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bell ringer
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Discussion Starter #1
No one go crazy this is a real question and I am not looking for bent out of shape battles.

I need new house batteries and have 6 months to decide on them. I have been been pretty happy with my standard golf cart type of batteries. But will entertain improvements, which for me mostly is a true cost/life benefit. But here is what I am seeing as "advantages" given about changing to another type of battery.

Agms/Gels
- spillage/watering - not a problem to me to spend any money on
- faster charging - not that I can verify except at low state of charge and since my old golf cart T105s already accept as much power as my charger and solar can put out there isn't any advantage
- longer life - not that I can verify for the usage I do

LiPo/Lithium (whatever they are called)
- longer life - ok how much on a life amp-hour basis, do I have to plan on not getting a pay back for 5 years, 10 years, 15 years
- faster charging - well I already charge as fast as my charge sources can supply
- weight - my house batteries only weigh 250lbs, want difference to me is it if I could reduce it by half
- space - well yes if I freed up one of the battery storage spots that could be used, but I have lots of space on the boat still

sell me on a reason to upgrade from a $500 set of batteries that will last me 4 years at least, $10.40/mo, and not a hiuge cost
 

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Spending more money on

not having to water
**shorter** lifespan, adds to the cost per year

is up to you of course.

Faster charging? Might save 30min out of 6-8 hours, assuming the C-rate is high enough.
 

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LFP might get decades of use, but only if everything is right and nothing goes wrong.

Yes half the weight and space.

Yes much faster charging, down to 2 hours if you have the amps

even one, but that reduces lifespan.

At seven+ times the cost per usable Ah, likely more with infrastructure,

I'm not selling anything

again up to you if worth the cost / risk.
 

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sell me on a reason to upgrade from a $500 set of batteries that will last me 4 years at least, $10.40/mo, and not a hiuge cost
You've laid out your usage profile and reasoning many times over the past few years, and none of it has been factually or logically wrong for you.

Given your criteria and expectations, I'd go with what you had before - golf cart FLA batteries.

The one reasoning you left out of the LFP analysis is if you plan to run heavier loads off the battery. LFP has little voltage drop under load, so running higher loads means nothing to them. I assume your future usage won't change from the past?

On the other hand, one tends to run more heavy loads when LFP is present. We switched our water heater over to the inverter circuit and run it off batteries. We changed to a 30gph 120V watermaker from a 6gph DC one. With our increased solar, we can run our stateroom A/C overnight off the batteries.

Mark
 

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1C is much faster than I'd want any bank of mine charged, unless I really needed to for strong reasons.

Even if each such cycle only resulted in 0.001 reduced lifespan.

For those happy with only one decade and a few thousand cycles, if other care factors are coddled, then sure go for it, not very "damaging" I suppose.

But say an 800Ah bank

completely ignoring the bank itself or chemistry issues

800A infrastructure has its own safety challenges!
 

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bell ringer
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Discussion Starter #8
The one reasoning you left out of the LFP analysis is if you plan to run heavier loads off the battery. LFP has little voltage drop under load, so running higher loads means nothing to them. I assume your future usage won't change from the past?
Ok that may be a reasonable reason.

I can run my HW heater now off the house bank via the inverter. It takes 15 minutes at 130 amps to warm up enough for a comfortable shower. I have no plans to increase my house bank, and the solar to match it enough, to really run any inverter load more than this. I would think this is really not much load to a battery designed to run a golf cart.

I assume LFP is Lithium? How much would a 300AH total bank be? (yes I can look it up but bet someone just knows)*

* near as I tell from a quick search is that it would be $3k, at 3 years/$600 bank life that would take 15 years to break even
 

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I assume LFP is Lithium? How much would a 300AH total bank be? (yes I can look it up but bet someone just knows)*

* near as I tell from a quick search is that it would be $3k, at 3 years/$600 bank life that would take 15 years to break even
See my post here: https://www.sailnet.com/forums/electrical-systems/334018-2-000-battery-budget-t37.html#post2051677818

Yes, LFP = Lithium Iron Phosphate. There is no specific answer to price. It is kind of like "how much will LA batteries cost me". Many people are putting together 300Ah banks for less than $1k. Others are spending $10k. There are many variables and perceived qualities and marketing behind prices. Similar to building a 440Ah bank out of Trojan T105's vs. Sam's Club GC24's vs. Lifeline GPL4CT's. Same capacity, but what are the real differences to justify the large price deltas?

Mark
 

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1979 Morgan Out Island 41
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I went with AGM's because I'm horrible on routine maintenance items. The damage done by not watering costs me more than the difference in the AGM upgrade. Could I be a better person and pay attention to routine maintenance more? Sure. But I've got other things to focus on :)
 

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Don please read to the end. Just another way of thinking.
I want a pickup. Now have a new house and miss not having a pickup. Could get a beater fix or repair daily, or make use of the ridiculous deals on new vehicles. But decided to do nothing. Think the engineers are all over battery technology. Regardless of what this (USA) country does the rest of world is believers in man made climate change and doesn’t believe it’s in their national interest to be dependent on foreign countries for energy. The marine industry gets the spill over from truck/car tech.
I held off buying the latest and greatest thinking with prototypes and small run electric pickups already being made I’d wait for a electric pickup or at least a hybrid.
Think you should think the same. If you’re going to hang onto Hunter wait for an sale on AGMs. Good chance that’s coming soon as the economy continues to collapse or get a bunch of golfs if things go south sooner and you absolutely need batteries. If you are going to hang onto the boat for 5-10yrs. Fireflies then make some sense. If you’re going to hang on to the hunter until they throw dirt in your face or your Viking funeral go for the lithium if a good deal comes along.
If you think you’re going to move to another boat at some time in the future it’s real likely this conversation changes and a different battery chemistry will be available in a few years.
 

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I don't have any input for what someone should consider who is happy with what they have.

I can add a few things about the original pros/cons. Gels do not charge fast, in fact, they are slow in the upper ranges of charge. Their principal advantage is they are very durable and can take a occasional deep discharge cycle and bounce back, better than other lead chemistries.

Just because one's charger provides all the charge that a lead bank will accept, does not relate to other options. AGM will accept more charge, so you can get them refilled faster. All lead, however, lowers the amount of charge it will accept, as they approach higher states of charge. Lithium is the real leader here. It will take full throttle, until it nearly crosses the finish line. That mean one makes way more hay, while the sun shines.
 

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bell ringer
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Discussion Starter #14
Doesn't seem to me to matter if a battery COULD accept more if it is already accepting all that you can provide it.
 

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Don please read to the end.......
Thats not all of it
Charging requirements by type is a biggy...if you are on the hook for exrended times
Burn diesel/honda or not
Some batt types have strict charging demands

Not just cost of the batts
...and not just costs
The batts, chosen capacity, chosen charging...all dictate...your expected experience..and available options
 

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Doesn't seem to me to matter if a battery COULD accept more if it is already accepting all that you can provide it.
If you're saying your current charging system(s) can't put out more than your current batteries will accept, I understand. Not totally clear. Some charging systems throttle throttle back for what the battery will accept.

Raises another point, I think you understand. Changing chemistries will require a change in charging voltages and the in the case of lithium, requires an additional management system (which often come integrated with battery, but not on home grown setups). Even AGM would likely require a temperature controller on your alternator, if you don't have one.

If you're happy with what you have, as it's clearly a cost effective choice, I don't see you volunteering for anything different.
 

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If you’re living on the hook it’s your alt. energy production that permits you to avoid putting on the generator. Even in the tropics at noon with 20kts. blowing simple flooded Pb. will accept what you put out. It’s that last wee bit when the batteries are on float. However not a week goes by that you’re not on the boat for a day. Maybe off sightseeing or shopping or snorkeling. On that day you get the plates all the way up. You wake up with the house bank at 70-75%. By 10am you’re on float. By 2 pm on you’re conditioning the bank and getting rid of that last bit of sulfur. We typically show 13.4 when we come back to the boat. We leave some devices on so the boat is monitored (anchor alarm, other alarms, recording barometer, sometime AIS). Know people make a big deal abound rate of acceptance but in my personal experience it’s much to do about nothing. I can understand if you’re in a windless area with low sun angle and short days this calculus wouldn’t work. But Don’s in FLA so expect he sees the same thing. A more important advantage to Li or carbon foam is the abilities that draw down well past 50%. That is a biggie as Mark has pointed out. The second real advantage is weight. We have 1024 of lifelines I could half the weight if I got the lead out.
 

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.....Know people make a big deal abound rate of acceptance but in my personal experience it’s much to do about nothing.......
I agree that acceptance is unlikely much of a factor, when charging from wind or solar, as those sources are themselves typically limited. However, when you find the need to burn diesel to charge (alternator or generator), or simply want to get the maximum out of a short motoring passage, high acceptance rates of AGM or especially lithium, will be greatly more efficient than flooded or gel. Different cons apply, as have been disclosed already.

Lithium pricing is still an issue, unless you own long enough to amortize it back. However, it seems likely to be the future standard. Charge cceptance, weight, usable range of charge, cycle lifespan, etc.
 

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Should also mention in our circumstances and for many others the AC v DC for watermakers is another non issue. At least once every two weeks or so you have a boat day. Maybe diving the bottom or doing stainless or oils changes. So that day after breakfast and coffee you turn on the low output watermaker (we have two pumps so do alright). By the end of the day tanks are full. Sure there’s a concession. No evening music or TV or SSB chatting. You don’t have a work day when it’s airless, humid and wicked hot so no AC that day isn’t a biggie. Find we only want AC when out of the wind in a slip which is rare and then on shore power and not making water.
People should think about how they actually live before spending big money on things they may not actually need. You can’t always get what you want...but get what you need. Try sometime you just might find.....
 

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bell ringer
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Discussion Starter #20
The ability to drawn down the LFP batteries lower than the FLA I feel isn't an advantage unless you are space limited and do so regularly on your FLA. The past 4 years my 440H FLA bank was only down to 50% a few times, and that isn't a problem.

Acceptance doesn't seem an advantage to me if to get it I need to spend an extra $500-1000 on batteries AND then $1000-2000 to increase my charging. But I have no need to charge my batteries faster anyway.
 
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