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I’m not advocating outright abuse. We are constantly charging with wind and solar. Not to mention gen or engine as the situation requires. And I’ll be moving my radar to remove some shadow.

But it is what it is and I’m not going to stress about it over a certain point.
 

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No hard-edged defining lines here, it's all greyscale and judgement calls, long as we're basing decisions on solid known principals, best that anyone can expect
 

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Discussion Starter #64
I am curious if anyone has any experience with EFOY fuel cells for charging. They look like a pretty appealing clean energy source in a compact package, albeit a bit on the pricey side.

Sent from my SM-G960W using Tapatalk
 

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We've got 6-6volt Lifeline AGM for720 ah. Daily diet in mid summer with refrigeration running is 65 ah. That includes many LED , radar and chartplotter and charging of phones etc. Caframo fans (3) and refrigeration use most of power. Don't forget the pumps etc. 360 usable ah. We never worry about electricity. Alternator is a 100 amp Balmar with ACR regulator .
AGM charge more quickly...but more expensive. Wilth proper equilization they have lasted 9-10 years and 500 cycles. That more thann covers their added exp see need of AGM.

The new lithium are super expensive and worth it if your sailing is mainly cruising or you switch from a desiel engine to electric. For most of us this type of battery is not cost effective.
I switched from diesel to electric auxiliary propulsion in 2008 and am still not seeing the need and expense to go to Lithium. My house bank is two group 27 Gel Cells that are still going strong after 11 years. I used Gel Cells because that was one of the two choices my Pro Mariner battery charger offered for charge profiles. The other was for Flooded Lead Acid. I think the main reason why my house batteries have lasted so long is because they have never been charged by anything but the Pro Mariner charger and a solar controller. Never from and engine driven alternator.
 

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I switched from diesel to electric auxiliary propulsion in 2008 and am still not seeing the need and expense to go to Lithium. My house bank is two group 27 Gel Cells that are still going strong after 11 years. I used Gel Cells because that was one of the two choices my Pro Mariner battery charger offered for charge profiles. The other was for Flooded Lead Acid. I think the main reason why my house batteries have lasted so long is because they have never been charged by anything but the Pro Mariner charger and a solar controller. Never from and engine driven alternator.
Here's something I never understood: I understand that Lithium batteries make sense for cars etc because of the weight and energy density.

But for sailboats? We CRAVE weight, the keel of my boat is a blob of lead that is literally heavier than the rest of the boat.

Why don't we build a keel out of the cheapest, heaviest lead acid batteries and all go electric? Yes we need to make sure it does not flood but we are pretty good at making things waterproof (like boat hulls).

Maybe this is a topic for a separate thread?
 

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Gel cells are well-known for their lifespans. The downsides are very narrow charge voltage limitations (one modestly high voltage event can trash them), and they have relatively low charge acceptance rates, as well as relatively low discharge rates - so charging them fully takes longer than other types, and using them for high currents isn't ideal.

Two Group 27's is a small bank, and implies that your electric propulsion needs are modest. For a larger need, high charge acceptance rates becomes important because one needs to put a lot of current back into the batteries before next use. Or one needs longer times between usage to achieve full charge.

Lithium really shines in this application because it recharges as quickly as you can throw current at it, and it is happy to operate forever at partial states of charge if you can't throw enough current at it.

For a continually cruised, large boat, with modest off-grid charging capabilities, lithium becomes the only realistic way of achieving this goal. It is still a tough goal to reach, though. I'd really like electric propulsion to be more generally mainstream, but as it stands today, it is really only for smaller boats that are more lightly used (propulsion-wise).

Mark
 

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Here's something I never understood: I understand that Lithium batteries make sense for cars etc because of the weight and energy density.

But for sailboats? We CRAVE weight, the keel of my boat is a blob of lead that is literally heavier than the rest of the boat.

Why don't we build a keel out of the cheapest, heaviest lead acid batteries and all go electric? Yes we need to make sure it does not flood but we are pretty good at making things waterproof (like boat hulls).

Maybe this is a topic for a separate thread?
Um, some of us don't crave weight - just the opposite. Others who can handle weight don't want it in the places batteries are usually stored. In fact, you might be the only person I've heard of that craves more weight on their boat.

Lithium has advantages other than light weight. The real game-changer for them is the ability to operate their entire lives in a partial state of charge - no need to ever charge them fully just to keep them from destroying themselves. In other words, if you have enough juice in them to make it through the day, you don't need to charge - and this goes on ad infinitum. Then you have the ability to charge them as fast as you can throw current at them - this significantly cuts down on charging time. Replacing 100Ah with a 100Ah charger takes 1hr - where it will take 6-8hrs with a lead battery.

Mark
 

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Here's something I never understood: I understand that Lithium batteries make sense for cars etc because of the weight and energy density.

But for sailboats? We CRAVE weight, the keel of my boat is a blob of lead that is literally heavier than the rest of the boat.

Why don't we build a keel out of the cheapest, heaviest lead acid batteries and all go electric? Yes we need to make sure it does not flood but we are pretty good at making things waterproof (like boat hulls).

Maybe this is a topic for a separate thread?
If one were designing a boat from the ground up that would make sense. In my boats case I was getting rid of a 424 pound Westerbeke diesel plus another thirty gallons of fuel and an engine battery. It made sense for me to put the electric propulsion battery bank on a platform in the area where the engine use to rest. Even so I still cut 100 pounds of weight off the boat with the install.
 

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Two Group 27's is a small bank, and implies that your electric propulsion needs are modest. For a larger need, high charge acceptance rates becomes important because one needs to put a lot of current back into the batteries before next use. Or one needs longer times between usage to achieve full charge.
Those two group 27 batteries are just for my 12 volt house bank. I also have four 8A4D AGM batteries for my Electric Propulsion bank. It has it's own charging systems which includes solar, wind and my Honda 2000 generator. Also I can use 120 volts AC if I'm at a dock which is rarely.

One nice thing about having the 10KW Electric Propulsion bank in addition to my house bank is I can tap into if needed while at anchor. Which I do from time to time. I use my 1600 watt 48 volt inverter to use my bread maker. Nothing like the smell and having fresh bread when you wake up in the morning at anchor.
 

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Those two group 27 batteries are just for my 12 volt house bank. I also have four 8A4D AGM batteries for my Electric Propulsion bank. It has it's own charging systems which includes solar, wind and my Honda 2000 generator. Also I can use 120 volts AC if I'm at a dock which is rarely.
Ah, that makes more sense. I was thinking you had a trolling motor or something similar! I now see I missed that in your original post, and conflated your house bank with your propulsion bank.

Mark
 

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Bored, can’t sleep. Just looked up prices of Lithium batteries, GC2. The cheapest I saw was over $2,000 per batterie. So I would be looking at about $10,000 for my house bank of 4 GC2 batteries? Really? What am I doing wrong?
 

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....We CRAVE weight, the keel of my boat is a blob of lead that is literally heavier than the rest of the boat.

Why don't we build a keel out of the cheapest, heaviest lead acid batteries and all go electric? .......
I don't know about craving weight, but keel boats certainly have tons of weight intentionally added for ballast. I get the desire to swap it for something with dual purpose. I think there are two limitations for adding batteries to the keel. Nothing on a boat is actually waterproof, including the hull. We all get some sort of leak eventually. Further, no two keels are alike. This would make manufacturing efficiency very difficult and very expensive.

It would be nice to see an effective long range electric solution, but it's not in the cards with current technology. Actually, most of the advancements in both batteries and charging (solar/wind) have been in manufacturing efficiency, not storage capability. The energy density, therefore storage of potential energy, of carbon based fuels can't be beat so far.
 

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Bored, can’t sleep. Just looked up prices of Lithium batteries, GC2. The cheapest I saw was over $2,000 per batterie. So I would be looking at about $10,000 for my house bank of 4 GC2 batteries? Really? What am I doing wrong?
I'm not sure where you are looking, but there is hardly a typical group size on the site linked below that is near that price level. Not many sailboats use 8Ds. Maybe your battery size is the unusual variable and there is a near match that is more affordable.

I currently have 4x Group 31 Gel batteries at approx 100ah each, which cost approx $475 each. That was a total of $1,900 for 200ah of usable capacity (50% of total capacity).

If I were to upgrade to lithium, the attached shows Group 31 lithiumPO batteries at $1,050 each and the same 100ah total capacity in each. However, you can run a LifePO battery down to 20% SOC, so that's 100x4x80% or 320ah of usable capacity for $4,200.

At least for this brand, lithium is twice the cost, but one gets 50% more usable capacity, superior charging profile (ie much less generator/engine time or faster renewable charging) and they weigh about a third of what the Gels weigh.

It would be cheaper to add even more weight and batteries, but for those who are space or weight constrained or value the faster charge rate, lithium has value.

https://www.coastalclimatecontrol.com/index.php/batteries/lithium-iron-phosphate-battery.html
 

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GC2 batteries are “Golf Cart” batteries.

I did a little more looking and found some Lithium as low as $1,100.

Batteries Plus sell lead acid GC2 batteries for $110 - $130.

So look at it this way, if I get 3 years from a set of batteries I get 30 years of battery per pocket book charge.

The lithium batteries would have to last 30 years to be equal.

That’s probably being a bit facetious and I’m sure there are other advantageous BUT...

HOLY COW THATS A LOT OF MONEY!
 

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Comparing the cost of LFP to FLA is a bit of apples and oranges, although they both store energy. A better comparison would be to gel or agm, because at least then you will be comparing physical and operating features like no maintenance, etc.

Consider one aspect of the cost of LFP to be similar to the cost of a watermaker - it is almost always cheaper, even in the long run, to buy and jug water than to get a watermaker. But people cruising still fork over thousands for a watermaker by the droves for very good reasons other than cost. LFP has the same rationale from a general overhead viewpoint, ignoring the details of why.

Not included in most cost comparisons is that it takes less solar and less fuel to recharge LFP.

Replacing batteries often can be inconvenient and expensive. We had to replace a GC house bank in Panama once. Battery prices for flooded golf cart batteries there cost 75% of what our equivalent capacity LFP bank cost. AGM prices in Panama were 3x that, so much more than LFP. And we had to interrupt our cruise to go back to Panama to get them. We had to buy a simple, common automotive start battery in the Bahamas. That one cost $200 - I can't imagine what a house bank of reasonable batteries would cost there, but it would surely be more than a LFP bank.

If money is the sole, or overriding, consideration, then flooded golf cart batteries can't be beat. If one is not cruising or living full-time off grid, then LFP doesn't make as much sense.

Mark
 

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GC2 batteries are “Golf Cart” batteries.

I did a little more looking and found some Lithium as low as $1,100.

Batteries Plus sell lead acid GC2 batteries for $110 - $130.

So look at it this way, if I get 3 years from a set of batteries I get 30 years of battery per pocket book charge.

The lithium batteries would have to last 30 years to be equal.

That’s probably being a bit facetious and I’m sure there are other advantageous BUT...

HOLY COW THATS A LOT OF MONEY!
No I don't think you are wrong in your skepticism on a Lithium conversion. Even if the 2000 charge cycles of Lithium batteries holds up. I won't live long enough to see if they actually do. :) It's been said most cruising boats spend 90% on their time at anchor. I certainly do. I head some place and hang out anywhere from a few days to a week. Since I do have a SAILBOAT usually my boats EP bank just needs a little top off. Solar and wind maintain it after that even if I do tap into it's energy from time to time.

Another thing you need to add to the costs of Lithium is the Battery Charger and the BMS (Battery Management System) needed to protect the cells from over/under charging. When I converted 11 years ago to EP I bought a second backup AGM battery charger (which I have never needed) so I've got a little more invested if I were to change now too. Personally the complexity needed to maintain a Lithium Battery bank scares me. AGM'S are easy to understand and figure out without additional circuitry needed to maintain them. What can I say I'm just a KISS (Keep It Simple Sailor) :)
 

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Um, some of us don't crave weight - just the opposite. Others who can handle weight don't want it in the places batteries are usually stored. In fact, you might be the only person I've heard of that craves more weight on their boat.

Mark
Really? Wouldn't a heavier keel improve pretty much every monohull's performance? Am I the only one who likes better sailing quality?
 
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