Experience with Balmar Digital Duo ?

[tallyhorob]

Add a Battery - PN 7650 - Blue Sea Systems Blue Seas Switch and lots of good info on that page click around a bit lots of drawing and etc for you to look at

[Extemporaneous]

We're a little different but I'll tell you what I've done/am doing.

First I went the Digital Duo route.
The switching I used is as per the marked up attachment. What I wanted to do is be able to use either battery bank to start the engine while allowing me to either combine or isolate either of the banks along with being able to isolate the house loads if necessary. I could not find a switch that could do that and so had to go with 3 separate switches.
My house bank is 4 @ 215 Amp/hr AGM's and my starting battery is 1 @ 215 Amp/hr AGM. The 800 +- pounds of house batteries are in the bilge and my 1 starting battery is higher.

Sorry I can't add more.

Cheers and Good-luck,
Extemp.

Originally Posted by SvenG

I just started looking into the Echo Charge and Digital Duo Charge functionality.

Right now we have what are essentially two identical 200 Ah house banks wired through an off/1/all/2 battery selector switch. As far as I can tell (messy wiring to be traced and untangled) the switch controls both which battery bank is being charged (by the alternator) and which is being drained (by the house and the starter). I'm not sure how the shore power charger charges both with the switch in the off position, but it does and I'll worry about that later.

I want to take the two separate house banks and turn them into a single 400 Ah house bank (all batteries bought recently and are identical). Then I want to install a dedicated starter battery which is charged with the Echo Charger per the above discussion.

What I'm wondering about is how to use the off/1/all/2 battery switch in that case ? For the house I'd obviously want a switch so I can turn the house off. But for the starter I'd like to be able to use the off/1/all/2 option so if the starting battery suddenly dies I can start off the house bank.

So, will I need two switches ? One to just turn the house on and off, and the second to give the off/1/all/2 for just the starter ?

Thanks,



-Sven

[downunder]

Interesting option on batteries indicated by the electrician wiz who does the lightwave catamarans on the Gold Coast in Aust.

For a recent LW45 with genset and A/c he fitted a 800amp house bank (4x200ah AMP's) and 1 similar battery for the 3 engines. keeps all batteries on vessel the same.

Sort of a different application but simplifying battery system on board.

[btrayfors]

Sven,

Yes, you'll need another switch.

There are at least a couple of ways to wire it all up. Your situation sounds similar to mine: I've had a 2-bank house battery system wired thru a 1-2-BOTH-OFF switch for many years. The house banks are physically separated....not the best arrangement, but it's what I have room for.

I always run my house batteries as a single bank, with the switch in the BOTH position. The cables connecting my banks are large, and I think that's the key....depending on the distance they are separated. In no case would you want to use smaller than AWG 1/0 cable, though.

My start battery is wired thru it's own separate switch. So I have two switches...one for the house batteries and one for the start battery. In my case, the second switch is also a hefty 1-2-BOTH-OFF switch. Normally, I use the #1 position only, which connects the start battery to the starter circuit. However, the #2 position on this switch is wired to the COMMON lug on the house-battery switch, allowing me to easily select the house batteries for starting if needed. As it turns out, a couple of years ago I did need to use it when one morning at anchor my aged start battery decided it had had enough! Worked like a charm.

As for the charging arrangement, I have ALL my charging sources connected to the house batteries, and use a digital EchoCharge to maintain the start battery. This works flawlessly, with no intervention required on my part. On most boats, the 15A maximum capacity of the EchoCharge is more than enough; no need for the more powerful (30A) and expensive DuoCharge, unless you want the programming capability.

Conceptually and operationally, this is a good system. When you get on the boat, just switch on the house bank (in my case, use the BOTH position). Then, if later you wish to use the engine, just switch on the start battery (in my case, the #1 position). Turn these off when you leave the boat.

Be sure to put appropriate fusing on all circuits.

Bill

[SvenG]

Thanks Bill,

that confirms that what I have in mind would work.

One follow-up question, do you charge the house batteries as one bank or two ?



-Sven

[isobelk]

after frying a couple of battery isolators, I switched to the Digital-duo. It works great. It is also programable to the specific factory requirements of my start AGM.

It also only is energized when the ignition key is on, so there is no power drain at rest.I have a 1400AH house bank AGM and a single AGM grp 31 start battery. I have a link battery monitor.My charger is an IOTA and it also functions as a powersupply, so it remains on to provide any 12v loads that are used during the off-season.

One of the great things about AGM's, is they hold charge for a very long time. As I worry about the bank suffering from possible damage by being on a 24/7 float charge, I have taken to disconnecting/isolating the bank after it is fully charged at the end of the cruising season. I do this at the 1-2-both switch.

I visit the boat every 30 days at a minimum during the off-season, and check the bank voltage. Usually every 90 days or so I will turn on the shore charger and observe the results - always the same showing a fully charged bank - I will float for a few hours and isolate the bank again.So far so good.

[btrayfors]

Originally Posted by SvenG

Thanks Bill,

that confirms that what I have in mind would work.

One follow-up question, do you charge the house batteries as one bank or two ?

-Sven

Sven,

I always treat them as a single battery bank. Always combined, no matter the charging source: battery charger, alternator, onboard diesel generator (thru Victron inverter/charger), etc.

Ideally, it's good to take the positive cable off of one end of the combined battery bank, and the negative cable off the other end. However, many setups with a split house battery bank often run a ground cable from each bank. Yours may be set up this way, in which case you might consider eliminating one of the ground cables, i.e., running it to the second bank instead of to a common ground.

Bill

[Dockhead]

Sven, I went through this last year on my boat.

I've got 4x 110AH batteries under my bunk as the "domestic" bank, and another 4x 110AH under the saloon sole as the "service" bank. Separate start batteries for engine and genset with their own alternators.

The two main banks are charged through a diode splitter from a separate 110 amp * 24 volt alternator.

They are also charged by a 40 amp * 24 volt Newmar mains battery charger which has two separate outputs.

"Domestic" was wired just as that; "Service" was for windlass, winches, bowthruster.

I thought it madness to have half of my battery capacity devoted to short-term loads and thought to combine the two banks. But I was afraid that the heavy short-term loads might disturb the electronics. Besides that, the two banks are far away from each other physically -- a good twenty feet or more.

So I did this: I wrote to the manufacturers of the diode splitter and battery charger to ask if there would be any ill effects if I bridged the two banks. Both replied that there would be no problem.

So I installed a heavy battery cable between the two banks with a cutoff switch. The idea was that I would disconnect the link between the two banks when motoring or on shore power; and connect them when sailing or at anchor when I need all the capacity of both banks.

What happened in the event was that I soon left the link active all the time. The heavy loads have never disturbed the electronics. I now have plenty of battery capacity. All is good.

You might try the same thing.

[Dockhead]

By the way, concerning the engine start battery: On my boat, this is a completely separate 12v system (my house and service banks are 24v). For emergency starting in the unusual event that the engine start battery dies (unusual because that battery does nothing but start the engine -- there is nothing at all to run it down), I carry -- jumper cables! So I would isolate the domestic bank, take the positive cable off one of the batteries there, and simply connect it with jumper cables.

[DITB]

As I am servicing my alternators and charge controllers, I am considering options to keep the start batteries topped up.

What I have is

2 HP Yanmars (Sailing Catamaran)
- Each has 12V alternator to charge the start battery only, and 24V alternators to charge the house bank

House bank is 24V, while start batteries for engines and genset are all 12V (3 in total). All are Lifeline AGM batteries, although I exchanged the house batteries recently to Victron (went from 500Ah to 440Ah).

If the engines aren't running for a while, there is nothing to keep the start batteries topped up. I am not looking for a bulk charging solution, just a float for long term servicing - and to avoid the surprise of no starting, when engines are needed.

Looking at the Digital Duo Charge - would I require three units (almost 800 USD!), or can one unit charge two batteries (like genset and one engine start bat)?

I want something automatic - at the moment I use small automotive solar panels that keep them topped up. It works, but isn't elegant!

[Stu Jackson]

Originally Posted by SvenG

What I'm wondering about is how to use the off/1/all/2 battery switch in that case ? For the house I'd obviously want a switch so I can turn the house off. But for the starter I'd like to be able to use the off/1/all/2 option so if the starting battery suddenly dies I can start off the house bank.

So, will I need two switches ? One to just turn the house on and off, and the second to give the off/1/all/2 for just the starter ?

Thanks,



-Sven

Here's how:

Basic Battery Wiring Diagrams This is a very good basic primer for boat system wiring: Basic Battery Wiring Diagrams

This is another very good basic primer for boat system wiring: The 1-2-B Switch by Maine Sail (brings together a lot of what this subject is all about)
1/BOTH/2/OFF Switches Thoughts & Musings | SailboatOwners.com Forums

These come from here:

Electrical Systems 101 http://c34.org/bbs/index.php/topic,5977.0.html

[phantomracer]

have had the duo charge for a couple years now. Haven't touched the 1-2-b-n switch since. Starting battery has been kept up without a problem. One of the best things i have put on the boat!

[DITB]

Originally Posted by phantomracer

have had the duo charge for a couple years now. Haven't touched the 1-2-b-n switch since. Starting battery has been kept up without a problem. One of the best things i have put on the boat!

With two engines and a generator, each with their own start battery - would I need three Digital Duo charge units? I want to keep all three batteries independant, not connected in parallel.

[phantomracer]

Originally Posted by DITB

With two engines and a generator, each with their own start battery - would I need three Digital Duo charge units? I want to keep all three batteries independant, not connected in parallel.

Not a clue. I was barely able to get mine installed. LOL.

I'd give Balmar a call to see what they recommend. They are quite helpful! Maybe Main Sail would have a good suggestion as well.

[DITB]

Originally Posted by phantomracer

Not a clue. I was barely able to get mine installed. LOL.

I'd give Balmar a call to see what they recommend. They are quite helpful! Maybe Main Sail would have a good suggestion as well.

At around 260 USD a piece, it's a lot of dough for trickle charging three start batteries. Having said that, it would be nice with automatic top-up - and it should make those batteries last a lot longer (I use AGMs from LifeLine for all three start batteries)