amps (with the right switch) than using a solenoid rated for mega amps.
Simply seamlessly charging the house during normal cruising is a different requirement from an emergency procedure.
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.
*Key on closes solenoid (parallels battery banks)
*Batteries now in parallel (before motor is started)
*Starter engages with batteries still in parallel
*Starter loads both banks, in-rush can easily exceed 1200A on large diesels and 450A - 800A on small diesels & many bow thrusters can pull in excess of 300A.
*Cranking current passes through solenoid very often well in excess of the solenoids rating.
*Brown outs and voltage transients can occur with devices that are powered off the house bank because house is now in parallel with the start battery during starting.
*Works only when key is on or only with alternator charging"
*****
This list of problems only occurs if the merge solenoid is not properly powered.
If it is powered by the ignition terminal of the key switch , yes one can have all these problems.
If it is powered by the ACC terminal (as designed) none of these problems exist .
For charging a battset the solenoid (of the proper amperage rating) is hard to beat.
For emergency starting from the house to assist a dead start bank, the rotary switch is far cheaper to pass big amps (with the right switch) than using a solenoid rated for mega amps.
Simply seamlessly charging the house during normal cruising is a different requirement from an emergency procedure.
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.
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?
Ski in NC
Technical Guru
I kept it super simple. House bank hard wired to panel via breaker. Start batt and house batt go through a 1-2-both switch to engine and gennie. Batt switch is under galley sink right behind helm and directly over batts, so short cables and easy to reach.
To start, put switch to 2 (start batt). Start engine. Switch to both and now both charge. After stopping engine, switch back to 2. Start batt now has no load and house is doing house stuff.
If start batt is weak, put switch to both to parallel house and start.
When on shore power, put switch to both so they get equal charge, eventually.
Thruster batt tied to house batt via breaker and light gauge charge link. A relay opens the charge link when thruster is on, so no volt dip on house bank when thrusting.
Never any problem with electronics dropping out when starting engine or thrusting.
I've considered going with an ACR, but my system is so simple and switch so easy to get to, that I just don't see the need.
To start, put switch to 2 (start batt). Start engine. Switch to both and now both charge. After stopping engine, switch back to 2. Start batt now has no load and house is doing house stuff.
If start batt is weak, put switch to both to parallel house and start.
When on shore power, put switch to both so they get equal charge, eventually.
Thruster batt tied to house batt via breaker and light gauge charge link. A relay opens the charge link when thruster is on, so no volt dip on house bank when thrusting.
Never any problem with electronics dropping out when starting engine or thrusting.
I've considered going with an ACR, but my system is so simple and switch so easy to get to, that I just don't see the need.
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diver dave
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That's because YOU know what you are doing.
I'll never forget my nephews first trip to the Bahamas on some rich guys Sea Ray. After a day at DOCK, the batteries were so run down they couldn't start an engine.
After a ocean drift dive, I was left adrift/afloat due to a friend's mismanagement of the 1, 2, off, both switch, favoring the ability to keep beer cold and not leaving enough juice for a restart. The afternoon dive turned into a night surface drift, eventually calling for the USCG.
My system is simpler than yours. Turn the key and start the engine. Stop the engine when desired. The ACR takes care of everything.
psneeld
Guru
Until it doesnt and with many people's electrical skills...maybe being forced to understand basics is a better approach..... at least that is what I have learned in 30 years of instructing operators.
What I learned when I had a boat with a manual switch was that I would sometimes forget to change it. That's why I installed an ACR on it. Next boat had one from the factory but it eventually failed and I spent most of a cruise connecting a jumper between the batteries when underway and disconnecting it when stopped.
I replaced the original with a Blue Sea unit (which had the terminals in the opposite configuration and different sized studs). I did it twice; once as a temporary repair and then again as a permanent repair.
I replaced the original with a Blue Sea unit (which had the terminals in the opposite configuration and different sized studs). I did it twice; once as a temporary repair and then again as a permanent repair.
FF
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"I had a boat with a manual switch was that I would sometimes forget to change it."
The simple solution is a check list as used on both small and large aircraft.
The simple solution is a check list as used on both small and large aircraft.
I think the simple solution is to remove the chance of human error where possible.
Now in my case, the boat's manufacturer had already made that choice so even though replacing the original combiner was difficult because of the location and the need to rearrange the wires, converting to a manual switch would have been far more difficult what with moving and extending heavy cables and finding a place for the switch.
Rossland
Senior Member
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.
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