LiFePO4 vs FLA - The Real Deal

[thinwater]

Originally Posted by 44'cruisingcat

You could disconnect the batteries from the charging system during the off season.

I don't recognize an "off season."


If the boat is in the water they better not be unplugged (sump pump). Yes, it goes sub-freezing even with the boat in the water--I've frozen bottles.


Additionally, I'm not sure the vendors make this point clear.


---


I just want to know if winter sailing is a problem. I'm sure it is not of interest to very many. Is there experience? How do you store in-water in the winter in clod climates?


I have a call in to one manufacturer... but no word yet.

[john61ct]

Originally Posted by newhaul

there is one important part when leaving Lfp unused and "shelved" for extended periods they prefer to be at a partial charge in the 50% vicinity for the best longevity. FWIW

Nope. Now the word is

"as low SoC as possible"

which of course means ensuring that the self-discharge rate would never drop voltage below your chosen 0% SoC usage point

which will depend on temperature (cold is better) and the frequency of the bank getting checked on and given a boost when needed.

50% should be fine for say one year in cool ambient, but not optimal for longevity.

[44'cruisingcat]

Originally Posted by thinwater

I don't recognize an "off season."


.

And yet you said:

Originally Posted by thinwater

...... I'd bet half the boats see subfreezing temps for months and most probably leave the batteries on solar chargers in the off season, which will charge automatically whenever they see fit.

Which is why I referred to an off season.

[newhaul]

Originally Posted by john61ct

Nope. Now the word is

"as low SoC as possible"

which of course means ensuring that the self-discharge rate would never drop voltage below your chosen 0% SoC usage point

which will depend on temperature (cold is better) and the frequency of the bank getting checked on and given a boost when needed.

50% should be fine for say one year in cool ambient, but not optimal for longevity.

I stand kinda corrected.
I was implying the simple " off season" that most would agree is between 4 and 6 months depending on area. By leaving the vessel with 50% it allows for the discharges caused by odd day that they want to be at their vessel or the bilge pump runs during that time so as to not to not trigger the lvc.
.

[ramblinrod]

Originally Posted by 44'cruisingcat

Well you're wrong.

The fact is many cruisers DO stay away from marinas for long periods. Maybe not in the lake where you sail, but there's a whole world out there.

Define many?

As a percentage of all cruising sailboat owners, I believe it would be relatively few, who are away from the dock more than 6 days out of seven, for 6 months or more.

[john61ct]

But a very high percentage of those that should consider LFP.

Most boats have no battery other than starter at all.

[newhaul]

Originally Posted by ramblinrod

Define many?

As a percentage of all cruising sailboat owners, I believe it would be relatively few, who are away from the dock more than 6 days out of seven, for 6 months or more.

and for actual cruiser sailboat owners you would be incorrect.
There is a reason for watermaker sales being what they are as with tender usages .
Why do you think we carry a dingy and small outboard?
It sure ain't to look good.

[ramblinrod]

Originally Posted by newhaul

this contradicts your own statements concerning using the iron wind to do an 80% capacity recharge then allow solar to top it off .

The battery tech has a lot to do with acceptance rates .
You recommended 200 watts solar 200 watts wind and an 80 amp alternator per 100ah of battery.
With Lfp I can effectively remove the iron wind from the equation for my sailboat customers.
With power boat customers I would rather not install Lfp unless they are insistent .

I believe you are mistaken.

With a properly designed charging system wind and solar will provide a surplus
of charge capacity, for an average daily load, and an average wind and sun day.

The bank will be at 100%, at least once in the day.

On days with insufficient wind and sun to meet loads, they will be using battery stored capacity.

If your systems are designed with no reserve capacity, (100 A-hr bank for 100 A-hr average daily demand, if the demand is 50% higher than an average day, and there is no wind and sun, you will be using the ICE charging system in 13 hours, or sitting in the dark.

[ramblinrod]

Originally Posted by CatNewBee

I agree, LFP is not for everybody.
It is an elite system, that stands out in any matter, it is like a Porsche compared to a VW Beetle, It is fast, adorable, outperforms the Beetle on any race track and trafic light, it is engineered to maximize stability on the road, curve the race track and bring the kids to school.

The Beetle is designed to be cheap and easy to maintain, many people are happy with it. Thats OK, I like the Porsche and do value the extra power and enigineering ingenuity. Dont get me wrong, this are just contrary design goals, both are very successfull designs.

Anyway, for a flower power greenie, there is nothing that compares to a rusty hand painted VW Beetle, and they are religious about it. They would never understand the difference thet a Porsche makes, even it is a evolution product by the same designer, Ferdinand Porsche.

Dude, we are talking about batteries.

[Uncle Bob]

Contributors one and all, thanks for an educational update touching on all the relevant aspects of LiFePO4 battery situation. I personally believe that they are rapidly coming of age and the reported price comparisons are demonstrating a greater acceptance by many if not all . With my LA bank approaching probable half life it has given much food for thought.
Anyhow thanks for the info and spirited debate.

BTW, I believe that there are now glasses available without blinkers attached.

[senormechanico]

Originally Posted by evm1024

Hey Rod, Thanks for the timely reply.

Let me see if I can summarize it.

*- You have significant experience with part-time cruisers on Lake Ontario and an unknown number of world cruisers.

*- You have not seen a case where you thought LiFePO4 was an economically justifiable solution but you do know that such cases exist, and will recommend LiFePO4 in those cases.

*- You have not installed or worked on any LiFePO4 systems at this time.

*- Your opinion of the LiFePO4/FLA cost - benifit trade offs is based on significant experience with FLA and no direct experience with LiFePO4. Your opinion of LiFePO4 is formed from your research and reading on the subject.





Based on the above quote it appears that you think that LiFePO4 is not efficient or affordable. That only con man salesmen recommend LiFePO4 systems. That people who sell LiFePO4 solutions are making a boat load of money at their customers expence. And that owners who choose to install LiFePO4 systems are motivated to be cool in the eyes of other boaters.

OK, Fair enough. It is good to know where you are coming from.

Regards

I was going to post the same thing, but you beat me to it.

[senormechanico]

ramblinrod,



Sell all your stock in the obvious holdings in lead acid battery production.
Is it in lead mines or where?