LiFePO4 vs FLA - The Real Deal

[ramblinrod]

Originally Posted by 44'cruisingcat

Certainly, if you search around for the mosr expensive lithiums you can buy, and compare them to the cheapest lead acid you can find, there's that argument.

But it's not realistic.

In my case, i looked for the best value for money AGMs I could find, and the best value lithiums.

The lithiums cost 50% more. (This is in Australia, apparently you can buy FLA batteries much cheaper in the USA. ).

So my lithiums have to last 9 years to break even financially. I fully expect them to go well beyond that. And in the meantime, they're simply better batteries.

Wait a minute?

Who wants to buy the "most expensive" things they can?

I have compared the "best value" FLA to the "best value" LiFePO4 I could find.

Just for the batteries, the LiFePO4 cost ~6 times as much. That doesn't include the shipping cost, from who knows where, to who knows where, when I can pick up initial and replacement FLAs anywhere.

On that basis, the LiFePO4s would have to last 30 years + just to break even. That's a ridiculous financial investment. Lucky if the LiFePO4s last 10.

Unless the goal is to spend more money than necessary.

If a bank of FLAs can meet all of the cruisers energy needs for 5 years for 1/6 the cost, how is it that LiFePO4s are better?

As we have seen from the direct comparison posted previously, A-hr for A-hr, the LiFePO4s were virtually identical in size, and half the weight. 150 pounds weight savings. So what?

I know some claim more usable capacity in LiFePO4s, so they can carry less, but that is a lark for 2 reasons.

Every cruiser needs at least 50% reserve capacity regardless of battery chemistry.

If one throws reserve capacity out the window for LiFePO4s, for a direct comparison, they must do same for FLA. If they do, they will reduce the life expectancy of the FLAs somewhat, but not nearly enough to financially justify LiFePO4s.

Claiming that attributes that aren't used or needed are "better" to justify 6 times the cost is ridiculous.

If you needed to lift 1000 lbs, and you could rent a 6000 lb capacity crane for $830 or a 10,000 lb capacity crane for $4750, which crane would you rent?

If you needed the thing lifted before the end of the day, and the "better" crane could lift it by noon, so what?

This is the kind of difference we are talking about.

[john61ct]

I 100% agree that you should not invest in the latest tech if you don't want to.

Few people need to.

Up to you, your rig your call.

Those who do, have their reasons, you may feel they're silly, wasting their money, but not anyone else's business.

Their rig their call.

This is not a religion either way, getting personally invested in "campaigning" one way or the other makes no sense.

To me.

[mbartosch]

Wait a minute. You are fine with LA batteries and don‘t see the need for LFP? Then just continue using LA, that simple.

In other news, 3 year old LiFePO4 install here. 400 Ah, 435 Wp solar, 120 A Balmar 6 alternator, no wind gen. Experience shows we need 120 Ah (@ 12V) at anchor and 250 - 300 Ah on the move. Self-sufficient (neutral to slight surplus)
energy balance when moored, 1.5 to 2 h of engine usage per day required on average when sailing on long passages (ocean crossing). Planning to add hydro gen to cover sailing gap for indeterminate sailing.
One year of full time cruising, zero shore power used.
Try this with a LA bank.

[ramblinrod]

Originally Posted by john61ct

I 100% agree that you should not invest in the latest tech if you don't want to.

Few people need to.

Up to you, your rig your call.

Those who do, have their reasons, you may feel they're silly, wasting their money, but not anyone else's business.

Their rig their call.

This is not a religion either way, getting personally invested in "campaigning" one way or the other makes no sense.

To me.

I just thought it was high time someone had the guts to counter all of the LiFePO4 "campaigning".

The purpose of the battery bank is to store energy to meet electrical demand.

Both technologies can easily meet this goal for almost every application.

IMHO, the real deal is that LiFePO4 gets one a weight reduction (that is pretty insignificant in the cruising world), and a severely lightened wallet.

All the rest is little more than marketing hype that doesn't make one bit of difference out there.

If all of the electrical devices aboard can be powered as needed, that is what counts; the batteries have done their job.

[mbartosch]

Originally Posted by ramblinrod

I just thought it was high time someone had the guts to counter all of the LiFePO4 "campaigning".

There is a bunch of people who are documenting their own LiFePO4 setups - and they are reporting on their daily usage here on the forum.
This is actually a good thing, because these designs are still rare and highly customized to the needs of their owners. It is actually interesting for me to see other solutions, there are really some design variations out there.

As others have mentioned, in contrast to commercial LFP solutions the LiFePO4 DIY installs require some engineering, for this reason it is beneficial to document one's setup so others can look how things can be done and learn from other designs. When I did our installation there was little detail information on how actual designs are implemented, so I decided to document my engineering solution for others to learn from.

This hardly campaigning, this is "Open Sourcing" engineering knowledge. If you don't like it, don't read it.

IMHO, the real deal is that LiFePO4 gets one a weight reduction (that is pretty insignificant in the cruising world), and a severely lightened wallet.

All the rest is little more than marketing hype that doesn't make one bit of difference out there.

Your opinion, but I consider your opinion wrong. I do have a LiFePO4 bank, you seemingly don't.

Put differently: would I do the conversion from LA to LiFePO4 again? Absolutely, without any hesitation and I would almost certainly not change a thing in my design.

[ramblinrod]

Originally Posted by mbartosch

Put differently: would I do the conversion from LA to LiFePO4 again? Absolutely, without any hesitation and I would almost certainly not change a thing in my design.

I understand some get a kick out of designing "elegant" solutions.

That's fine.

I am proud of the "practical" solutions I come up with every day.

What can your system do, that a suitable FLA bank couldn't, with respect to storing adequate energy in an economically justifiable way to operate the electrical devices aboard?

[a64pilot]

Originally Posted by daletournier

This is exactly my view. By the time my current batteries die Lifepo is mainstream and cheap, this dimishes the greatly the downside for ne.

A64, if you did go Lifepo how would your cruising day to day real life improve?

I wouldn’t worry about recharging, I’d only be concerned if I had enough to get by tonight.
I’d still be running my generator though, to make water and wash clothes, but maybe not as much. So there would be improvement, enough to justify thousands of $$$? Likely not, it all depends on how much money you have to spend, and how much you want to have the latest, greatest thing.
Cause for me the weight difference is likely irrelevant. Sure it would help some, but I carry 1,300 lbs if water, in truth she sails about the same tank full or tank empty, and I don’t have 1300 lbs of batteries. I think about 350 lbs. (660 AH) the weight of one fat guy, just isn’t going to matter.

[CatNewBee]

Originally Posted by a64pilot

I wouldn’t worry about recharging, I’d only be concerned if I had enough to get by tonight.
I’d still be running my generator though, to make water and wash clothes, but maybe not as much. So there would be improvement, enough to justify thousands of $$$? Likely not, it all depends on how much money you have to spend, and how much you want to have the latest, greatest thing.
Cause for me the weight difference is likely irrelevant. Sure it would help some, but I carry 1,300 lbs if water, in truth she sails about the same tank full or tank empty, and I don’t have 1300 lbs of batteries. I think about 350 lbs. (660 AH) the weight of one fat guy, just isn’t going to matter.

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!

[daletournier]

Originally Posted by mbartosch

Wait a minute. You are fine with LA batteries and don‘t see the need for LFP? Then just continue using LA, that simple.

In other news, 3 year old LiFePO4 install here. 400 Ah, 435 Wp solar, 120 A Balmar 6 alternator, no wind gen. Experience shows we need 120 Ah (@ 12V) at anchor and 250 - 300 Ah on the move. Self-sufficient (neutral to slight surplus)
energy balance when moored, 1.5 to 2 h of engine usage per day required on average when sailing on long passages (ocean crossing). Planning to add hydro gen to cover sailing gap for indeterminate sailing.
One year of full time cruising, zero shore power used.
Try this with a LA bank.

I agree with John, there's no right and wrong here, just choices, BUT I don't get your "try this with Fla" comment ? Do you mean not hooking up to shore power in a year? I never hook up to shore power, in fact I haven't had much shore power to hook upto for going on 9 years.

Ive just come back from dinner aboard a cat with 1,400ah Lifepo batteries, music was playing, lights were on, guess what, I'm back on my boat, lights are on, musics playing. I'm fairly certain my electricity is as good as Eric's, and visa versa.

[CountyChick]

Hello!

I don't own a boat, but I've been lurking here for a few weeks because I'm building a small off-grid house. Some of the info on this forum is interesting to me because managing energy in an off-grid house is similar in some ways to managing energy on a boat.

I've been living full-time in my off-grid house for two years. I've been relying on a small, kludgy solar-electric system during that time, but I'm about to build a bigger and better solar-electric system. After tons of research, I've decided to use four SimpliPhi 3.5kWH 48V LiFePO4 batteries for the battery bank in my new system. These are my reasons:

- You can do 80% DOD without damaging the batteries. Note that I don't expect to go to that DOD routinely, as I'll have a 14kWH battery bank, and my house, when finished, will probably use only about 2.5kWH per day. But it's nice to know I can drop down to 80% DOD if we have several continguous days without much sunshine. And I do have a gas generator, so I never even have to get anywhere near 80% DOD if I don't want to.

- My LiFePO4 battery bank will occupy less space than a battery bank of the same capacity that's made of lead-acid batteries. Conserving space is important to me because my house is small.

- LiFePO4 batteries don't require venting. I didn't want to get involved in building a venting system, nor did I want to provide power to a venting system.

- LiFePO4 batteries don't require maintenance - so no checking the specific gravity, adding distilled water, exposing myself to potential explosions.

- LiFePO4 batteries tolerate cold better than lead-acid batteries. This is important in my particular situation because my battery bank will be located in an area of my basement that sometimes gets as cold as 40 degrees F.

My new system will probably be up and running within a couple months. I'll circle back here after it's been in use for awhile.

[zboss]

It seems to me that the ability to charge at bulk for almost the entire charging cycle is a bigger deal to some than others. There are many days where we only get maybe 1 or 2 hours of useful sunlight and no useful wind. I suspect that if we had lithiums we could count on those batteries regaining much more of their charge in those two hours vs. our firefly batteries (although we already charge much much faster than our old FLA).

On those days we are generally forced to start the generator and since we have the generator on, we tend to want to get as close to topping out the batteries as we can. This can mean running our generator longer than I can stand it sometimes. Our 70 amp charger is sufficiently sized because the AGMs can't take that full 70A for long.

If we had lithiums, we could upscale the charger to 100 amp (or as much as our Honda genny could take) and it would charge the batteries much much faster, cutting down on fuel and giving us more time to enjoy swimming, boarding, and snorkeling. I estimate it would cut our charge time in half. So instead of bothering everyone in the anchorage for 2 or 3 hours we could just run it for an hour.

We could probably even get rid of our wind generator.

I think your napkin scenario math is off a bit. You would need 1/2 as many lithium batteries as you counted, could drop the wind generator altogether, and cut the generator runtime by probably 1/4. You also didn't count the cost of mounting 1000 watts of solar vs. the cost of 600.

[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

[ramblinrod]

Originally Posted by zboss

It seems to me that the ability to charge at bulk for almost the entire charging cycle is a bigger deal to some than others. There are many days where we only get maybe 1 or 2 hours of useful sunlight and no useful wind. I suspect that if we had lithiums we could count on those batteries regaining much more of their charge in those two hours vs. our firefly batteries (although we already charge much much faster than our old FLA).

On those days we are generally forced to start the generator and since we have the generator on, we tend to want to get as close to topping out the batteries as we can. This can mean running our generator longer than I can stand it sometimes. Our 70 amp charger is sufficiently sized because the AGMs can't take that full 70A for long.

If we had lithiums, we could upscale the charger to 100 amp (or as much as our Honda genny could take) and it would charge the batteries much much faster, cutting down on fuel and giving us more time to enjoy swimming, boarding, and snorkeling. I estimate it would cut our charge time in half. So instead of bothering everyone in the anchorage for 2 or 3 hours we could just run it for an hour.

We could probably even get rid of our wind generator.

I think your napkin scenario math is off a bit. You would need 1/2 as many lithium batteries as you counted, could drop the wind generator altogether, and cut the generator runtime by probably 1/4. You also didn't count the cost of mounting 1000 watts of solar vs. the cost of 600.

Nor did I count the cost for LifePO4 for mounting the generator to make use of the fast charging rate. Tit for tat.

Everyone keeps saying they only need half the LifePO4 capacity, but as I have stated, this simply isn't true.

The LifePO4 battery exampled I posted, has virtually the same volume for the same Amp-hrs as a cheap FLA.

Everyone tells me LifePO4 can be discharged to use 80% of the total capacity.

So can FLA.

But regardless of which battery technology, one should design for at least 50% reserve capacity, so they don't have to start the genny every day there is a cloud in the sky.

Any boat battery system designed with no reserve capacity is simply bad design, IMHO.

FLA should charge about as fast as a reasonable solar and wind charging system can deliver, up to about 75%. The last 25% slow down, a little at first and more the closer to 100%.

If it takes all day to get to 100%, so what?

On a sunny or windy day, the charging system will bring it up to 100%.

On a cloudy or calm day, maybe less, but as long as it is sunny or windy in the next few days, it will be brought back up from maybe 80% to 100%.

All is good.

On any occasion where wind and solar aren't likely to cut it, and I'm down ot 50% or less, (rare) I just start the engine in the morning when charge is lowest, bring the batteries up to 75% (using everything the alternator can deliver) and let what ever wind or solar there is fill them up as much as it can. If we can produce just about anything, they will be at 12.8Vdc (fully charged) an hour after sunset (and the loads have depleted the residual charge voltage).

As far as I can tell, FLA batteries simply aren't the problem that LifePO4 proponents claim they are.

[44'cruisingcat]

I know some claim more usable capacity in LiFePO4s, so they can carry less, but that is a lark for 2 reasons.

Every cruiser needs at least 50% reserve capacity regardless of battery chemistry.

[/QUOTE]

50% of what?

If you have 1000 amp hours of lead you can use about 400 of it and expect 1500 cycles.

With 600 ah of llithium you can use about 500. And expect 3000 cycles.

[Jammer]

Interesting premise for a thread.

Originally Posted by ramblinrod

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?

For lifepo4 you'll get around 10 kwh per cubic foot and 175 wh per kg, according to proponents of the technology. For FLAs, using the Trojan L16 as a benchmark, you'll get 2.5 kwh per cubic foot and 40 wh per kg. 4x difference. I don't know if I believe that or not. I would be inclined to believe that there is at least a 2x difference in energy density, however.


Whether this is a big deal depends on the situation. There are situations where it is a very big deal because there just isn't enough space or weight carrying capacity to bring a sufficient amount of FLA battery.