Battery banks and charging (another q.)

Clearly, I do not have the same system the other current poster has.

I've got a start battery for each engine. Of course, each engine has an alternator and regulator. I've got a couple weird battery switches presumably associated with each engine; they're adjacent to the engine panels. They each have honkin'huge wires leading down to the respective batteries. I was told that they were intended to charge the house bank from either engine; seems specious to me.

I've got a house bank. I've got a genset w/o start battery. All batteries are sealed lead-acid. I've got a battery charger which received 110v from either the shore or genset. The charger is wired to feed all three battery banks. I've got a 110v system fed from its own shore feed and from the genset. I've got a second, added 110v system fed from its own shore feed and also from the genset. The second one runs only the air conditioners. The original 110v-12v panel has a battery switch reading the usual Off, 1, Both, 2.

I've done just a little grovelling in the crawl space, and nothing makes sense. If it made any sense, I'd ignore this system until it failed to do its duty, and fix something else. However, when the boat is plugged into the dock, as recently as Sunday morning, the battery charger would leave about a 14v reading on the 12v panel meter which can be switched from Bat 1, off, Bat 2. The gen set feeding the battery charger leaves only a 12v reading on either battery banks. When the engines are running, the reading gradually creeps up from wherever it started (12v or less), to about 14v on either bank.

The only reason I'm blathering on is that the Norcold refrigerator/freezer doesn't like anything less than 12v; it gradually lets the contents warm/thaw.

In the 'true confessions' department, I've not noticed any sort of obvious relationship between the engine's battery switches and the willingness of one or the other start batteries to start the engine. So, Sunday, I left 'em both 'Off' (duh?!) and by two hours later, at 3:30, having driven across the Bay, the battery meter read 10 volts in both banks. The engines would not restart and the fridge was warming. The genset started right up and I charged the bats and ran the fridge; charged for over an hour. By 8 AM yesterday, the batts still read 12v but the fridge was warming. Started the genset, charged the batts and ran the fridge for an hour. For the remainder of the day and through the night we monitored the fridge and ran the genset for an hour. The fridge would be warming in about 4 hours. So, why 20 hours, then every 5 hours? We drove down to Annapolis today, two hours run time, about 5 hours from arrival and the fridge is running.

So the questions: Do I not have three battery banks? Three wires lead out of the charger, one to each bank (the ground is daisy-chained(!). What are the battery switches at the engine panels actually doing? They're shown on some of the old Perkins manuals but no explanation given. Either engine will start with its battery switch at Off, 1, Both, 2, although the stbd engine likes 'Off' less well.

DHeckrotte said:

What are the battery switches at the engine panels actually doing? They're shown on some of the old Perkins manuals but no explanation given. Either engine will start with its battery switch at Off, 1, Both, 2, although the stbd engine likes 'Off' less well.

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There are a few ways the 1/2/Both switches can be wired. No way of knowing how yours are until you get back there and look.

Edit: The answer above really sucks, sorry. Did you start the engines with the switches in the Off position? It sounds as if the alternators are wired to the switches, and then the switches distribute the charging current to the batteries that are connected with the switches. I have no idea how the engine would start with them both in the off position.

In general, I have always been led to believe that the 1/2/Both switches should be used to determine which batteries are being used to supply power, not for directing where the charging current is going. However, I have no experience with twin engines so that may be entirely wrong in that application.

Sounds like the batteries don't charge from the alternator if the switch is off. And it sounds like the batteries may be bad if the voltage dropped that fast. If they are only starting batteries that is.

I want to break this down bit by bit because I'm a little confused:

I've got a house bank. Normal
I've got a genset w/o start battery. Normal
All batteries are sealed lead-acid. Normal
I've got a battery charger which received 110v from either the shore or genset. The charger is wired to feed all three battery banks. Normal
I've got a 110v system fed from its own shore feed and from the genset. I've got a second, added 110v system fed from its own shore feed and also from the genset. The second one runs only the air conditioners. Normal
The original 110v-12v panel has a battery switch reading the usual Off, 1, Both, 2. Normal

However, when the boat is plugged into the dock, as recently as Sunday morning, the battery charger would leave about a 14v reading on the 12v panel meter which can be switched from Bat 1, off, Bat 2. Normal
The gen set feeding the battery charger leaves only a 12v reading on either battery banks. Abnormal, What is capacity of charger? The voltage should start coming up as soon as the charger is energized by the generator output. Is the charger in fact energized when running on the generator alone?
When the engines are running, the reading gradually creeps up from wherever it started (12v or less), to about 14v on either bank. Normal

The only reason I'm blathering on is that the Norcold refrigerator/freezer doesn't like anything less than 12v; it gradually lets the contents warm/thaw. Abnormal Does the Norcold auto switch to AC when available? Is there a circuit breaker from the 120V panel for the fridge that is turned on?

So, Sunday, I left 'em both 'Off' (duh?!) and by two hours later, at 3:30, having driven across the Bay, the battery meter read 10 volts in both banks. Abnormal No way both starting batteries should drop to 10v in a couple hours. If true they are shot. Are there other battery switches to disconnect each engine from it's starting battery somewhere else? Follow the + cable from the starting battery to the starter.
The engines would not restart and the fridge was warming. Abnormal The fridge should be powered from the house battery. This tells me the house battery was also low. Did any battery switch position allow engine start?
The genset started right up. Normal Gens will start off a low house battery.
... and I charged the bats and ran the fridge; charged for over an hour.
By 8 AM yesterday, the batts still read 12v but the fridge was warming. Was this on the anchor or on dock power?
Started the genset, charged the batts and ran the fridge for an hour.
For the remainder of the day and through the night we monitored the fridge and ran the genset for an hour.
The fridge would be warming in about 4 hours. Do you mean it would start warming 4 hours after the generator was shutdown?
So, why 20 hours, then every 5 hours? You are not fully charging the batteries in only one hour.
We drove down to Annapolis today, two hours run time, about 5 hours from arrival and the fridge is running. What does this mean?

So the questions:
Do I not have three battery banks? Yes. Port starting, Starboard starting and House.
Three wires lead out of the charger, one to each bank (the ground is daisy-chained(!). Normal
What are the battery switches at the engine panels actually doing? Since you were able to start both engines with these switch OFF, my best guess is they select which engine charges the house bank by paralleling to the that engines start battery. You need to trace out which battery is connected to what in each position. For example Port switch #1 might be the Port Start battery and #2 is the Starboard; The Starboard switch #1 might be the Starboard start battery and #2 is the Port. All kinds of possible combinations. The real question is is what are the common terminals connected to? The previous owner will know.
They're shown on some of the old Perkins manuals but no explanation given. Those are not boat specific.
Either engine will start with its battery switch at Off, 1, Both, 2, although the stbd engine likes 'Off' less well. Abnormal. Something should disconnect the engines from the Start batteries.
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Too technical for me. But one thing, I don`t like sealed LAs for house deep cycle batts, to me that`s not "Normal".

BruceK said:

Too technical for me. But one thing, I don`t like sealed LAs for house deep cycle batts, to me that`s not "Normal".

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Sealed LA are not my first choice either, but in my boat all the original batteries were sealed LA batteries in 2010. By the time I bought the boat this spring, the engine start and thruster batteries had been replaced. The house batteries, Chinese made 200AH 8D sealed LAs, are still going strong after 6 years.

I found some sealed LA are actually openable.
Opened one that had failed too soon, IMO, and found water level exposed the plates.
That one a flat long plastic piece you pried up and screw in fills were underneath. Dated 2011, it developed a shorted cell.

So I opened another working one that was from 2012, and water was down but still above plates. Added distilled water and snapped cover back on. They had extra side tabs on that cover, I broke them off to make it easier to remove next time I open it, and I noticed the cell holes were a snapping tight fit into the cover. The cover was raised and looked to be a part of the top, but of course had a tight seam all the way round.

Consider, they had to add water when they made it.

For example I know this one also opens, I have this one or one like it, mine seems longer, and pried it open.
Made for a BMW, Cadillac, Saturn, etc... The entire long top section 12 inches by 3 inches comes off exposing the cell holes.
http://www.autozone.com/batteries-s...t-gold-battery/703595_929681_0/?checkfit=true

High Wire said:

However, when the boat is plugged into the dock, as recently as Sunday morning, the battery charger would leave about a 14v reading on the 12v panel meter which can be switched from Bat 1, off, Bat 2. Normal
The gen set feeding the battery charger leaves only a 12v reading on either battery banks. Abnormal, What is capacity of charger? The voltage should start coming up as soon as the charger is energized by the generator output. Is the charger in fact energized when running on the generator alone?
When the engines are running, the reading gradually creeps up from wherever it started (12v or less), to about 14v on either bank. Normal

The only reason I'm blathering on is that the Norcold refrigerator/freezer doesn't like anything less than 12v; it gradually lets the contents warm/thaw. Abnormal Does the Norcold auto switch to AC when available? Is there a circuit breaker from the 120V panel for the fridge that is turned on?

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Good break-down.

Possibly useful to concentrate on these. If you're not seeing max current (amps)/rising voltage at first when the genset is running and the converter is supposed to be charging...

Maybe the switch settings control whether output from the genset is going to the charger? Or whether output from the charger is going to the batteries?

Does the fridge have it's own separate DC and AC (i.e., both sources) breakers? Or in-line fuses somewhere? Some will auto-switch, but only when both AC and DC are already being made available...

-Chris

Before the generator is brought online to the charging circuit, there may be a "ship-off-shore (or shop) switch that should be set to "ship" and there should also be a breaker for the generator. If these are in proper positions for the generator to come online, something isn't right with the genny.

I suspect the batteries are coming to the end of their useful life. If you are not a do-it-yourselfer, you should probably bring an electrician on board to run through things with you, and then consider his suggestions. And...be his apprentice while he is working. Another option is to bring a capable colleague onboard who can give you some direction.

My boat was well setup at purchase. However the PO did not run through all the systems with me on and It took me quite a while to learn all the nuances of how all the charging circuits worked. For example, it was sometime before I understood that the "digital duo charge" charged the thruster bank, accomplished with a relay circuit that allows the batteries to be charged as 12 volt although the thruster is 24 volt.

Jim
Sent from my iPad using Trawler Forum

JDCAVE said:

Before the generator is brought online to the charging circuit, there may be a "ship-off-shore (or shop) switch that should be set to "ship" and there should also be a breaker for the generator. If these are in proper positions for the generator to come online, something isn't right with the genny.

Click to expand...

Good point about the ship/shorepower switch. I assumed OP meant other AC-powered stuff on board works when the genset is running, but... that'd be a basic step to check.

-Chris

Lots of information! Thanks! Been offline since my posting - no 'phone/internet signal in Tilghman Creek (Claiborne, MD). Good signal here at anchor outside of St Michaels.

Responding to High Wires' extensive responses:

I assume that the charger is energized when the genset is running; it's on a breaker on the original 110v panel and everything else on that panel works the same (properly) whether the panel is energized by 'shore' or 'gen'.

I don't know whether the Norcold is smart enough to switch itself from 12v to 110v and back. It's supplied with a breaker on the 12v and another on the 110v panels, so I assume it's not so smart. OTOH, the Norcold surely is newer than the boat.

Stbd starting batt is new, the others unknown (new boat to us).

I believe that the two batt switches associated with the two engines are there to start either engine from either start battery. Each switch is connected to a start battery; what I do not know is which pole of each switch is connected to its battery nor how the two switches are interconnected (and it's not an easy place to see (w/o opening the engine panels and even then...)!).

All talk of charging w/o engines is by means of the genset; we have not been on shore power since Sunday morning. Thus my comment about whether the charger has decided to pack it in; it presented 14+v to the batts on Sunday morning on shore power, but now presents 12+v when on the genset.

The only disconnect between any batts and the engines is the main, original batt switch on the original panel. I can only assume that that switches' Off, 1, Both, 2 positions are not talking about the same engine start batts that the engine's switches are talking about; if so then the two engine start batts would comprise one bank and the house bank the other. But, if the two engine start batts were connected to the same pole of that main switch then the two engine's battery switches would be doing nothing, except in the event that one of that 'engine bank' were dead. Interestingly, the main batt switch is inscribed "Stop engines before switching to Off position."

Genny puts out 110v, according to the panel's 110v meter.

Gaah! I've simply got to ferret out the wiring! That, too, is not so easy to do; I believe that all the original wiring on the boat is bundled.

Any useful PO is at least two POs back in time. My PO was Annapolis Yacht Sales who took the boat on trade (for a Beneteau daysailer(!)) from a PO who'd had the boat for 6 years and did essentially nothing, including maintenance, for or with it. He'd bought the boat in NC, brought it up the ICW with his wife, after which his wife never went aboard - so the story goes.

What happens if you put every switch on BOTH?

High Wire said:

What happens if you put every switch on BOTH?

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ditto!

Oh, this ain't as simple as I supposed in my last post.

In answer to the two who questioned what happens if I leave all battery selection switches on 'Both', that's what I do normally. And I'd failed to do that on the day that precipitated the first post.

In the not-as-simple department; there actually ARE connections to all three batteries from the battery switches adjacent to the engine panels. I still don't know how they're interconnected at under the helm position.

"However the PO did not run through all the systems with me on and It took me quite a while to learn all the nuances"

Every boat will eventually sold to new owners,

Create Da BOOk for passing it on to them now, when there is no rush.