My mistake

Dennis W. · Dec 14, 2008

Have you considered the Blue Sea dual circuit switches along with an Automatic Charging Relay. Isolates both banks, keeps starting and house draws separate to minimize spikes, and allows combining if necessary.

Stu Jackson · Dec 14, 2008

You're OK with what you've bought

IF, that's IF, you're planning on a good size house bank and a separate emergency reserve (start) bank, the echo charger is the right tool. The combiner is better for split banks. Your boat, your choice, I recommend a larger house bank. The EC will work with ANY charging source, shore, alternator, solar, wind, on and on.

I have some serious reservation about the dual circuit switch. You may choose to read this entire long thread from our earlier discussions over at the C34 website message board: http://c34.org/bbs/index.php/topic,4623.0.html The dual circuit switch gets discussed on the second page of the thread.

Be careful in caring for your batteries. Get them charged up properly regularly however you choose to do it, equalize them and take good care of them. Chronically undercharged batteries won't last very long.

Many have suggested to me that the "best" thing you can get is a battery monitor. I left that to last, but learned it really should be first, because how much that goes back in is usually half of what you may think it would be because of the acceptance of the house bank. So throw in a Link 10 or equivalent and you'll be better able to manage your system.

sailingdog · Dec 14, 2008

Stu-

One thing you say that is at least misleading in that thread, IMHO, is:

The dual circuit either separates the reserve and house banks or combines them. There is NO position on the new switch that allow JUST the start bank to provide power. So, if your house bank is dead flat (for whatever reason), putting the dual circuit switch in the combined position means your reserve bank is gonna bleed into the dead house bank.

The main reason for combining the batteries is to start the engine, which, once started, will charge both banks if setup properly. If your house bank is dead, why would you combine the batteries??? I can't see any situation where you'd want to use the starting bank to provide power to the house side without starting the engine and had dead house batteries.

Most starting banks are relatively small compared to the house bank, unless you've just got two equal banks—which is not an efficient use of battery power in most cases—and combining a relatively well charged house bank with a dead starting bank shouldn't make much of a difference, given the disparity in their sizes—and should allow you to start the engine in most conditions.

I have and use a Blue Sea Dual Circuit Plus switch, and think it makes far more sense than a 1/2/Both switch does. This is especially true if the DCP switch is combined with an echo charger or ACR-type battery combiner.

Stu Jackson · Dec 14, 2008

Like we said in the referenced link

it's a boat, so there are many different ways to do things. My point is that there is no way it makes sense, at least to me, to want to combine banks when one is dead, so what is the purpose of the dual circuit switch, if not for that, which a 1-2-B can do just as well. So, as you noted: "If your house bank is dead, why would you combine the batteries???"

That's just my point, so I agree with you, so what's so great about the dual circuit switch that a cheaper 1-2-B won't do? There should be no reason to combine a dead bank with a good one, so what does the dual circuit switch do? Just that. That's why I don't get it. I wouldn't want to combine a dead bank with a good one. Plus, the dual circuit won't let you connect the reserve bank to the house load. It appears from the literature from Blue Seas and the West Marine catalog blurb that it requires the alternator output to run through the switch (noted in the last "unintended consequences" of the linked thread), so you have only 2 switch positions: separate or combined.

Yes, we also made the point of how the system is wired. Preferred is alternator to house bank, saves a lot of confusion.

If the house bank is dead, you could use your emergency reserve bank to run house loads, like minimum lights or anything else, because there's no reason you can't based on the size of a usual reserve bank. Do the math: 60 ah bank, 30 ah available - bank should almost always be full - turn fridge off, 30 ah, means a whole evening or maybe even a day without a house bank and with good energy management. Sounds like a good "reserve" to me. You do NOT have to start your engine immediately.

Seems that the easiest thing to do is run the alternator output to the house bank, and either use a 1-2-B or separate switches for house and reserve, but for one of those many people use a paralleling switch, which is just what the 1-2-B switch is to begin with! But paralleling one dead and one good bank makes no sense. But the dual circuit switch simply won't let you connect the house loads to the reserve bank ONLY and it runs the alternator output through the switch.

But, everyone has a different approach, all I was pointing out was the way the dual circuit is designed,so people can make their own decisions with some information on choices that's not in the promotional material. The linked thread discussed and then summarized my reasons.

John Nantz · Dec 15, 2008

Battery combiner comment

For some reason there seems to be a lot of used battery combiners in the second hand chandleries. Don't know why but that's what I've noticed.

Years ago when they first came out I considered getting one after an experience I had with dead batteries. The boat only hand two group 24s and after running the anchor light all night come morning they couldn't start the engine. Oh, and this was a new boat at the time so I was learning.

That was 20 years ago and I've never been close to having a problem since. Okay, so I've got a group 27 start and four golf carts now, but hey, it works.

One thing that would help keep the battery plates free of sulfate is a good high-output alternator and 3 or 4 step regulator (mine is a 3 step). Something that'll crank out a bunch of amps. That'll go a long ways toward helping to keep the plates in good shape. For that matter, if one hooked up to shorepower, so would an inverter/charger, one that put out enough amps in the charge cycle. My Heart Freedom 10 puts out 50 amps so that helps too. For my batteries this works fine but if your banks are significantly smaller they, of course, wouldn't need as much punch. Golf carts, especially, are designed to be worked.

And speaking of working, this approach must work because I'm still on my second set of batteries in 14 years and they're still going strong.

With regard battery monitors, I really like the Link 20 (but a Link 10 would work just as good), picked it up on a good special. It's been really handy for monitoring voltage and A-hrs. I've also got some solar panels so the Link is a handy addition. Personally, I'd also recommend a Link over a combiner. Heck, it's a lot more fun to watch!

Maine Sail · Dec 15, 2008

bsmith said:
Here's the question. The echo charger is designed for use with the shore power, not the alternator. Guess I didn't research enough on that purchase. Now, I'm looking for in a battery combiner. Any recommendations on brands? Anything I should stay away from? They don't look very complex. Xantrex PathMaker costs about 130.00 vs. Yandina sold by Defender is about 60.00?

Bob,

Read the directions again. It is designed to work off of charging voltage from ANY charging source. Any charging source can be a 120V AC charger or an alternator. The Echo is not connected to line voltage but rather directly to the house bank and it senses charging voltages and follows the charging source up or down...

Don S/V ILLusion · Dec 15, 2008

Bob
You most definitely can use the echo-charger regardless of the charging source.

Regarding the battery decision, amp-hr rating and plate size are often mutually exclusive; that is, the US Battery may have thicker plates meaning it should theoretically have a longer lifespan than the other higher-rated battery. It's a compromise only you can decide based on limited space, coat and the uncertainty of which will actually last longer.

Stu Jackson · Dec 15, 2008

Back again

Bob,

1. No I haven't finished the article, but most of the concepts were in the link I referenced.

2. You are quite correct about your conclusions on the echo charger, and Maine Sail and I, and now Don, agree with you, that's what it does. It's a current limiting relay - think about that definition for a moment; as compared to a combiner, which is just a relay. It ONLY gets "energized" by the incoming CHARGING voltage to the batteries, so shorepower has absolutely NOTHING to do with it. Don't trust whoever told you that nonsense. Bingo, you can keep it.

3. Without an energy budget, no one knows if your bank sizing is "right" but all it means is if it's too small you end up charging more often. Too bad you're stuck with year old batteries and adding new. The largest house bank you can make is better. Having four batteries but splitting into [almost] parallel banks is something you know about. Have you considered keeping only one of the one year olds and buying three new for a bigger bank? (I know it's easy for me to spend your $$$

- sorry). Heck, if they're in good shape and only one year old, why not do 3 and 1? Others may chime in here about mixing batteries if this is too heretical. 280ah for a house bank is not bad even if you have a fridge, only 140 "usable" but should get you two days on the hook if you turn the fridge off at night. The echo charge will limit the current to the reserve bank, so as you describe it, you'll have both a smaller house bank and a bigger reserve bank which is counterintuitive to system sizing.

4. THEN, you'll find out what a wimp your OEM 55 A alternator really is, but you'll have a LINK to show you. Maine Sail and I have different thoughts on alternators, regulators and recharging times. I would be interested in your experiences. Your existing alternator will NOT be happy if you connect it to a smart 3 stage regulator (because it'll be burned up by the regulator trying to charge a depleted house bank, as noted in my earlier link, or earlier discussions on this subject).

5. You're not missing anything on the batteries. Bigger physically is NOT necessarily bigger electrically, heck they're the builders and they rate their products.

Sounds good, all the best, have at it, matey!

Stu Jackson · Dec 15, 2008

Your OEM Alternator won't work with an external regulator

because it will fry the OEM alternator. It will overload the alternator and burn it up because it's an automotive alternator not made for recharging deeply discharged deep cycle batteries. Do NOT use the MC-612 with your old alternator. You would have to also disable the internal regulator if you tried to do this, but don't, please. I may have sent you here before: http://www.c34.org/projects/projects-electrical-system-upgrade-2.html

Also see: http://c34.org/bbs/index.php/topic,4669.0.html

Your choices: 1) use your old alternator with your new battery system, keep the MC-612 for when you upgrade your alternator (least expensive is the one noted in this link, others are Leece Neville, Balmar is the most expensive); 2) buy a new alternator to use with the MC-612.

All the sensors would tell you is that your OEM alternator was overheating and would switch the MC-612 to 50% output automatically. See: http://c34.org/bbs/index.php/topic,4454.0.html

Either way you'll have the Link to measure your input to the banks. If you harbor hop, and get to use the shorepower charger you'll be OK, but you didn't say what shorepower charger you have. If it's old, it could be killing your batteries anyway. If you anchor out only, you'll end up, with the old OEM alternator, of never being able to charge your banks fully and kill your (both new & old) batteries. The link above discusses the steadily diminishing law of returns with alternator charging.

"Something to do with temperature differences and charging rate" Nonsense. There is no reason you can't have individual batteries in the same bank distributed throughout your boat. Just use the right wire sizes between the individual batteries. We do that.

If you use just (1) of the 65 ah as the reserve, buy two new ones and use the other 65 ah battery as part of your new house bank. That's what I suggested earlier in Item #3 of my last reply, and thinking that others would chime in and say "don't mix old and new batteries." We'll see how that goes.

Anything else, let us know.

Maine Sail · Dec 15, 2008

Stu,

My first attempt at external regulation, years ago, was a factory 50 amp Motorola and a regulator conversion plate. It worked fine but then again I never deeply discharged below 50% and had a rather small 230 ah bank. My next alt was a 90 amp Leece-Neville and it too worked. If you were trying to charge a 450ah bank I say go bigger on the alt but if you don't discharge below 50% and only have a 240ah bank it would probably continue to work for a while as mine did.

I'm sure some have fried a small alt with an external regulator but they also probably had a huge bank and or deeply discharged or completely discharged the bank.. If you are concerned about over heating the small alt just use a temp sensor with the external regulator.

Stu Jackson · Dec 15, 2008

I agree about the summertime slips

and we like to anchor out, too. But given your idea for the solar, you can now return the MC-612 and put that $$ to good use against your solar panel.

Our experience has been that the load on the alternator controlled by an external regulator is a bit, if not a lot, over half of the rated output of the alternator, based on the house bank acceptance rate; it's most likely true that the acceptance rate of a smaller house bank wuld reduce this somewhat. JVISS and I had a discussion about this a few months ago, and after disagreeing with him, I eventually learned and came to the conclusion that in many cases a bigger alternator actually is better because, as the "hot alternator" link discussed, running alternators for extended periods of time at high loads isn't good. As Maine Sail just said, the guts of the alternators aren't too much different, so why get into burning them up. Car alternators have almost NO load on them, they're just used to keep a car battery full after using a handful of amps when starting the car, just like a reserve battery on a boat. The acceptance rate of a good sized bank (300-400ah) seems to be about 50A when 50% discharged. I've seen this on our Link 2000 with our 100A shorepower charger (a Freedom 15 combined inverter/charger): it starts out at 75 A and rapidly drops to around 50 when our 360 AH bank is down 50%; so does the alternator (100 A Blue Circle runs at 50 A). When we had the OEM alternator (and we had a Spa Creek Auto Mac) we only got 25 A out of the alternator using the Auto Mac; when the Auto Mac was turned off, it was just like an internally regulated alternator, a standard tapering charge that barely did anything to charge the batteries.

So, you've got some thinking to do about how you want to set up your old alternator electrical charging system. Have a fun winter dealing with that one!:dance:

Oh, I still have the Auto Mac, wanna consider it? The reason we changed our alternator, BTW, was that it was getting up to be 20 years old - don't know how old yours is.

Taylor · Dec 15, 2008

Dual Circuit plus?

> so what's so great about the dual circuit switch that a cheaper 1-2-B won't do?

I agree 100% that if my starting bank is dead I don't want to combine, I want to switch the starter load to the house bank. But there is one thing that the dual curcuit switch gives you - it isolates the house load from the starting load - which means your GPS will not shut down when you start you engine. That is a very attractive feature for me.

I looks like the way that is done in the blue-seas product world iis to use two on off switches and a combiner switch, but if the engine battery is dead, turn off the engine switch, turn the house switch on and the combiner on and you have the house bank connected to both house and engine loads.

If I were talking with blue seas, I would be asking 'why is this have to be so confusing'.

Two 1-2-both switches would allow either battery to be connected to either load.

Stu Jackson · Dec 15, 2008

But

Taylor,

One 1-2-B switch does do it. Either or.

And the Blue Seas dual circuit switch also appears to require running the alternator output TO the switch, which I don't think makes a lotta sense. Here's why: older boats have #4 wiring between the switch and the house bank. That's woefully undersized for a larger alternator. So, unknowing sailors could swap out their switches but neglect to upgrade the wiring to the banks. Not fun.

That's another reason why I don't like 'em, and recommend running alternator output TO the house bank, and determining how YOU want to charge the reserve bank.

Soapbox time over. Out. (Please note I did NOT say "Over and Out" - it's one of those phrases that's like fingernails on a blackboard to me, but I hear it every weekend on Channel 16!:naughty

I'm not sure I understand your "turn combiner on" part, because even if the combiner is ON, the relay doesn't close until a charging source reaches 13-something volts. Nothing's connected otherwise. (Unless you're talking about another switch that does combine the two banks - you know, just like a simple 1-2-B switch does!

)

Dennis W. · Dec 15, 2008

The Point of the Dual Circuit

The use of the terms house bank, starting bank, and reserve bank help to confuse the discussion. The purpose of the dual circuit switch is to turn on two circuits with one simple action while keeping the house and starting (reserve) banks isolated from each other. To use the house bank to power the house and your electronics. The isolated starting (reserve) bank is only used for cranking the engine. This system is designed to be simple, one switch in one "on" position with no spikes to your electronics. All systems are a compromise in some fashion and you just need to do what works for you and your boat.

Bill Roosa · Dec 15, 2008

3-way vs combiners

The reason you would want to use a 3 way switch to connect all the battery banks is so you can charge them with the alternator. If this is the way you are selecting which bank is attached to the engine starter you are also selecting which bank is attached to the engine alternator. So after a deep discharge of the house bank, you switch to the starter bank to get the engine running and then switch back to the house for an hour or so to get them charged then switch to both to insure the starter and house batteries are charged. This prevents the fully charged starter battery from trying to "charge" the dead house bats and start the engine at the same time. Connecting a dead bank to a charged one can result in some pretty substantial currents flowing in the wires and could be a fire hazard!!!!

I find that the 3-way is the way to go for the following reasons:
I'm in control of the situation.
There are no charging voltage penalties (important in wind and solar charging).
They don't go bad without any indication leaving you with a dead battery.
They are cheaper.
The codes dictate that you need a switch in any case so why add complexity

The down side is that you have to turn the switch to the right setting and that requires some understanding of the circuit and the situation you are in or expecting.

So, if you want a bullet proof setup that takes manual setting get a 3-way.
If you want an automatic system that may leave you high and dry use the combiner.

You should familiarize yourself with how to bypass either circuit so you can get one or the other bank charged in an emergency.

Stu Jackson · Dec 15, 2008

Bill Roosa said:
The reason you would want to use a 3 way switch to connect all the battery banks is so you can charge them with the alternator. If this is the way you are selecting which bank is attached to the engine starter you are also selecting which bank is attached to the engine alternator.

Bill, I agree that this is what so many have done. In my links to Bob earlier, and in other discussions, I am a proponent of getting the alternator output off the danged switch and run to the house bank, which poses it's own issue of how to charge the reserve bank and gets into combiners, echo chargers, oil pressure switches or, dagnabbit, just another simple switch. We employ a combiner. Nice analysis on your part, thanks.

Added later: Bill, the part about the "you are selecting which bank is attached to the engine starter you are also selecting which bank is attached to the engine alternator." is not always necessarily true. Only if they're wired that way, as you note later that folks have to figure out what they have and what they might consider. If your alternator output goes to your switch and it's wired between the alternator and the starter, with one wire or two, then, yes, it'd happen. Not if the alternator output went to the house bank, since the only output left on the 1-2-B C post is the output of the bank - distribution panel and starter.

Dennis, perhaps I was confusing with those terms, but here they are again: I agree with Maine Sail that they shouldn't be called "start" banks anymore, just reserve or emergency banks. That's because we agree that the house bank is fine for starting and the reserve bank is just there as a backup. So, still only two banks: house and reserve. Hope this helps. One of the links above includes my wiring diagram and, ooops:naughty: I have to go back and update that and remove the word "start" from the diagram!

Once in the combine position the two banks are connected electrically, just what ya don't wanna do, which is what I find wrong about the switch.