dual purpose engine start/domestic batteries

[Whitelighter]

I need to replace some of the batteries on the boat.
Currently there are two banks of 6 12v 110Ah batteries. Port side are sealed units and I think these are designated just to start the port engine.
Starboard are very basic leisure batteries, which require topping up.

Previous owner set the battery chargers to over charge which resulted in one battery on the starboard side letting go fairly soectacularly, and the other 4 ran dry. I think the reason for setting over charge is the boat struggles/won't start of shore power.

No I am a Luddite when it comes to electrics.
I feel I should get engine start batteries for the port side and swap the good sealed units across to the starboard. The engines are Detroit 6V92 diesels - do they wmreally need 6 plus batteries up start? 1300Ah of batteries on board seems excessive yet I'm not getting the start performance

Thoughts?

 

[jac]

I need to replace some of the batteries on the boat.
Currently there are two banks of 6 12v 110Ah batteries. Port side are sealed units and I think these are designated just to start the port engine.
Starboard are very basic leisure batteries, which require topping up.

Previous owner set the battery chargers to over charge which resulted in one battery on the starboard side letting go fairly soectacularly, and the other 4 ran dry. I think the reason for setting over charge is the boat struggles/won't start of shore power.

No I am a Luddite when it comes to electrics.
I feel I should get engine start batteries for the port side and swap the good sealed units across to the starboard. The engines are Detroit 6V92 diesels - do they wmreally need 6 plus batteries up start? 1300Ah of batteries on board seems excessive yet I'm not getting the start performance

Thoughts?

Different measurements for differing things.

Ah measures the total capacity of the battery bank - that may be something drawn off slowly to power something such as lights.

Engines need a large amount of energy for a few seconds to turn them over and get them started. That is usually expressed in CCA - cold Cramping Amps. I'm not sure of your engines but a quick google search revealed minimum CCA rating of 950 to start each of your engines. Personally I would go larger - minimum of about 1200.

Ideally you would have 1 dedicated engine start battery for each engine then a totally separate domestic bank. For that, CCA is irrelevant - just put in as much AH as wallet , available space, electrical demand requires.

 

[CX54WEK]

You need to find out the recommended CCA for your engines and then get batteries to suit.

Could be that your current set up isn't rated properly.

If your port battery bank really does only start the engine it seems a bit excessive to have so many starting batteries!

 

[rafiki_]

On my Azi, the port side bats (2x115 Ah) are service, and the stbd side a is 1x220 Ah (engines) and 1x88 (gennie). While my engines are somewhat smaller than yours, 2x Cat 3126, I have never suffered from slugglish starting, even in the midst of a cold winter.
You have a lot of batteries on board, so do you have an inverter rather than a genie?
What level of voltage do you see when the batteries are off charge? Should be 12.5 to 13V. If dropping quickly to 11.5V (over a few days), then this would indicate battery failure. Never a good idea to overcharge, and I'm not sure how you would do this? On charge, the batteries should be seeing 13.5 to 14V. Should you have the right voltage, I would think you have heaps of power to start.
Shore power is not designed to start your engines, and is a red herring imho.

 

[Portofino]

"struggles /won't start off shore power "
That does not sound good .You mean you have to leave shore power on to crank em over ?
How does it work @ anchor ?

Ideally 2 banks
One dedicated for both engines only
T other domestic
On a helm a x over switch so you can opt to nick some Dom if staters are low

Charger -they decay over time ,ie do not just go out like a light .
We started to experiance odd times where 2nd engine needed the x over and I have various guages ( all unfamiliar )
Any how the boat leccy who fitted the A/c tested the charger. ,supposed to give out 40 amps was actually giving 3-4 max
So batts not really getting enough juice from shore power + charger
Alternators fine so a run followed by anchor -no symptoms at all and guages = fully charged.

So sounds like you need a new 2016 modern charger ,that will detect when they are full and automatically switch to float
Not blow em up .these days a modern charger can sence what to do and when to float -trickle charge /maintain
dolphin 80 is what I have now .
Gel bats too these came with the boat new summer 14 - 2x 180 aH -per bank -Dom + engine .
We had acid /wet ones on the S/skr and these needed topping up -guardiene -suposed to ck ? .
We keep shore power on + ( smart ) charger all the time @ marina -past 10y -no probs -
Engine cranking is more to do with Cold Cranking rating ,iam no expert but maybe ck out DD website for correct size batts .
But ck out your charger 1st and if it's an old one -replace with a smarter one

 

[Whitelighter]

I have very new chargers, that auto switch to float.

I suspect the batteries were the cheapest possible as were fitted shortly before sale (but before I viewed).

The shore power thing - the port engine will start off the batteries but not after a few hours at anchor. That said I haven't tried isolating the engine batteries on the hook.

I have a jump switch on the dash. I'm happy having a dedicated port start and jump to starboard. I'm not in the position to rewrite the boat - this is how Ferretti installed it and it's a significant job to rip it all out and re wire

Thanks for the CCA number. I can go and find batteries of that size.

Assuming can I link like batteries together - ie two big start batteries then for smaller CCA regular batteries?

Port side are gel batteries. Starboard are led acid

 

[pmagowan]

Is this a normal setup on motorboats? I would have thought engine starting would be even more of a priority than for us raggies! The basic system, which is easy to set up, has a start battery dedicated to the engine start and which charges preferentially to the house. I presume you simply have 2 of these if you have two engines. Each has to have the CCA required for your engine. A VSR can sense the voltage then, when you anchor up and are using domestic power from the house bank, it disconnects the start batteries and thus they stay fully charged. It is very easy to wire for this type of system and then you never have the risk of a flat start battery and the engines always have a good cranking battery available. The house bank is then as many AH as you like and can be emergency paralleled with the start batteries if needed for any reason.

 

[Otter]

That's a huuuuuge bank for starting, lorrys with bigger engines start with fewer! The first place I'd look to is the wiring from the batteries to the starter motor, is it thick enough? Is it clamped tight? Is it arranged so that neg comes from one end and pos from the other end of the bank or is it both leads off one battery? Is the cable corroded and what condition is the starter in? Sounds like the PO bodged another issue by just adding more batteries.

 

[boatingdave]

Too much emphasis being put on voltage measurements. Its good as a rough guide but thats all. Valid comments in the responses - the 'Ah' rating is the capacity rating, the CCA is the Cold Cranking Amperes rating (this is the one that determines the 'oomph' it can give you over a short time when you try and start an engine - this rating is quite important). The best thing you can do is to purchase/borrow a lead acid battery tester which will give you an accurate picture of the health of the battery(ies). As stated - the shore power has nothing whatsoever to do with the starting ability. All of the power should come from the batteries. In fact if the batteries are stuffed and you do try and start the engines off the battery charger that could cause you some significant wiring issues. Over charging will produce lots of Hydrogen (explosive) and will boil off the electrolyte if they are open vented. I have two 475HP engines and a 180Ah 1000CCA battery for each if that helps as a guide. A common configuration is one engine has a single battery which is dedicated to that engine and the other engine uses the bank that also serves as the supply to the rest of the boat. In this configuration you would always be able to get the engine (and/or gennie) running which should then kick in the charging circuit for you to be able to start the other engine or if the chargers are separated (i.e. no VSR's or similar) then you may have a switch to temporarily join up all the batter banks. It does sound as if you have duff batteries and as has been mentioned in the various threads you need to have a look at the set up. If I can help at all, send me a PM and I can find out a little bit more about what you are trying to do.

Edit - I was writing this in work and hadn't noticed some of the other responses coming in. Most of the questions have been answered. It does sound as if you need to do some work and ensure its set up properly which it isn't.

 

[boatingdave]

Oh and don't forget - any duff batteries in the bank will drag the others down too so they have to be separated before testing and if they have left the duff ones in and just added additional batteries it wouldn't have helped much as the duff battery will discharge the decent ones and reduce the CCA abilities.

 

[Portofino]

Do you have the Ferretti hand book ?
Although in Italian , (like my Itama ) - there are diagrams and numbers re batts .
The engine bats should start both .
Jump switch sounds like a x over ? Using some Dom to top up the once only depleted main engine batts ?

Hopefully it's just the batts can not hold enough or are being drained faster /cannot keep up with drainage ( fridges etc )
All the same charger out put need ck ing .i found out via leccy ( Italian btw) how to read various guages n the
Panal .We have a amp charge function -show how much juice s being put in ,when charger is on .
So we know how much of rhe 80 ah is being used -can see float too when they are full.
What instrumentation do you have ?
Presume V ,but anything else ?

 

[Whitelighter]

Hi P,

Yes have the full Ferretti book- as you guessed in Italian.
I'll post a pick of the guages/read outs I have on the panel, and the battery chargers.

Edit:

Here is the status of the currebt panel

The battery service and motor show 13.6v - if I turn the battery charger breaker off this drops to 13.2v - which suggests the chargers are doing something. The charger control panel is at 0 - it maybe when new charger were installed this readout was by passed.

Looking at the Ferretti manual it confirms 6x 12v 100Ah 820 A batteries for the motor and the same for services:

Though the book also shows three for port, three for starboard and 6 service. Which is what I would expect
This is not how Seralia is currently set up

 

[kashurst]

as per other posts on battery size, sounds like the batteries although of recent vintage, may have been allowed to go completely flat in the recent past. If this happens they generally don´t recover and do exactly what you are experiencing. I have never bothered about getting leisure batteries and starting batteries. On a power boat it doesn´t really matter much as you use the engines most days when on board or have a gennie. I have found out here in the med its hard enough getting the right size and terminal layout, so I just get what ever is available that fits. (and hopefully cheap)

might be worth taking off and cleaning with wire wool or emery cloth, all the big fat battery cable connections to the engines as well. It only takes one gungy connection to let the whole thing down.

 

[Whitelighter]

To give the full picture:

Chargers

And the port bank:

Starboard

The starboard bank have been left to go dry so I'm sure they are knackered. The question is what to replace them with.
The terminals have different wires going off at different points on top of the daisy chain wires.

 

[kashurst]

The starboard side look like standard lead acid batteries, probably just a local own brand which if looked after would be perfectly OK. The port side calcium batts I looked up.

I just googled calcium lead acid battery, they are basically just a lead acid type battery but the calcium component increases lifetime and shelf life. However they do not like being deep discharged and they suffer other problems.
I cut and paste this from CTEK website- Calcium Lead Acid Batteries; The other reason is inside the battery. The low water loss has been achieved by reducing the gassing through replacing the Antimony in the grid with Calcium. These so called Calcium/Calcium are great from most aspects. The water loss is reduced by more than 80%. The self discharge is reduced, which extends the shelf life in a store. Unfortunately they dislike being deep discharged.
The problem with Calcium/Calcium occurs when they are deep discharged. The reduced water loss on these batteries is gained by reducing the gassing during recharge. Unfortunately this gassing helps to mix the acid. As a result the Calcium/Calcium batteries very often experience stratification, i.e. uneven acid weight height wise. The acid weight could be 1.17 or lower at the top and 1.35 or higher in the bottom for a battery that seems fully charged. This could cause sulphation and grid corrosion, which leads to underused capacity and premature end-of-life.--

So I would just go for bog standard lead acid truck batteries for both banks of batteries,
because - they are usually cheaper, easier to get, with so many batteries on board you are unlikely to ever get close to running them flat in normal operation, in an emergency if they are all the same type you can swap them around and if something happens and they all go completely flat you won´t be quite so p@ssed off than if you bought expensive AGM etc batteries.

just check that your chargers are set up for your everyday lead acid type. (some chargers have adjustment/settings for glassmat/gell batteries etc but they can all usually do the bog standard type perfectly well). The tricky part will be finding the right physical dimensions, terminal orientation and the nut and bolt terminals you have. It is possible to get battery terminal adapters that clamp on the typical lead lump/column thing, and have a threaded stud and nut to put the cables on. If you go that route make sure you get +ve adapters and -ve adapters as they are slightly different sizes (guess how I know that!)

 

[Whitelighter]

The chargers have switches for cal/cal wet gel and one other. Both currently set to wet.

 

[Portofino]

13.2 v is fully charged -that's what the manual says and that what you say the 13.6 V drops to ,after the charger is off .
13.6 is the correct output ( mines @24 v -but reads 2x @ 27.2 and drops to 26.4 when the C is off )
So -ok there .
One thing puzzles me - two chargers with each two out puts .
Generally -- Chargers can come with a few out puts .so one Charger via its seperate out puts can connect to Port ( engine ) stb Dom -and any other Geny ?
They can have in this case 3 microprocessor s running / charging each output differently depending on what bank needs what ?
You have two out puts on each . Charger but , one set of LED,s -are the side ones same as on the face ?
This suggest ( happy to be corrected ) that both outputs are controlled by one microprocessor hence a set cooked wet batts ? Cos it's charging two set(s) up -but only have one "Dc control " - guage which is prob the domestic.
This accounts why you cannot tell the state of the engine batts and have to use the x-over or "pararell" switch on the dash
Can you turn each batt bank on /off so there is only one on at a time and see what the "Dc control" reads .
We need to find out state of engine batts ?
Well we know there duff cos you are using some Dom @ x-over switch for 2nd engine start

2nd charger -i am wondering if two chargers= one for each bat bank ? -but i think if it all works - you have 4 x 13.6 v going out -two each on the chargers
So maybe 1 for Geny bat and 1 for port engine bat and 1 for Stb engine bat and 1 for Dom batts ?

As some one said there's a duff batt or 2/3 in there somewhere ? And they are dragging rest down re CCA

 

[Portofino]

Is there a wiring diagrams in the manual ? Showing battori Motori and battori domestica ,battori Groupe ?
MapishM will flame me for carp IT

 

[Whitelighter]

All makes sense p.

I can isolate the engine and domestic batteries in the cockpit.
So I can turn the engine set off and see what the panel does.

I suppose the next thing is get a battery tester and identify which batteries are good and which need replacing?

There is a generator battery somewhere but I've yet to find it

 

[Whitelighter]

Is there a wiring diagrams in the manual ? Showing battori Motor and battori domestica ,battori Groupe ?
MapishM will flame me for carp IT

Yes, but they are contradictory.
Just by the pool but I'll post a pic when back on the boat.