gels or lithium for new

[SV Confianza]

Originally Posted by sailorboy1

Same thing far as you question. Don't let yourself get lost in the "noise" of the LFP installation when time comes. It is only complex and expensive if you want to make it a science experiment.

I’m sure everyone’s boat is different, but I did a bit of a test to see with my original stock Volvo alternator, internally regulated, on an md2040 to my lithium “drop in” bank. We were repowering anyway.

Not only would it charge excruciatingly slow, but I burned up the alternator in about 4 weeks. I also burned up another higher amperage alternator after fitting one of these, which is recommended by battleborn: https://battlebornbatteries.com/prod...ation-manager/

Also, excruciatingly slow charging.

I’m pretty convinced that unless you invest in a proper setup, at best you won’t be happy with it, and at worst it will be unreliable or even start a fire.

[sailorboy1]

Originally Posted by SV Confianza

I’m sure everyone’s boat is different, but I did a bit of a test to see with my original stock Volvo alternator, internally regulated, on an md2040 to my lithium “drop in” bank. We were repowering anyway.

Not only would it charge excruciatingly slow, but I burned up the alternator in about 4 weeks. I also burned up another higher amperage alternator after fitting one of these, which is recommended by battleborn: https://battlebornbatteries.com/prod...ation-manager/

Also, excruciatingly slow charging.

I’m pretty convinced that unless you invest in a proper setup, at best you won’t be happy with it, and at worst it will be unreliable or even start a fire.

Sounds your system sucked to start with. I have made no changes to my boat and have had the LFP 7 months. But then you couldn't get by with 6ooah of house bank and get by with less with no issues.

[Adelie]

Originally Posted by SV Confianza

I’m sure everyone’s boat is different, but I did a bit of a test to see with my original stock Volvo alternator, internally regulated, on an md2040 to my lithium “drop in” bank. We were repowering anyway.



Not only would it charge excruciatingly slow, but I burned up the alternator in about 4 weeks. I also burned up another higher amperage alternator after fitting one of these, which is recommended by battleborn: https://battlebornbatteries.com/prod...ation-manager/



Also, excruciatingly slow charging.



I’m pretty convinced that unless you invest in a proper setup, at best you won’t be happy with it, and at worst it will be unreliable or even start a fire.

What is a high amperage alternator to you?
How slow is slow and for how many Amp-hours?

[Senojev]

There is- good short Victron video showing the standard alternator versus an externally regulated alternator charging a lithium battery.

https://m.youtube.com/watch?v=jgoIocPgOug

[dhenline]

I guess the reason I would be schocked if five batteries are not enough, is that they will be charging most days with the solar that is being installed (1600 watts I believe) which should help charge the batteries during the day and then if the generator is run most night for AC, how could I possibly NOT keep the batteries well charged.
I am not super familiar with this aspect of sailing but when I rent Cats in the Caribbean, they usually dont have solar and just running the AC at night, mostly keeps the batteries charged.
in addition, I will have to run the Geny sometimes during the day to refill the dive tanks and of course running the engine will also help.

I will likely try the included house bank for a year and see how it goes. Maybe I will be surprised. But I mostly am doing it because of the idea that I have already paid for the batteries, so why just throw them out .

[ranger58sb]

Originally Posted by dhenline

I likely have made a mistake in my question. The Batteries are AGM batteries and yes there are five of them (there is a sixth one that I believe is supposed to be for The electric winch). I assume they are linked together.
they are rated for 140/ Ah. So I guess that will give me 700 Ah for the batteries. Or about 350 usable at 50 % draw. I have heard that AGM can withstand 80 % draw but unconfirmed.

I apologize for using the terms gel and AGM interchangeably

My thought would stay the same: get the boat with standard OEM batteries, use those until replacement is necessary, think about it all over that time period to inform your decision for follow-on change. Or not. If they're decent batteries, you could get maybe 5-10 years from those...

Maybe don't assume all 5 of those are linked together. You could track that down for better clarity. Your first note said 5 for house, one for electric winches, one for each engine. Could well be one of the 5 is instead for an electric windlass (one of the 5?) or for bow thrusters (maybe not common in cats). Or maybe one for electronics. Et cetera. IOW, it could be 4 for house, and then singles for all those other functions.

If it turns out your house bank is 4x 140-Ah batteries... 560-Ah at 12VDC isn't chump change. And AGMs do at least have an advantage of higher charge acceptance rate (relative to flooded)... assuming the charger is capable. And there's that solar...

Odyssey ($$$$) sometimes advertises 80% DoD is OK... but in general the AGM makers that publish a life cycle chart show the same longevity as flooded lead-acid deep cycle batteries... and 1000 cycles to 50% DoD is a common goal. Number of cycles to 80% DoD much lower. (Lifeline's chart is representative; see the manual from their website.) I think the 80% thing is sometime meant to indicate actual damage won't occur, not a recommendation to routinely cycle that low.

-Chris

[dhenline]

thanks everyone for the replies.
For now I am going to go with the standard batteries.
If I am unhappy with them, I can always change that.
I will have alot of solar on this boat so I will just see what happens
I will eventually report back however I am not scheduled to pick up the boat until
May of 2024 in La Rochelle france

[sailorboy1]

Originally Posted by dhenline

I will likely try the included house bank for a year and see how it goes. Maybe I will be surprised. But I mostly am doing it because of the idea that I have already paid for the batteries, so why just throw them out .

100%

bet you use them for years

[sailingharry]

I really think you will be pleased.

We have 750 Ah of AGM on our 43 ft mono. We have fridge, freezer, normal electronics, and we make coffee and toast each morning with electric appliances. We burn 2 to 300 ah of energy a day.

Solar is ideally suited to AGM. LFP can be charged in a short time with very high charge rates, making an alternator an ideal charge source for LFP (and painful with AGM. I can charge at as much as 3kW, but never run my engine long enough to get the AGM charged. With LFP that same alternator would fill my daily load in 1-2 hours). But AGM requires slow and steady to get to 100%. This is where solar works brilliantly. You should have the batteries up over 80% before noon, and then the rest of the day to get very close to 100%. 1500W should make about 4.5 kW/day, and you should consume under 3kW/day. And that's without ever running the generator for a/c.

[sailorboy1]

The thing with that and all lead acid batteries is that as the batteries get charged they stop accepting all that solar can send them. It is a waste of lost power production. Meanwhile the LFP would just keep taking all the solar can sent it till like 98% SOC.

But it doesn't really matter as long as you can keep up with use.

[SV Confianza]

Originally Posted by Adelie

What is a high amperage alternator to you?
How slow is slow and for how many Amp-hours?

This was a couple of years ago, so I can’t say I have exact data. I had two 120 amp alternators (now we have two small case 170s) and the agm batteries would take like 4 hours to get a half charge.

If you’re only able to use 50% of the batteries (without killing the lifespan), and then a significant portion of your charging time is absorption phase, the time to charge was forever.

And on a cat, 500ah of agm was just woefully inadequate. That was even before we got power hungry things like a toaster. I don’t even think the rest of our systems could run with the power draw of the toaster plus 2 MacBook Pro 16s charging with agm. The MacBooks plus the toaster draw as much as our windlass.

The fridge and the freezer alone were using a measurable amount of the usable capacity.

Now that we have lithium, we upgraded the solar, and can even run our air conditioner a few hours a day off the bats. But before even going that far, the lithium completely changed how we think about power on the boat.

Angie and I work and live on the boat full time, and on rainy days maybe we run the engine for an 1-2 hours to top up. We got rid of the generator years ago.

The switch to lithium is just a whole different experience. I can only speak for us, but we would definitely never go back.

[Simi 60]

Cats hate weight
Go the Lifepo4 from day one and save weight

[Simi 60]

Originally Posted by SV Confianza

.

And on a cat, 500ah of agm was just woefully inadequate. .

Do cats magically use more electrickery than other types of vessel?

[fxykty]

Originally Posted by Simi 60

Do cats magically use more electrickery than other types of vessel?

Just like your launch, most cats support a more land-life like lifestyle due to their space and stability. That increases electricity usage. Plus a plethora of solar reduces the urge for conservation.

Our cat came from the factory 20 years ago with AGM 6x110 Ah at 12V and only 600W of solar panels. The original owner added a generator and another 400W solar after they started cruising full time. It seemed barely adequate after the first few years of our ownership and as we gained longer term cruising experience we knew we wanted more power. We’ve now got 700Ah at 12V of LFP with 2600W solar, removed the generator, added higher output alternators, and converted to an electric galley. And we’re about to double our battery capacity. I guess we’re power hogs.

For the OP, sticking with the existing batteries is the right call. They will likely last 5-8 years, certainly long enough to decide whether they’re not suitable for how the OP wants to use their boat.

[Senojev]

Originally Posted by sailorboy1

The thing with that and all lead acid batteries is that as the batteries get charged they stop accepting all that solar can send them. It is a waste of lost power production. Meanwhile the LFP would just keep taking all the solar can sent it till like 98% SOC.

But it doesn't really matter as long as you can keep up with use.

That’s when you turn the water heater on and cook meals ahead