Azimut 46 - new battery charger system plus service/house batteries, engines battery and gen. battery

[Skipper Felice]

Some experience and helpfull information - tips will be gratefully received.

On my boat - Azimut 46ft, year 2000, the last owner did not do god maintenance for the electrical system: I have to replace the whole battery and charger system.
The whole energy system should power the boat at anchor for 2-3 days. For offshore I can use the generator to recharge if needed.

Based on various information I will not go for lithium battery systems.

I plan to use VICTRON charger for shore connection (32A) / KOHLER gen. output 220V, 7kW. All management components from VICTRON.
Whole system is 12V.
I will need 3 x 220Ah service batteries. (+/- 650Ah total) (deep cycle?)
I will need a new engine starter battery, high current, +/- 200 Ah (for Caterpillar 3208 engine)
I will need a new generater starter battery, high current, +/- 100 Ah (for KOHLER 7kW)

What type, brand or supplier do you recomend for good, reliable batteries? What is your experience with different batteries on a motor boat 50ft?

 

[prinex]

I have marine lead batteries for engines and starter, for service gel (4x200ah), the type used for solar panel installations.

I need in average 14 Ah to keep fridges etc running, I converted all 40-odds lightbulbs to led (they where halogen before, 20w each...) so going down to 50% battery we have around 24 hours before the generator has to start again (longer if not so hot, if noone opens/close the fridges 20 times a day etc).

The battery charger is from Dolphin, it loads 60A x 24v or such max so that we need to run it 3 hours or so to get the batteries to 90% (after that the charger will start loading less and less so its a bit of a waste to let the genset running).

I thinking of installing an inverter so that we can charge phones/laptops or run a simple fan instead of aircon, maybe a project for this winter...

 

[Alicatt]

We have 24V for start and domestic, with some 12V instruments on the upper helm.

When we bought the boat, like yours, the batteries were done, charging them up triggered the gas alarm so we replaced them, the original ones were 2 VMF semi traction 230Ah in series for 24V they had no balancing of the charge between them and one battery took all the charge and left the other low, replaced them with a pair of Varta semi traction 260Ah with a Victron battery balancer to even out the charge and provide a bluetooth battery monitor. The Varta batteries will be in the boat for a year come Sept.

A friend with a 50' trawler yacht has just changed out his VMF batteries, which were the same model as in my boat, a couple of months ago, I helped carry in the 6 new batteries for him, they did not last long he said and was a bit disappointed in their performance.

We have some sockets on board that are only powered by shore power, while the rest are connected to the Victron Multiplus Compact 24/2000/50 inverter/charger which also charges the start batteries with 24V @4A the batteries are also VMF of 12V 680ccA so far they have fired up the engines in less than one revolution. There is a 50A 24V to 12V converter behind the fuse locker to provide for the 12V systems onboard.

Took a while to sort out with both the original installer and Victron and get the system to work properly, from everything I can now see I don't think there was much maintenance done on the boat between the owner passing away in 2020 and the estate getting the boat ready to sell in 2024, she had been stored out the water for over a year only going back in with two new propellors in May 2024 and we bought her in July 2024.

Next we want to put solar panels on but have not researched it properly yet.

 

[Skipper Felice]

Thank you ... it is good to see, that we all have +/- the same concerns ... and electrical problems ...
On my boat 3 owners within 25 years have done some or none or bad electrical systems installations - a lot of the things are fare away from professional nautic installations: I have to fix it now.

Lights and small consumers: Most of all lights are old 20W / 30W halogen >>> ALL will be replaced by 1W and 2W LED lightning with up to date electronics switching !!!

Solar panel: I have around 3 m2 of roof on the fly > I plan to add two good solar units and integrate it into the VICTRON charging system. On an good sunny day this will make around all power for instruments, lights and fridge! (0.3 kWh)

My open point are the batteries: VICTRON GEL? (expensive, top quality), Mastervolt?, Vetus?, BANNER (Austria), other brand ???

 

[Tranona]

Your charger at 30A seems a bit small for the size of your bank. As for batteries essentially you get what you pay for. Look at the cycles. Basic LA will be around 300, gel a bit more, AGM 500+. Important to fit a battery monitor so that you can log your consumption and state of charge. Keeping the discharge to roughly 50% capacity will extend the life. Reducing draw will obviously extend the period you can go without charge and solar will help replace the draw.

Difficult to recommend a make of battery as availability and prices vary from location to location, but Victron are generally considered overpriced. More important to look at the specs for the cycles. There are other things to look at, for example AGMs have a higher charge acceptance than FLA and gel plus lower discharge, so are arguably more suited to boats that are used for relatively short intense periods then left unused. there is no silver bullet. LA batteries are essentially consumables as they degrade through both use and non use.

 

[PaulRainbow]

Some experience and helpfull information - tips will be gratefully received.

On my boat - Azimut 46ft, year 2000, the last owner did not do god maintenance for the electrical system: I have to replace the whole battery and charger system.
The whole energy system should power the boat at anchor for 2-3 days. For offshore I can use the generator to recharge if needed.

Based on various information I will not go for lithium battery systems.

Given you need to replace all batteries and charging systems, this is a big mistake, in my opinion.

I plan to use VICTRON charger for shore connection (32A) / KOHLER gen. output 220V, 7kW. All management components from VICTRON.

The shore charger is not big enough for your systems, needs to be at least 70A, but stick with Victron. Personally, i would fit a charger/inverter, the Victron Multiplus 2 would be a good choice.

Whole system is 12V.
I will need 3 x 220Ah service batteries. (+/- 650Ah total) (deep cycle?)

You could almost get the same usable power from a single 314Ah Lithium battery, a pair would increase your available power considerable and cost much less than lead acid, take up half the space and weigh considerably less. Expect to pay £1200-£1500 for 3 x AGM or deep cycle.

I will need a new engine starter battery, high current, +/- 200 Ah (for Caterpillar 3208 engine)
I will need a new generater starter battery, high current, +/- 100 Ah (for KOHLER 7kW)

Starter batteries should be rated in CCA, not Ah. Any decent sealed lead acid will be fine.

 

[Skipper Felice]

Given you need to replace all batteries and charging systems, this is a big mistake, in my opinion.

... ....
Starter batteries should be rated in CCA, not Ah. Any decent sealed lead acid will be fine.

Dear Paul - thank you for your good sugestions:

Well, in my boat I have the 25 year old analogue carger from Azimut ... I think it destroys the batteries and does not charge ...
But I will think of the Victron charger/inverter, the Victron Multiplus 2. And yes I will look for a 70A charger.
The plan is to add the Victron manamgement system GX.

I just got the offer from a dealer in Italy, all components Victron, and Victron GEL batt. / What do you think?

 

[Sticky Fingers]

I’m surprised it’s 12V, not 24V.

 

[Skipper Felice]

I’m surprised it’s 12V, not 24V.

Yes - I think in 2000 most boats had been installed with 12V systems?
Our AZ46 is ALL 12V - all service devices 12V, fridge 12V. And on the other side there is a AC 220/230V system - power by shore connenction or KOHLER 7kW gen. set.
And someone has improved the aircondition: Only AC / 220V but 3 units (Cruiseair) 1 for salon, 1 general and 1 cabins with 3 zones controlled.

 

[Portofino]

Matteo from “ Doc Yacht “ on the marina will supply , fit and take away old batteries.
He will know a boat electrician too who will do as assessment first . Inc your charger .
This stuff is better accessed by a professional imho rather than random armchair key board warriors .

You new batteries need to dimensions wise - fit into the boxes and have the same pole positions for the connections.
Mail order or an out of town guy carries risks they won’t fit .
Matteo has 100 s in one of those garages by the sea wall ….his lock up .

We had a 120 AH Dolphin charger for 2x 180 Ah domestic and the same engine starters .
The original was a tiny 30 A .

These days modern chargers have multiple stages inc trickle - maintenance + many more . Tend to look after the batteries better than chargers of old .

Additionally your engine alternator (s) output needs figuring out …..so you have an idea of what’s going in the battery banks when running/ cruising .

There might be console gauges to indicate this ?

 

[Portofino]

Dear Paul - thank you for your good sugestions:

Well, in my boat I have the 25 year old analogue carger from Azimut ... I think it destroys the batteries and does not charge ...
But I will think of the Victron charger/inverter, the Victron Multiplus 2. And yes I will look for a 70A charger.
The plan is to add the Victron manamgement system GX.

I just got the offer from a dealer in Italy, all components Victron, and Victron GEL batt. / What do you think?
View attachment 196943

The failure mode of those original “25 year old chargers “ is not like a light bulb . Then don’t suddenly die thus alerting you . Instead they fade away slowly.
So when new it might have kicked out up to 30 A …..but it gradually drops off over time .

Before up grading my Itama to a 120 Ah it’s OEM 35 A h was maxing out kicking out only 4 Ah …..hence similar issues I guess you are experiencing?

As said get some one in to do a full diagnostic first , by the sounds of it buy a new charger and battery bank . Lead acid will be fine as long the charger is sized correctly.

 

[Tranona]

We had a 120 AH Dolphin charger for 2x 180 Ah domestic and the same engine starters .
The original was a tiny 30 A .

What is the point of a 120A charger on such a small battery bank? No way can the bank absorb that sort of charge. 30A is a bit small but a 40A would be more than adequate. Rule of thumb is 10% battery capacity which is why Paul suggested a 70A for the OPs larger bank.

There is nothing magic about replacing existing batteries and charger. No suggestion the system is inadequate so just a matter of choosing the right size and shape batteries (specs will show size and terminal layout) and decide the chemistry based on an assessment of the price/expected life ratio. Nothing to "diagnose"

Different if one were changing to lithium for example when it might make sense to involve a professional.

 

[Sticky Fingers]

Yes - I think in 2000 most boats had been installed with 12V systems?
Our AZ46 is ALL 12V - all service devices 12V, fridge 12V. And on the other side there is a AC 220/230V system - power by shore connenction or KOHLER 7kW gen. set.
And someone has improved the aircondition: Only AC / 220V but 3 units (Cruiseair) 1 for salon, 1 general and 1 cabins with 3 zones controlled.

Dunno, mine is a 1999 Princess 460, similar age and size to yours albeit mine has Volvos; it is 24V

 

[Portofino]

What is the point of a 120A charger on such a small battery bank? No way can the bank absorb that sort of charge. 30A is a bit small but a 40A would be more than adequate. Rule of thumb is 10% battery capacity which is why Paul suggested a 70A for the OPs larger bank.

There is nothing magic about replacing existing batteries and charger. No suggestion the system is inadequate so just a matter of choosing the right size and shape batteries (specs will show size and terminal layout) and decide the chemistry based on an assessment of the price/expected life ratio. Nothing to "diagnose"

Different if one were changing to lithium for example when it might make sense to involve a professional.

New ones are all singing + dancing various stages you can Google , as I said , it won’t over charge can’t .
Having said that I once saw it “ stuff “ in around 80 Ah then quickly iirc 15 mins or so ( don’t hang your hat on this figure ) it dropped . Remember It had 4 independent outlets . This would have been the domestic probably after a night @ anchor ? Geny running for breakfast etc . Or hooking up @ port in the evening after a night and day @ anchor , without the geny firing up .
That’s 80 into 360 for 15 mins …..not bad at all . A 1/4 ?
It soon dropped to 30 to 20 or what ever and eventually floated / trickled at around 3-4 ish . Never zero .

The size was something to do with getting one that works at a lower % of its potential in use . As opposed to a smaller working it nuts off in the very hot Med engine room ….when the boats not moving or engines running . Remember the massive 26 L in total engines when running even at low rpm would move a significant amount of air …think of it as a cooling draft through the ER .
How ever @ anchor or worse still berthed in a concrete marina with heat soak of the marina infrastructure + the iron engines ..= heat build up .
Prefer a big one taking it easy ,coping with its own fans running over a little one getting stressed out in the hot ER - Thinking longevity.

I didn’t spec it a boat sparky did ….after a full survey .

 

[Alicatt]

Dunno, mine is a 1999 Princess 460, similar age and size to yours albeit mine has Volvos; it is 24V

And mine is from 1978, it came with 24V and 12V for domestic and 24V start as standard from new, though the original batteries were 6V each, I have space for one more 12V 230Ah size battery in the battery tray which is under the galley floor.

Trying to revive the dud batteries, didn't work though.

 

[Sticky Fingers]

I’ve got one bank of 4x 12v in series/parallel for domestic, plus two banks of 2x12v in series for each engine start, plus a single 12v dedicated generator start, plus a bank of 2x12v in series for bow thruster. Victron AC (shore or generator) to 24V charger for domestics; CTEK AC (shore or generator) to 12V charger for gen start; DC-DC Victron charger for the bow thruster batteries; plus alternator charging for the engine start batts. I think I know what I’ve got but I’m very hazy on how it’s all connected up and charged.

No BMS.

I’d love some kind hearted volunteer to crawl all over it for an hour or two and draw it out.

 

[rafiki_]

I’ve got one bank of 4x 12v in series/parallel for domestic, plus two banks of 2x12v in series for each engine start, plus a single 12v dedicated generator start, plus a bank of 2x12v in series for bow thruster. Victron AC (shore or generator) to 24V charger for domestics; CTEK AC (shore or generator) to 12V charger for gen start; DC-DC Victron charger for the bow thruster batteries; plus alternator charging for the engine start batts. I think I know what I’ve got but I’m very hazy on how it’s all connected up and charged.

No BMS.

I’d love some kind hearted volunteer to crawl all over it for an hour or two and draw it out.

I could probably help?

 

[PaulRainbow]

Matteo from “ Doc Yacht “ on the marina will supply , fit and take away old batteries.
He will know a boat electrician too who will do as assessment first . Inc your charger .
This stuff is better accessed by a professional imho rather than random armchair key board warriors .

I am a professional. If "keyboard warriors" are excluded, best you don't post anything.

You new batteries need to dimensions wise - fit into the boxes and have the same pole positions for the connections.
Mail order or an out of town guy carries risks they won’t fit .

Is it not possible to measure them or look the make/models.

Matteo has 100 s in one of those garages by the sea wall ….his lock up .

So do all of the big sellers.

We had a 120 AH Dolphin charger for 2x 180 Ah domestic and the same engine starters .
The original was a tiny 30 A .

30A is about right for 360Ah, 120Ah is ridiculous.

These days modern chargers have multiple stages inc trickle - maintenance + many more . Tend to look after the batteries better than chargers of old .

Additionally your engine alternator (s) output needs figuring out …..so you have an idea of what’s going in the battery banks when running/ cruising .

There might be console gauges to indicate this ?

Why does he need to "figure out" his alternators ? They are what they are, he wants new batteries and chargers, that's all. No rocker science involved here.

 

[PaulRainbow]

The failure mode of those original “25 year old chargers “ is not like a light bulb . Then don’t suddenly die thus alerting you . Instead they fade away slowly.
So when new it might have kicked out up to 30 A …..but it gradually drops off over time .

Before up grading my Itama to a 120 Ah it’s OEM 35 A h was maxing out kicking out only 4 Ah …..hence similar issues I guess you are experiencing?

As said get some one in to do a full diagnostic first , by the sounds of it buy a new charger and battery bank . Lead acid will be fine as long the charger is sized correctly.

You need to learn the difference between amps and amp hours, plus correct charger sizing before giving keyboard warrior advice.

 

[PaulRainbow]

Dear Paul - thank you for your good sugestions:

Well, in my boat I have the 25 year old analogue carger from Azimut ... I think it destroys the batteries and does not charge ...
But I will think of the Victron charger/inverter, the Victron Multiplus 2. And yes I will look for a 70A charger.

A multiplus 2 would be a better choice than the Pheonix, you could use lower current AC equipment, such as the TV, radio, phone chargers, etc without running the generator.

The plan is to add the Victron manamgement system GX.

That's a good system, you can connect the charger or multiplus to it, solar controller too if you have one/fit one. You should also fit a smart shunt so you can monitor the batteries and chargers.

I just got the offer from a dealer in Italy, all components Victron, and Victron GEL batt. / What do you think?

Honestly, nearly 2.5K for 4 batteries is madness. 2 x 314Ah Lithium batteries (not Victron) would be vastly cheaper and give you more usable power, take up less space, weigh less and charge much, much faster. Not sure why you are so against Lithium, but if you're dead set against it, just fit cheaper lead acid batteries.