Lithium iron phosphate batteries on sale

[twistedtree]

Thank You!

Of all the people here I have learned over time to trust and respect your knowledge of electrical systems.

Thanks. Very kind of you.

 

[Simi 60]

You guys are assuming that you are actually charging beyond 80% which most folks on the hook with FLA batteries do not do if they understand FLA charging.

My argument is valid electrically. If you operatye your FLA bank in the approx 50-80% SOC range most will never be able to exceed the charge capabilities of a reasonable FLA bank using off the shelf charging equipment.

We are AGM but get to 100% by midday yet still have 2500 watts of solar doing its thing so I am guessing we get there
Batts have only got below 80% once since install on about day 3 after initial install 4 years ago.
Hoping they have a good life

 

[catalinajack]

Ksanders, no, we "guys", most of us anyway, fully understand that getting beyond 80% takes awhile. But, so what. Many cruise for a very long time (6-8 hours and with a couple of 100+ amp alternators can, and do, fully recharge their batteries. Many boaters spend no more than three consecutive nights on the hook and recharge fully at the next marina stop. My point is that lithium is the answer for some boaters while for others FLA works just fine and is far more cost effective for that user profile. I, for one, do not angst over depleting my FLA bank down to 40 or 30 percent occasionally thus shortening their useful life a bit. Again, so what.

You guys are assuming that you are actually charging beyond 80% which most folks on the hook with FLA batteries do not do if they understand FLA charging.

My argument is valid electrically. If you operatye your FLA bank in the approx 50-80% SOC range most will never be able to exceed the charge capabilities of a reasonable FLA bank using off the shelf charging equipment.

BTW my crown 430 AH batteries recommend a maximum of 100A charge current. That means that two parallel strings are 200A. Few chargers have excess of that capability.

Remember that evey watt of energy used out of a battery bank needs to be replaced. If you are operating your bank to maximize your chargers capability when running on generator you are not going to avhieve better results than that, regardless of the technology of the batteries. Thus you are not saving generator run time.

Admittedly if you have the same size bank of LifeP04 batteries as FLA batteries you can run your generator longer to replace those watts used, and go longer between generator run times, but you will not shorten the total time you need to run the generator.

The problem with that is few people replace a 800AH FLA bank with a 800AH LiFeP04 bank. They tend to go smaller because of cost, etc...

Then consider this... On a FLA bank that is operated normally between 50 and 80% you have the capability to occasionally go all the way to zero or close to it without affecting the overall longevity of your bank. For example if you are planning to be underway and using your main engine alternator you might not run your generator at all, just discharge below 50% and catch up using your main engine while underway.

You Do Not have that luxury with Life P04 because you typically operate in the 20-100% range, meaning you have no reserve cushion to fall back on, since it is simply not there.

 

[Iggy]

No one has mentioned that the your charger will need to be changed out. To one that can handle the new chemistry.

I thought about changing over, but the cost to me is still high. I am hoping in the next few years the cost will go down.

 

[Hippocampus]

Lifelines are expensive. If any brand of LA isn’t brought up to 100% periodically service life is markly decreased. We got 7 years out of our Lifelines and they had lost less than 10% on load testing at that point. But had 1020 of capacity. Cycled down to 80% most days. Never below 65%. And that was less than maybe 6 times in 7 years.With solar and wind brought to 100% at least weekly. Most days alt energy covered our daily use. We lived on the hook.
Now Pb means major restrictions in how many useable amps you really have with any brand of LA be it AGM or flooded. That’s where Firefly or Li shine. You get a massive increase in useable amps and don’t meaningly impact service life by not getting to 100%.
Still, there’s no free lunch. You need to get amps into any bank if you’re getting amps out. Here your use pattern matters determines what you need for charging. If you are going to live full time on the hook choices are solar, wind, generator. More solar/wind less generator. Period. No getting around it.
If you short hop what you have for alternators is what matters. Why bother with other stuff if your useable amps in the bank are sufficient.
If you’re usually on shore power the whole question is moot.
Most of us have something around 8 from our gensets. They usually go on for AC, watermakers, refrigeration and such. After start up there’s usually plenty left. Now think about how often and for how long you’d run the genset for a reason other than battery charging. So production isn’t the issue. Invertor/battery charger capacity should be informed by how you actually use + live on the boat not abstract math.

 

[boathealer]

No one has mentioned that the your charger will need to be changed out. To one that can handle the new chemistry.

I thought about changing over, but the cost to me is still high. I am hoping in the next few years the cost will go down.

I think this used to be true. But with the advent of newer, smarter, BMS hardware/software right on each battery it is less likely - especially if you can customize voltage thresholds in your existing charger.

From RELiON:

"How to Charge a Lithium Iron Phosphate Battery

The ideal way to charge a LiFePO4 battery is with a lithium iron phosphate battery charger, as it will be programmed with the appropriate voltage limits. Most lead-acid battery chargers will do the job just fine. AGM and GEL charge profiles typically fall within the voltage limits of a lithium iron phosphate battery. Wet lead-acid battery chargers tend to have a higher voltage limit, which may cause the Battery Management System (BMS) to go into protection mode. This won’t harm the battery, however, it may cause fault codes on the charger display."

 

[twistedtree]

My point is that lithium is the answer for some boaters while for others FLA works just fine and is far more cost effective for that user profile. I, for one, do not angst over depleting my FLA bank down to 40 or 30 percent occasionally thus shortening their useful life a bit. Again, so what.

I agree that how you use your boat makes a big difference, and then in that context, what you care about.


Much of this has been discussed, but what I personally like about LFP is:


- There is no taper over the last 40% of the charge cycle. With LA, 50% to 80% SOC (60% of the charge cycle) will happen at full charger output, but 80% to 100% SOC (40% of the charge cycle) will be at reduced charger output. With LFP, the full charge cycle (say 20% to 100% SOC) happens at full charger output. That's faster charging, and better generator utilization.



- I can build a bigger charging system, and thereby further reduce gen run time, and better utilize the generator when I do run it


- I don't have to make sure I fully recharge them every few days, or worry about how long it's been since the last full charge.


- When I do recharge, it can be as little or as much as I want.


- I like not having lead and sulfuric acid on the boat


- I like their more compact size.



- They are 95+% efficient, so little heating, and goes in comes back out (mostly)


- In a nut shell, they are about as "set it and forget it" as can be.


- I'm willing to pay more for this. In my case it was about a 50% premium over AGMs, which are of course a premium over FLA.

 

[Tator]

Here's another consideration in my particular situation for considering switching to LiFePO4s. My current house bank is located outside of the engine room in a compartment that stays at 50deg F. At that temperature, according to Trojan, my FLAs lose 20% of their capacity. My 1100 ah bank becomes 880ah. At a 50% DOD, I only have 264ahs before reaching 80% DOD. With a smaller LiFePO4 bank (I'm thinking 420 ah) I can move it to a compartment that stays about 60deg F and is also closer to my inverter/charger and buss bars.

Tator

 

[Comodave]

Here's another consideration in my particular situation for considering switching to LiFePO4s. My current house bank is located outside of the engine room in a compartment that stays at 50deg F. At that temperature, according to Trojan, my FLAs lose 20% of their capacity. My 1100 ah bank becomes 880ah. At a 50% DOD, I only have 264ahs before reaching 80% DOD. With a smaller LiFePO4 bank (I'm thinking 420 ah) I can move it to a compartment that stays about 60deg F and is also closer to my inverter/charger and buss bars.

Tator

I shortened the cable lengths by about 4’. That doesn’t sound like a lot but every little bit helps. I have 3 of the Lion batteries so I will have 315 AHs in the bank. And I can use almost all of it if needed. I am replacing 4 6 volt GC batteries that had about 190 AHs of usable capacity. So smaller lighter batteries and I will have about 125 more AHs available.

 

[twistedtree]

Here's another consideration in my particular situation for considering switching to LiFePO4s. My current house bank is located outside of the engine room in a compartment that stays at 50deg F. At that temperature, according to Trojan, my FLAs lose 20% of their capacity. My 1100 ah bank becomes 880ah. At a 50% DOD, I only have 264ahs before reaching 80% DOD. With a smaller LiFePO4 bank (I'm thinking 420 ah) I can move it to a compartment that stays about 60deg F and is also closer to my inverter/charger and buss bars.

Tator

Those do sound like improvements.


Another thing that hasn't come up is the Peukert exponent for LFP vs LA. This is how much effective capacity you lose when discharge rates are high. With LFP, the exponent is effectively 1, meaning you get full battery capacity regardless of discharge rate. Now I say this in the context of a house battery bank where discharge rates are expected to be 1C or less, and usually a good bit less.


So if your use has higher loads for anything other than a brief moment, LFP will have an advantage is actual usable capacity.

 

[Hippocampus]

TT what did you spec in your new Nordhavn?
On a new to you boat fireflies are very appealing but for a new build would think Li is the way to go. What was your decision and why?tx.

 

[boathealer]

A bit of comparison/research I did last night as my AGM bank (top left) is 6 years in....

 

[twistedtree]

TT what did you spec in your new Nordhavn?
On a new to you boat fireflies are very appealing but for a new build would think Li is the way to go. What was your decision and why?tx.

I've put together a battery system using MG Energy. It's batteries with internal monitoring, connected to an external BMS and emergency contactor. They were the supplier of Victron's higher-end LFP system until Victron started building their own slightly lower end products. I've met the principals, been to their facility, and am very impressed by what they have done. I also built it up as two identical, parallel banks+BMS for redundancy. Early on learning about LFP I was pretty spooked by the prospect of a failure taking out the boat's DC power system, which would be pretty bad. I'm less concerned about that now that I have going on 2 years of operation with LFP. But it gives peace of mind, and the second BMS only increased the cost by about 5%.


I think the Firefly batteries are very interesting, and very promising, but also an in-between solution that is destine to get squeezed out of the market by FLA (cheapest) on one side, and LFP (best function and performance) on the other side. Also, LFP had been around for a long time, and has been studied and tested every possible way you could imagine. Firefly's are one company, much newer, with way less study and data. So I think LFP are a far more proven technology, which I like on a boat. So I picked what I think is the better long term solution, and the more proven solution.


And I agree with your point (implied) that the considerations are very different for a retrofit vs a new build. And retrofits will vary widely from boat to boat. So the whole project has to be considered in making a choice. Firelfy's have great appeal for retro fits, as do drop in LFP.

 

[Gordon J]

Not exactly the whole story

That is the part of the equation that most seem to either not understand or ignore.

A four battery bank of FLA L16 batteries will depending on the brand be right at or a bit over 800 amp hours in capacity, and accept a charge current of 200 amps.

Remember this is charge current so add your boats loads to that and you will then know your charger requirements to maximize this.

Now, how many of us have charge capability exceeding this?

My opinion darn few indeed.

Myself I have TWO Victron multiplus units running in parallel for a total charge capability of 240 amps. This barely amounts to the charge maximum on my FLA battery bank, so going to LIFeP04 will not save me generator run time.

BUT... Internet mythology and great salesmanship is fueling spending charging system upgrades, and that is a good thing.

My argument is and has been that a properly designed charging system will minimize generator run time, not simply the choice in LifeP04 batteries over competing technologies.

Take the same properly designed charging system, and use FLA batteries and in most cases you will achieve the same results if the goal is to minimize generator run time.

Kevin,

Charging times will be reduced on lithium because their charge acceptance rate is higher. That last 10 - 20 percent will go as quickly as the first 30 percent. Fire flys take a long time to get to 100 percent, and their charge acceptance rate is higher than that of standard AGM.

Gordon

 

[Gordon J]

That’s the beauty of carbon foam

Agreed if you only charge through bulk ~80%.

It’s small, but LFP is also 95+% efficient round trip, with LA in the 80-90% range. So a slight difference there.

They don’t care if you go down to 30 or 20 percent state of charge. You can’t hurt them. Deeper discharge does mean fewer cycles remaining in the batteries, but with more than 3500 cycles, I don’t care.

After being on the hook all night with my energy hungry boat, I now find that I am back at 100 percent after a day of motoring. This did not happen with AGM batteries.

Gordon

 

[twistedtree]

They don’t care if you go down to 30 or 20 percent state of charge. You can’t hurt them. Deeper discharge does mean fewer cycles remaining in the batteries, but with more than 3500 cycles, I don’t care.

After being on the hook all night with my energy hungry boat, I now find that I am back at 100 percent after a day of motoring. This did not happen with AGM batteries.

Gordon

That comment was a reply to an earlier post regarding FLA, not FireFly's. And it answers you last question/comment about absorb charge rates. On generator, he only charges through bulk mode, so acceptance rate is charger limited, not battery limited, just like for LFP. He gets around the absorption taper by just not doing it until he gets back to dock, or has a run long enough to fully recharge.

 

[DDW]

I think the technology window on Fireflys is closing fast, or has closed. You can get LFP now at nearly the same or the same $/AH. I can see very few advantages of Firefly over LFP, and many advantages of LFP over Firefly. I needed new batteries and intended to replace them last spring with either AGM or Firefly, but Covid intervened. At this point the price on LFP have dropped to be competitive with Firefly, both are still a premium over Lifeline AGM but with substantial benefits in the bargain, while being substantially cheaper in lifecycle cost.

 

[Comodave]

I got my LiFePO4 Lion Energy batteries form Costco on sale, 2 for $1400. Someone said they are back on sale now, but I haven’t checked since I have mine now.

 

[cardude01]

Firefly article I ran across recently. Does this hold true for LFP batteries also?

https://www.morganscloud.com/2020/1...-batteries-are-great-but-read-the-fine-print/

 

[twistedtree]

Firefly article I ran across recently. Does this hold true for LFP batteries also?

https://www.morganscloud.com/2020/1...-batteries-are-great-but-read-the-fine-print/

I'd say Yes, and No. The issue is that simple statements like "discharge below 50% will significantly reduce battery life", or "it can be discharged below 50% with no damage", taken by themselves, don't tell the story, and lead to erroneous conclusions.


The fuller story is that LA battteries wear out based on the total number of Ah you run through them, not simply based on cycles. Why? Because a "cycle" can be down to 80% SOC and a small number of Ah, or down to 40% SOC and a larger number of Ah. Deep cycles run more Ah through the battery, so you get fewer of those cycles compared to a shallow cycle that consumes fewer Ah. There is no "cliff" at 50% discharge that cases cycle life to suddenly change from a big number to a small number. It's just the opposite. Cycle life is a continuum from shallow cycles to deep cycles, because what you are really "using up" are Ah, not cycles. This is what the lifecycle chart from FireFly is showing. But this takes a paragraph of dense info to explain, so insufficient for a Tweet. "Don't go below 50%" Tweets much better.



But the most probable killer of a LA battery is abuse, not actually wearing it out. That abuse comes in the form of sulfation which occurs when a battery is left at a partial state of charge for an extended period of time. The more you operate at lower SOC levels, the more opportunity there is for the naturally forming sulfate to harden, making it difficult to re-combine on a recharge cycle. Sulfate that can not be recombined through charging reduces the capacity of the battery. Fireflys are said to be much more resistant to sulfate hardening, so hanging out for longer at lower SOC will not result in hardened and lost sulfate, so no long term loss or damage to the battery. That's what the MarineHowTo statement is referring to.


So the FireFly chart and the MarineHowTo quote are talking about two different things, both of which are factors in battery life. It's not a question of one or the other, it's a question of which one gets you first.


Now, finally, your question....


One of the advantages of LFP is that it does not suffer from prolonged operation at lower SOC. You can basically operate up and down through the SOC range any way you want, and it's just fine. So they are not vulnerable the way LA (including FireFly).


That said, LFP can be abused in their own ways. Heat and cold reduces their life, but that's true for LA as well. Over charging or over discharging will kill an LFP quickly. The same is true for LA, and they are killed this way all the time. But it's not so sudden for LA, especially overcharging.


Like LA, LFP also just wear out over time, but it's a much longer time. There are dozens of research projects that have run LFP from 0% to 100% SOC, charging and discharging at the maximum allowed rate. Getting 2500 cycles like that is a no-brainer. I'm not aware of any actual long term tests for a more typical not-to-exceed 10% to 90% SOC (and usually less) cycling of a house bank with charge and discharge rates in the C/2 or lower range, simply because they would take so long. But predictions range from 3,000 to as many as 10,000 cycles under these conditions. We can check back in 10+ years to see.


One thing the Morgan's Cloud article points out that I also touched on a while back is that virtually all the test data and performance claims for FireFlys are from the manufacturer. There is almost nothing but anecdotal data from anyone else, and little to no independent research. Now I'm not trying to suggest any of the claims are wrong. I don't know one way or another. But unlike for FireFlys, there are scores and scores of independent research papers on LFP spanning 20+ years. It's very well understood, and very well proven.

 

[ksanders]

Kevin,

Charging times will be reduced on lithium because their charge acceptance rate is higher. That last 10 - 20 percent will go as quickly as the first 30 percent. Fire flys take a long time to get to 100 percent, and their charge acceptance rate is higher than that of standard AGM.

Gordon

Gordon

Yes LiFeP04 batteries have a higher charge acceptance rate. That said it is Extremely difficult and expensive to exceed the bulk charge rate of a trawler sized FLA bank. My bank of four L16 batteries is typical in size for a 50’ boat, and has a charge current acceptance of 200 amps. Few have a charger that can supply 200A Plus the normal house loads.

Yes the charge rate of FLA batteries reduces above 80% SOC or actually above 14.35 volts. Thats why those that understand FLA batteries do not run their generator past the bulk charging phase.

I’m not saying that LiFeP04 batteries do not have some advantages, but generator run time reduction is not one of them for most installed systems. Twistedtree in his post just above this one does an excellent job of explaining the advantages, and offers a great explanation of lifecycle issues.

My argument is also that many that tout their great success with LiFeP04 batteries are incorrectly attributing their new systems performance to the LifeP04 batteries. The reality is that these same people had a marginal charging system to begin with, and the batteries they chose are just part of their major charging system upgrade.

I would also argue that if they performed the exact same electrical system upgrade but chose any of the competing technologies for batteries their end results would be surprisingly similar.

 

[cardude01]

Twistedtree, thanks for that excellent explanation.

 

[Streff]

I have been itching to upgrade to Lithiums first in our RV and now on the boat. I was ready to pull the trigger on 3 x 200AH (or 3 x 150AH) last week but got concerned with the 3s max current draw capability of the Li batts. I have 48V Wesmar bow & stern thrusters that consume 490amps when in use. My current Fullrivers (3x260AH) house batteries also serve the thrusters and the windlass. I think max 3s current draw capability is another consideration.

My current AGM fullrivers 8Ds typically have plenty of max current draw but the Li can only support 120A for 3s (for the 150AH batt) or 150A (for the 200AH batt).. still below what is needed for the thrusters. I can create extra room for a 4th Li with some difficulty but doable.. more time than $.

Spoke with a Li manufacturer 2 days ago and they indicated that their newest batt can provide a much higher max amp draw thus satisfying the thrusters’ demand.
Current negotiated price fir the 150s is $1100 per or $1500 for the 200ah, when purchasing 3 batts.

My current Fullriver drop their voltage rather quickly with any decent draw but eventually recover. They are 4 years old. To replace them today, price is $875 per for a 260ah deep cycle if buying 3 units.

I am not looking forward to pulling these 180lbs monsters out of the engine room and even less installing another 3 heavies back in there. The convenience of the Lithiums is very attractive in that regard.

Streff

 

[Tator]

I'm a little confused how you get 48v from three 12 volt batteries wired in series.

If you consume 490ahrs using your thrusters( This would be 65% of your bank capacity and seems awfully high and I assume this is a 12v number), what is the maximum draw of the thrusters?

The specs on the Lion lithiums are 150 amp max continuous draw and over 150amp, for 50 seconds. I assume -perhaps wrongly- that if one had three 105 ahr Lions in parallel, they would be a 450 amp draw max at 12v and over the amount would be for 50 seconds.

There are other questions concerning you bank size if the 490ahr figure is correct.

Tator

 

[Streff]

Thank you for the comment, Tator. The 48V come from a DC-to-DC transformer, i also have a 24V Kabola heating system that is fed through a DCtoDC transformer.

The batteries are connected in parallel.. the thrusters pull 490amps (not amphrs) for the few seconds or so that they are working. So not much AHs in the big picture. But the bow thrusters alone need to pull 490amps to work properly for the short duration.

 

[sbman]

Thank you for the comment, Tator. The 48V come from a DC-to-DC transformer, i also have a 24V Kabola heating system that is fed through a DCtoDC transformer.

The batteries are connected in parallel.. the thrusters pull 490amps (not amphrs) for the few seconds or so that they are working. So not much AHs in the big picture. But the bow thrusters alone need to pull 490amps to work properly for the short duration.

I'm curious about the DC-DC transformer, I've not seen any that can boost voltage at those kinds of current levels. What kind is it?

 

[Streff]

One is a Siemens, cant remember the other but it’s from a Solar system outfit.