The ProMariner Flyback 3-20 that was in our boat was totally useless, the fan never shut off and it was really noisy plus it just could not handle even the 4D's let alone the 4 X 6 volts.

I got an IOTA DLS - 55 charger with the IQ4 module that makes it into a 3 stage unit. They are very highly regarded on other forums but they are NOT marine units. I don't care about that, I mounted it under the chart table, not in the bilge were the other one had been. I bought it off a guy who sells factory refurbs on eBay.

So far it is the best charger we've had. When I turn it on to charge the bank my amp meter goes right up to 55 amps, it holds bulk charge until the batteries reach 14.6 volts, then it goes into acceptance for 8 hours at 14.1 if I remember right then it goes into float at 13.6 volts. If the batteries don't get used in a week, it will go into an automatic bulk cycle for a brief period of time to get some battery activity going, IOTA calls it automatic equalization. If you're running loads and the charger is on it picks the load up automatically, no current shows as flowing in or out of the batteries. The IOTA fan only runs at full speed when the charger is at max bulk and that only lasts a brief period of time, about 10 minutes it seems so far. The fan also is temp controlled so it only runs at the minimal speed required, most of the time it's not even turning.

We had a ProMariner Protech 30 in our last boat which cost twice what the IOTA did and it was totally inscrutable. Never knew what the hell it was up to and it never held the batteries at the same voltage twice.

I was going to get an IOTA 75 amp unit but we might be buying a small Honda 1Kw genset and I wasn't sure the genset could handle that, it will handle the 55 though.

Another side benefit of mounting it under the chart table, there's only 3 feet of wire to the batteries vs the 7 or so that was there before. I put an 80 amp breaker on the output, it is a one bank charger so I just ran a cable to each bank positive side and then a single ground cable hooked to my common negative bus. Very happy with this unit. I think I paid $125 US for it. They sell for about $300 bucks up here and I'd pay that in an instant for it.

I just use one charger. I ran a single lead out of the positive terminal on the charger to an 80 amp Buss breaker then ran two lines from the breaker, one to the positive output terminal on each bank. I have a separate AGM starting battery that I installed in a holder in the locker under the aft cabin, it is charged off an Echo Charger. There is a combiner switch at the engine that lets me lock both house and start banks together, and there are disconnects for the starter and house banks, so I can isolate and/or start from any bank I need to.

The house bank still goes through the 1-2-Both switch and I just leave it on Both all the time. I only kept the 1-2-Both switch in the event that if one 6-volt battery goes bad I can take that bank out of the system. Once I get caught up on boat projects I am going to post a bunch of picture and schematics of what I did.

With your setup and using just 1 bank at a time, yes, you would want to be concerned about overcharging the bank you aren't using. You could accomplish what you want to do by wiring the charger through the 1-2-Both switch though I believe.

Steve, our experiences have left a lot to be desired from Charles equipment over the years. I'm not familiar with Reya. I've heard of Iota from Maine Sail who regards them highly. Buy a single bank charger and get a combiner and you're done. The more readily available chargers from Xantrex are reviewed here: [url]http://c34.org/bbs/index.php/topic,4352.0.html[/url]

OTOH, if you were using your boat and your old charger works, what makes you think it won't anymore? If your daily or per sail draw-down is the same before you plug back in, the charger could care less how big your bank is, since it only has to replace the same amount anyway. Think it through before you open you wallet again.

Wow Steve, that's getting way complicated (and expensive) for very small chargers. I clearly am biased, but the IOTA with the IQ4 module is the best unit I've ever had. If I were in your shoes I would buy a 55 amp unit with IQ4 and wire it through the 1-2-Both switch. You can direct the charge to whichever or both banks, it's cheaper than any one you've mentioned so far, better quality (IMHO), runs cool and makes no noise, will top up your banks in a reasonable time frame. Put it under the chart table, chargers need air flow.

As for a 20 amp charger, I sent an email to ProMariner about the 20 amp unit in our boat never turning off the fan. They said it was hopeless to try to charge 2 X 4Ds of 360 amps total with a 20 amp unit, way undersized. You are, as I am, now into 464 amps so a 20 amp unit is just not going to cut the mustard. Or maybe they just wanted to sell me another overpriced underpowered charger?

It's hard to find anybody with something bad to say about IOTA's units. IOTA Engineering is in Arizona, as far as I know they make their own stuff.
Here's a guy selling IOTA DLS55-IQ4 for $180. I don't know this site I'm just using it as an example of what you can get the IOTAs for.
[URL="http://iotaengineering.net/id10.htm"]http://www.solarseller.com/_iota_battery_chargers___battery_tender_batte...

Hmm, I have had a Xantrex 20 amp charger hooked up to my 4 GC batteries for years. No problem yet. If fully discharged, it does take overnight to bring them up, but it does not seem to stress the charger or the batteries.

Sure, to do it now, I would probably buy the 40 or 50 amp model, but don't worry about damaging a good charger. This is actually the first time I have ever heard about sizing a minimum charger for a bank. I have only heard about not sizing too large a charger for a bank.

Steve, I know you've put a lot into your new battery banks, but the complications you've encountered seem unusual. Dual equal house banks were the norm many years ago. You have the makings of a great huge house bank with your four golf carts. Why not make them a great single house bank, buy a cheap Sears start bank for your reserve bank and dedicate your shorepower charger to the house bank only? The reserve bank hardly ever needs to be recharged, and you can use your 1-2-B switch to parallel the banks when you're motoring to keep the reserve bank topped off. Single charger output, great house bank for your fridge (daysail 50 ah, overnight 100 ah is the "normal" loads we see), and you're done.

Maine Sail and I had a discussion over on co.com about these issues a while ago. Here's the link, the meat of the discussion starts at the bottom of page 1 and then on to page 2: [url]http://forums.catalina.sailboatowners.com/showthread.php?t=104505[/url]

Good luck.

[QUOTE=Steve Frost;5518] The down side is forgeting to switch to the house bank and runnig everything down. [/QUOTE]

Au contrare, my friend! If you read the link I provided, Maine Sail says it eloquently:

What could be simpler than putting your switch on #1, leaving it there all day, and turning it off when you're done?

The ONLY time you need to switch the 1-2-B switch is if your house bank dies.

And, of course, as I mentioned, using it to parallel your banks to top off the reserve bank when motoring or on shorepower. You don't need a combiner, or an echo charger or anything else, you already have the switch.

It really couldn't be simpler.

I've had many discussions over the years with folks who lug around a battery charger. Why not simply build in a relatively bulletproof system that has a reserve and be done with it?

Maine Sail and I have been discussing this for over ten years, and he and I have also recently agreed that the 1-2-B switch works just as well as a combiner (which is a non-current limiting relay, compared to an echo charger). All you have to do is wait until the bulk phase is over to avoid over charging your reserve bank.

You use your house bank for everything, including starting the engine. If you have sensitive electronics, we have a simple wiring diagram for you that adds a switch and still lets you use your 1-2-B and can parallel and isolate banks to your heart's desire. It "dedicates" the reserve bank to the starter to avoid voltage drops on the electronics. I haven't found the need for it, but Ken Juul (a contributor to this forum and a Past Commodore of our Association) did, so we worked that up for him and many others.

And the best thing you can also do, while I'm busy here spending YOUR $$ (!!:):)!!) is get a battery monitor, too. All you need do is check the voltage occasionally on the reserve bank. I've been doing this for 11 years now.

I think your concept about drawing down your house bank before you sailed has great merit. That's where that battery monitor would have come in handy, because we advise most people to get that first. Of course, I didn't, so who am I to say???!!!:)

[QUOTE=stu jackson c34;5521]

Maine Sail and I have been discussing this for over ten years, and he and I have also recently agreed that the 1-2-B switch works just as well as a combiner (which is a non-current limiting relay, compared to an echo charger). [B]All you have to do is wait until the bulk phase is over to avoid over charging your reserve bank.[/B]

[/QUOTE]

How would you over charge your reserve bank by combining??

[QUOTE=Steve Frost;5513]Bud,

You are telling a compeling story, the price for this well respected unit is hard to ignore. My concern about a single output unit was that if I drew one bank down on a daysail, running the reefer all day will take its toll, if I run the charger through the battery select switch, I can direct the charge to the low bank and not overcharge the high bank. The down side if I do not get back to the boat for a couple weeks the high bank is not being maintained.

After giving you idea of wiring the Iota through the select switch it occurs to me that all I would need to do is to install to switches on the output of my existing charger attached directly to the two battery banks, I could then direct the Iota to charge the low bank and switch the Guest 2610 to maintain the high bank. If all batteries are topped I could let either charger maintain the batteries in the float mode. Having the extra umph from the Iota sounds great, I also like the idea of it being a good power supply for onboard tasks when hooked to shore power, my existing charger does not give clean DC and creates noise on the stereo. Campared to the other chargers I have looked at Iota looks to be a great value, and I have not seen any bad reveiws of this product.

Thanks for the input Bud.[/QUOTE]

Why not just add a battery combiner like the Blue Seas ACR. You then only need a single output charger which will charge both banks via the ACR relay without having to fiddle with the 1/2/BOTH/OFF switch. These relays can be bought for about $65.00..

I have one of the first Yandina combiners (they invented them) and it is still works fine.

The Iota's are great chargers..

The black box is wired to combine the reserve bank, the fuse on the right, and the house bank, the fuse on the far left. Simple three wire hook up ground, house bank jumper and start bank jumper. Connect all charging sources to the house bank and the combiner automatically charges the reserve bank.
[IMG]http://www.pbase.com/mainecruising/image/124590921.jpg[/IMG]

Echo Chargers and the Balmar Duo Charger are other options but significantly more expensive.

[QUOTE=Maine Sail;5523]How would you over charge your reserve bank by combining??[/QUOTE]

Yeah, one shouldn't. Just over-responding to Steve's concern about overcharging. The battery acceptance would limit input. But some of our members have reported overcharging their small reserve banks when motoring for long periods of time. I also have a shutoff switch on the ground from my combiner to turn that off even when 1-2-B is on 1.

[QUOTE=stu jackson c34;5527]Yeah, one wouldn't. Just over-responding to Steve's concern about overcharging. The battery acceptance would limit input.[/QUOTE]

Stu,

Just for reference I find this short response from Yandina extremely educational.

Rather than type a long explanation I will just copy a post by the owner of Yandina who actually invented the combiner concept back in 1994.

"[B] From Yandina:[/B]

[B]QUESTION: [/B]

If a battery is weak and not taking much of a charge then isn't there a chance the good battery will eventually be boiled dry or at least potentially or is there a safe guard for that built into the unit? Dose it sense the internal resistances? I would like to purchase several of these but need these concerns addressed.

Cheers,
Peter

--------------------------------------------------------
[B]ANSWER:[/B]

Peter this is an old and very common misconception of how charging works.

Think about it for a moment. You said "Isn't there a chance the good battery will eventually be boiled dry or at least - - "

The only thing that boils a battery dry is overcharging. Batteries start to overcharge and "boil" when the charging voltage gets to 14.2 volts and above. So if the voltage is above 14.2 you are starting this overcharge process. But the voltage is coming from the charger and the charger will stop charging at 14.2 and drop back to a maintenance voltage of about 13.6.

So if one of the batteries was to overcharge its voltage would have to be above 14.2. If the voltage on one is above 14.2 then the voltage on the other is above 14.2 since they are joined together. If the voltage on both is above 14.2 then the charger is faulty.

A Combiner can't make the voltage on one battery get higher than the other, it can only make them equal.

Read this article. [URL="http://www.google.com/url?sa=D&q=http://www.yandina.com/combInfo.htm%23Q..."]http://www.google.com/url?sa=D&q=http://www.yandina.com/combInfo.htm%23Q...

You need to stop thinking that a charger puts out current that has to go somewhere. A 20 amp charger rarely puts out 20 amps. All it does is put out voltage, the amount of current that flows is governed by ohms law. Current = voltage/resistance. In the analysis for each battery, the voltage is the voltage on its terminal coming from the charger minus its internal charge voltage. For example, say 14-13 or about 1 volt. The resistance depends on the size of the battery and its condition. So using a resistance of 0.1 ohms the current flowing into the battery is 1/0.1 = 10 amps. A smaller or damaged battery will have a higher internal resistance so the current it takes would be 1/0.5 = 2 amps. As its internal voltage rises, the voltage difference gets less, so if its charge is up to 13.5, current = 0.5/0.5 which is down to 1 amp.

A 20 amp charger doesn't force 20 amps into the batteries so that the unused current from one battery has to go to the other, it puts out a voltage and each battery takes what it needs depending on state of charge, overall size, overall condition etc.

We invented the Combiner in 1994 and have sold nearly 50,000 all on unconditional warranty. Numerous other manufacturers have made copies since then. If this was a problem we would have heard something by now. This has been a "bad" year for returns, we've had about 15. But of those 15, only 5 had anything wrong with them, some purely mechanical, one lightning. An annual failure rate of 0.0125% is why we can give unconditional warranty.

Regards,

Yandina"

There is a lot of misinformation about combiners/ACR's/VSR's and the overcharging issue is one that often comes up.

[I][COLOR="Blue"]A 20 amp charger doesn't force 20 amps into the batteries so that the unused current from one battery has to go to the other, it puts out a voltage and each battery takes what it needs depending on state of charge, overall size, overall condition etc.[/COLOR][/I]

Thanks, Maine Sail. That was a great description and should go a long way to helping folks understand more about battery charging. Our discussions about battery acceptance, included in the link I gave Steve earlier, are also helpful in understanding how the whole system works.

Steve, because we bought a Freedom combined inverter/charger in 1998, I was confronted with a basic question: how to charge two banks of batteries with one output. Most other boaters I knew bought simple chargers with multiple outputs, solved that problem for them.

I did a lot of research and found the combiner concept and used it successfully. This is what Maine Sail is explaining. You could use it for your split house banks or for your big huge house bank and your reserve bank. Either way, it works. As far as the 1-2-B switch doing it, too, think of it as a backup to the combiner.

Thanks, Peter. You beat me to the answer and certainly in much more detail than I was prepared to do.

This was discussed in great detail years ago on our Sailnet email list. It seems to be a very common misconception.

An ee on that forum told us in much detail that if a discharged and a charged battery are both combined or charged together, the amps all go to the battery which needs it.

Yes, the voltage at 14 or a little higher into a charged battery will cause a little water to be boiled away, but that is why we should check the fluid levels on a regular basis. No harm done. Your car alternator puts a near constant 13.6 or 13.8 volts into your car battery with no harm done.