LiFePO4 vs FLA - The Real Deal

[Simi 60]

Originally Posted by CatNewBee

Nobody says, you should go for LFP.

I did it, and I like it!
Its like shore power on the boat. I had 480Ah Equipment GEL, usable cap 240Ah, than the alarm sounds. In the same compartment I now have 1000Ah, usable 1000Ah! Can discharge 1200Ah from full to empty, because the cells are overprovisioned for warranty reason.

Guess what, my solar is mostly the only charge source, fridges, freezers, induction cooktop, oven, ice maker, A/C, watermaker, espresso machine, washing machine.... everything on board runs from the battery now, no more generator time.

Thats true, the conversion costs me 15k, the battery was 5k, the rest is solar, inverter and galley upgrades.

I do not even think about energy or shore power in the marina and I can leave off-grid as long as I have food. Have I mentioned 0 (zero) generator time!

Sounds impressive but is it anything overly special?
We have been living at anchor for over two years running 750 litres/26cf of 240v fridge freezer, rheem 240v hot water system, washing machine, etc etc with no power concerns.
Like you, solar is mostly our only charge source.
In winter and rainy days we need some genset, if there is some sun an hour does it.

Power comes from our $3000 worth of agm batts (8x220ah @ 12)
$1200 worth of tier 1 panels (9 x 250w)
$800 midnite mppt
And a $3000 victron 5000va/100a inverter charger.


Thats $8k worth.

Don't get me wrong I'm impressed by lp4 numbers and I'll be looking at lp4 batts at replacement time, hopefully by then they'll be considerably cheaper.

[44'cruisingcat]

I have to say, if lithiums were 5 or 6 times the price of AGMs, we'd still have AGMs on our boat.

But here in Aus, the difference is nothing like that.

For equal usable amps, lithiums cost about 50% more. Which means they only need to last 50% longer for all the other benefits to be free.

[newhaul]

Originally Posted by ramblinrod

Hi All,

I have a fair bit of experience with FLA batteries and am trying to figure out what all the hype is about over LiFePO4.

What I have heard so far about LiFePO4 is:

Pros:

Higher energy density. How much? For a given dimension of battery case, lets say equal to a FLA Grp 27 100 A-hr battery, how many more A-hrs capacity does a LiFePO4 have?

Higher Usable Capacity. I hear people tout 80% (charge cycle from 90 - 10%).

Wait a mintute!

Shouldn't we design for 50% reserve capacity?

What if there is no sun or wind one day?

What if the girlfriends hair gets longer and she needs to run the blow drier another 5 minutes per day?

So if we design for 50% reserve capacity of 80% max capacity (so we don't hurt the battery), we're talking cycling the battery from 90-50%.

Wait a minute!

We were cycling our FLAs from 100-50%, and if on occasion we had to dip into the reserve, say to 20%, no biggy as long as we charged right back up again.

We could have design for 100% - 20% charge cycle on our FLAs too. They probably wouldn't last as long, but isn't that a fair weight/capacity trade-off?

Faster Charging: Sure, pound the Amps into that puppy.

Wait a minute!

Where are they going to come from?

The 400W wind genny and the 400 W solar panels will only deliver a high of about 30 A max.

So we are going to be forced to run ICE (Internal Combustion Engine) to gain any benefit of the fast charging capability.

Isn't the goal for most cruisers to avoid running the ICE when it isn't necessary?

Reduced Voltage Sag.

The output remains constant right down to 10% DOD.

Wait a minute!

Voltage sag is never really a problem when using a properly sized FLA bank.

So it seems the only time LifePO4 would really be a benefit if one is going to throw on a thruster, windlass, or huge inverter with heavy load, when the FLA bank is really low.

Is that the only real benefit?

CONS:

Expensive. By the time the batteries are purchased, higher output shore power and ICE charging is included. This "upgrade" will be many thousands of dollars.

Wait a minute!

Wouldn't it be a lot more economical to just use a smaller bank of FLAs with design charge cycle of 100-20%, and replace them more often?

Limited Availability. There are only a few suppliers with limited distribution channels with very limited (if any) stock at the retail level.

Wait a minute!

One can get a replacement FLA battery anywhere.

Consequence of Failure:

If something goes wrong, like the batteries get trashed by an incorrect charge or discharge incident, how much will it cost and how long will it take?

OK, I think that about sums up my thoughts.

To me, the only real benefit I see to switching from FLA to LifePO4 is the ability to say, "I have LiFePO4s".

Am I missing something?

you don't like Lfp we get it so just move along.
Btw your figures are way off on solar and wind.

I routinely see 27 amps out of my 400 watts solar for multiple hours A day.
Now I do only get an average of 15 amps out of my 400 watt wind generator but that's averaged over 24 hours ( when the wind blows )
now lets do some math I will end up with 300ah Lfp so 20 amps solar x 3 hours a day ( more like 5 but) that is 60ah a day. ( I get an average of 75 ah a day summer)
now 15 amps wind x 24 hours= 360ah potential. So in closing I have a potential ( verifiable) 435ah per day ( I know I won't get that much every day . However I do get enough to cover my power usage by about the power of 5 daily.. Now throw a 105 amp stock small frame alternator and if needed ( doubt I would ever need it) about 60-70ah charging potential. ( also about double my expected daily usage)
where does the need for a generator come in.

[thinwater]

I thought that was a great opening post! They are intended to open dialog, and he laid it right out there in a straight line.

Obviously there are counterarguments. However, most boaters place a very low premium on weight (and in the bilge of a mono it's a minor thing). PSOC life reduction is just part of the math. Cycles only matter if you cruise full time and spend most nights on the hook (weekend cruiser batteries die of old age). So the bottom line to me is you either need unusual cost/benefit levers (carbon fiber boat) or you just want "the best," in which case, go for it.

For me (weekend cruiser now days, performance boat), the best cost/benefit answer is LA with relatively deep discharge when I need it, recharge ASAP, and replace as needed. Nothing fancy helps.

[44'cruisingcat]

Originally Posted by thinwater

Cycles only matter if you cruise full time and spend most nights on the hook.

Some of us actually do this.

[newhaul]

Originally Posted by 44'cruisingcat

Some of us actually do this.

amen and more of us than most people think.

[thinwater]

Temperature vs. voltage. Someone commented they handled cold differently.



The data I have (several sources) shows that both LA and Li drop about 4% from 70F to 32F. Data?

[thinwater]

Originally Posted by 44'cruisingcat

Some of us actually do this.

And some of us like living in houses. They are simply represent different usage patterns. My pattern means little to you, and your pattern means nothing to the 99% of sailors that do not cruise full time. I respect your experience, and there are quite a few of you, but still a tiny, tiny part of the boating market. You have one set of maths on this, the rest have a different set. And cats are different from monos, most of whom don't care about weight in the bilge.

[CapnBazza]

You’re not missing anything Rod, there are people who still don’t have a mobile phone and they too seem to survive. Don’t worry about it mate, stick with your fla batteries. Personally, I like waking up with 13.2 volts. But I even have an ipad.

[senormechanico]

I'm laughing at some of the FLA responses.
For example:

"Ever had to sail without a generator?" LOL I never have owned one, and have been sailing with solar since 1992.
If I remember correctly, I've owned Lithiums on the boat since 2012.
The last time I carried a shore power cord was 2006 or so, and our boat has all the toys.

Standard equipment includes a full size Vitamix for smoothies and a 1650 watt hair dryer for my wife.
Spectra, Radar, electric flush toilet, ElectroScan treatment system, hot water from the inverter from the solar.
Try that with lead and no generator!


We don't cruise all year long, but if we did, it wouldn't be in the Pacific NorthWET.

[daletournier]

Originally Posted by CapnBazza

You’re not missing anything Rod, there are people who still don’t have a mobile phone and they too seem to survive. Don’t worry about it mate, stick with your fla batteries. Personally, I like waking up with 13.2 volts. But I even have an ipad.

I wake up every morning to 12.6v, you wake upto 13.2v, how does this make any real world difference? If you woke up to to 13.4v would you be happier again?

Everything on my boat works perfectly fine at 12.6v, as designed to.

I think many here are missing the point some of us are trying to make, the better performance of LFP you speak of is nice BUT dosent or wouldn't make any difference to our cruising lives as our current systems are designed and operating in away that easily meets our needs. I'm not sure why this is hard to understand. My electricity ususage quota of approximately 140-150ah on a full time liveaboard is comfortably and easily met year round from my fla batteries and charging system.

Rods crane scenario has merit, the bigger crane is better but isn't always nessacary, the job gets done anyway.

[daletournier]

Originally Posted by senormechanico

I'm laughing at some of the FLA responses.
For example:

"Ever had to sail without a generator?" LOL I never have owned one, and have been sailing with solar since 1992.
If I remember correctly, I've owned Lithiums on the boat since 2012.
The last time I carried a shore power cord was 2006 or so, and our boat has all the toys.

Standard equipment includes a full size Vitamix for smoothies and a 1650 watt hair dryer for my wife.
Spectra, Radar, electric flush toilet, ElectroScan treatment system, hot water from the inverter from the solar.
Try that with lead and no generator!


We don't cruise all year long, but if we did, it wouldn't be in the Pacific NorthWET.

Other than the hair dryer we do all of the above, so yer I do try it with a fla system, and successfully. I do carry a Honda 2kva as Cc44 carries a small Honda BUT it seldom gets used for battery charging as he states his dosent either.

You laugh at some of the Fla responses why? Is it so hard to understand that some of us have good very functional Fla systems that work day in day out with very minimal fuss? I top water up once a mth, that is the only fuss, nothing I'd call a problem.

How much better is your life than mine based on your battery setup? Maybe your previous systems prior LFP were inadequate for your needs thus the big improvement you have now.

In case your wondering, I'm not a power nazi, I use electricity in a comfortable way not much different to if I was living on shore, in fact not quite sure what I'd to differently. Do you think I live primitivly and are a slave to my batteries? Is it possible that changing to LFP may make very little difference to my lifestyle?

I'll use c44 as an example, I fully understand why he does not want 900ah of lead on his boat, different boat to me. In reality I use one bank of 675ah (225 ah second bank) to meet my needs, I easily carry this, it makes really no difference from a space perspective whether I carry 400ah or 675ah as I have the room, I accept I need greater capacity than you LFP guys to meet my needs which is a zero problem to my scenario, my battery boxes were designed to carry what I do.

[daletournier]

Sorry correction, I don't use the inverter to make hot water and acknowledge this would be nice.

[44'cruisingcat]

Originally Posted by daletournier

I'll use c44 as an example, I fully understand why he does not want 900ah of lead on his boat, different boat to me. In reality I use one bank of 675ah (225 ah second bank) to meet my needs, I easily carry this, it makes really no difference from a space perspective whether I carry 400ah or 675ah as I have the room, I accept I need greater capacity than you LFP guys to meet my needs which is a zero problem to my scenario, my battery boxes were designed to carry what I do.

If you're going to use me as an example, do it properly.

I had no problem carrying 600 ah of lead. And it did the job adequately.

How many times do I need to say this? I bought lithiums because they will almost certainly work out CHEAPER.

They only need to outlive the lead acid by 3 years, then financially I'm in front.

All the other stuff is gravy.

[CountyChick]

Originally Posted by JOHNMARDALL

Don't worry about this stuff. I'm working on a system that will draw energy from the quantum vacuum in unlimited quantities. The device is about the size of a boiled egg and will be able to propel an abandoned ferro-concrete sailboat at around light speed. Working on the details of my gofundme site - back soon.
Stand by (wait a minute)
John Mardall

JOHNMARDALL, I'm so glad you are working on this! I guess I'll hold off on building my new LiFePO4 system until you bring your spiffy new technology to market!