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Old 24-08-2018, 17:57   #76
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Re: LiFePO4 vs FLA - The Real Deal

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Originally Posted by ramblinrod View Post
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.


I feel you have an overly optimistic view of FLA and the associated charging requirements if you run them down past 50% on a regular basis, especially if you believe you can effectively run them down to 20% on a nightly basis without having them fail on you at the very worst time.

If your electrical requirements are very minimal than you can get by with FLA but today’s boat is packed with energy hogs.

All my charging equipment is fully programmable within an hour or so and I’m able to make use of any battery type I might come across worldwide, as long as I can find it in a standard size. That is probably worth more than holding to a single type of battery based on principle.
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Old 24-08-2018, 20:53   #77
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Re: LiFePO4 vs FLA - The Real Deal

[QUOTE=zboss;2704300]
Quote:
I feel you have an overly optimistic view of FLA and the associated charging requirements if you run them down past 50% on a regular basis, especially if you believe you can effectively run them down to 20% on a nightly basis without having them fail on you at the very worst time.
I have never stated this, not once.

I have stated that regardless of battery technology, one should plan for about 50% reserve capacity.

Before wind and solar, the general recommendation was to plan a charge cycle for FLAs from 85%-50% as it took too much generator run time to charge to 100%.

This proved to be hard on batteries if they were rarely brought up to 100%.

Now with wind and especially solar being so affordable, charging FLAs to 100% almost every day is easy.

If on "occasion" one dips down to 20%, as long as they are recharged to 100% soon, the batteries aren't hurt significantly. 1 or 2 such incidences per month may take maybe a week off their 5 +/- 1 year life expectancy.

Even though a LifePO4 can be discharged to 20% regularly with no ill effect, if the system is designed properly with sufficient reserve capacity they will typically only be discharged to 50% on average, the same as FLA.

Quote:
If your electrical requirements are very minimal than you can get by with FLA but today’s boat is packed with energy hogs.
LifePo4s have only been on the scene a few years. Boats have had electrical needs for a long time.

Again, the energy density of LiFePO4s isn't actually what it is often cracked up to be, as evidenced by the models posted earlier that have pretty much exact dimensions and A-hr capacity of a FLA Grp 31.

Quote:
All my charging equipment is fully programmable within an hour or so and I’m able to make use of any battery type I might come across worldwide, as long as I can find it in a standard size. That is probably worth more than holding to a single type of battery based on principle.
So if you lose 1 LiFePO4 you will trash all what quantity of expensive batteries so you can put in what other chemistry?

Is that a wise choice for a long distance cruiser?

Why not just design the electrical system around a battery technology that is available inexpensively pretty much any where in the world?
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Old 24-08-2018, 21:03   #78
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Re: LiFePO4 vs FLA - The Real Deal

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Originally Posted by ramblinrod View Post

Even though a LifePO4 can be discharged to 20% regularly with no ill effect, if the system is designed properly with sufficient reserve capacity they will typically only be discharged to 50% on average, the same as FLA.
And if you only cycle down to 50% you can expect 10,000 + cycles. Basically, you'll never need batteries again.
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Old 24-08-2018, 21:05   #79
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Re: LiFePO4 vs FLA - The Real Deal

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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.
This is only true, because you are comparing LifePO4s to fairly expensive AGMs.

Change the comparison to standard FLA deep cycles, like the Grp 31s I used for the example I posted and your LifePO4's were likely around 8 times the cost.

Justify that financially when the affordable Grp31s treated properly will last 5+ years when full time cruising. There is not a hope in the hot place that your LiFePO4s will last 40+ years.


Your argument is like saying a Lamborghini is not an expensive vehicle, because they are only a little more expensive than a Ferrari.

But compared to a Porsche Boxster they are both ridiculously expensive.
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Old 24-08-2018, 21:09   #80
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Re: LiFePO4 vs FLA - The Real Deal

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And if you only cycle down to 50% you can expect maybe 10,000 cycles. Basically, you'll never need batteries again.
Smirk. Yeah right.
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Old 24-08-2018, 21:27   #81
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Re: LiFePO4 vs FLA - The Real Deal

Yes really.

Note that outside the US market, especially in the southern hemisphere, good quality FLA are by no means cheap.

AGM is also very expensive, and rarely what we would call good quality for deep cycling.

And LFP not just cheaper, but a more mature distribution system.

Therefore as some have tried to make clear, when LFP is only 30-50% cheaper than lead, and much more widely implemented, including the "caravan" market, that changes the situation a lot.

Getting great deep cycle FLA batts for $1/AH is only available in the NA market.
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Old 24-08-2018, 21:30   #82
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Re: LiFePO4 vs FLA - The Real Deal

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Originally Posted by ramblinrod View Post
This is only true, because you are comparing LifePO4s to fairly expensive AGMs.

Change the comparison to standard FLA deep cycles, like the Grp 31s I used for the example I posted and your LifePO4's were likely around 8 times the cost.

Justify that financially when the affordable Grp31s treated properly will last 5+ years when full time cruising. There is not a hope in the hot place that your LiFePO4s will last 40+ years.


Your argument is like saying a Lamborghini is not an expensive vehicle, because they are only a little more expensive than a Ferrari.

But compared to a Porsche Boxster they are both ridiculously expensive.
actually rod my 200ah of Lfp only cost 2.50 per ah so only double the cost of Fla also not much above the cost of agm . However with only discharging to 50% I will get at a minimum 6k cycles so in the long run they are cheaper ah for ah over the lifetime of re batteries.
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Old 24-08-2018, 21:33   #83
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Re: LiFePO4 vs FLA - The Real Deal

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Originally Posted by ramblinrod View Post
This is only true, because you are comparing LifePO4s to fairly expensive AGMs.

Change the comparison to standard FLA deep cycles, like the Grp 31s I used for the example I posted and your LifePO4's were likely around 8 times the cost.

.
Nope. In Australia, decent deep cycle FLAs were actually more expensive than AGMs. Possibly due to the country of manufacture.

The fact is, I spent weeks looking into this. Originally I wasn't keen on going lithium. It seemed like they were too delicate, needed too much looking after.

Research showed this simply wasn't the case. And later incidents demonstrated the reverse.

2 instances of batteries that have been run dead flat, left for months, then recovered. Try that with lead.

Batteries left in a shed for 7 years, with no maintenance, no charging. Still at 13.1 volts.
Try that with lead.

No matter how much you may hate it, the fact is, lithiums are the future. Lead will soon be dead. Get used to it.
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Old 24-08-2018, 22:09   #84
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Re: LiFePO4 vs FLA - The Real Deal

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actually rod my 200ah of Lfp only cost 2.50 per ah so only double the cost of Fla also not much above the cost of agm . However with only discharging to 50% I will get at a minimum 6k cycles so in the long run they are cheaper ah for ah over the lifetime of re batteries.
You can get a brand new 100 A-hr LifePO4 with built in BMS for only $250.

Please advise, I will by 4 tomorrow.
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Old 24-08-2018, 22:16   #85
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Re: LiFePO4 vs FLA - The Real Deal

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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.


Your funny, the most strangest way of comparing things.
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Old 24-08-2018, 22:19   #86
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Re: LiFePO4 vs FLA - The Real Deal

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You can get a brand new 100 A-hr LifePO4 with built in BMS for only $250.

Please advise, I will by 4 tomorrow.
actually it was 248.00 delivered. I'm still testing look for the Lipo vs lifepo4 for more info and testing data to date
http://www.cruisersforum.com/forums/...o4-194142.html
The last few pages are the relevant ones.
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Old 24-08-2018, 22:25   #87
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Re: LiFePO4 vs FLA - The Real Deal

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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.
Didn't take long for you to forget your manners, well done.
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Old 24-08-2018, 22:32   #88
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Re: LiFePO4 vs FLA - The Real Deal

You cant be serious...
There is no 50% reserve capacity in a FLA. You can only use maximum 50% of the nominal capacity without causing serious damage. And the many cycles come from 30% discharge, not 50 or 80.

Of course you can abuse your FLA, the dealer around the corner is waiting for you.

Also high current draws kill FLA on the long run. Continous discharge is around 0.1...0.2C.

A FLA battery with 1000Ah can safely continous deliver 100...200A, a a LFP can deliver 1000A. This is a very strong argument for all who use regulary powerfull inverters. The voltage drop of a FLA battery would require much higher capacity to cope with the currents.
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Old 24-08-2018, 22:37   #89
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Re: LiFePO4 vs FLA - The Real Deal

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You cant be serious...
There is no 50% reserve capacity in a FLA. You can only use maximum 50% of the nominal capacity without causing serious damage. And the many cycles come from 30% discharge, not 50 or 80.

Of course you can abuse your FLA, the dealer around the corner is waiting for you.

Also high current draws kill FLA on the long run. Continous discharge is around 0.1...0.2C.

A FLA battery with 1000Ah can safely continous deliver 100...200A, a a LFP can deliver 1000A. This is a very strong argument for all who use regulary powerfull inverters. The voltage drop of a FLA battery would require much higher capacity to cope with the currents.
actually there is a very good discussion on that exact subject.
http://www.cruisersforum.com/forums/...th-206151.html
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Old 24-08-2018, 22:46   #90
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Re: LiFePO4 vs FLA - The Real Deal

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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.
For the record I was actually trying to say I understand performance cat owners much preferring Lfp due to the desire to be lighter, as is the topic of another thread running. I didn't say you can't carry a bigger bank, I didn't say your boat would sink if you did,
I was saying you probably don't want to carry 900ah (which i have) , being a performance cruising cat owner. This was not intended as an insult to you or your boat, which I like alot BTW.

In regards to typing c44, it was a typo, sorry about that, in regards to your aggression, it's real easy behind a keyboard and it's cowardly. Feel free to put me on an ignore list or just ignore my posts if they cause you issues. If you do respond then great, your a knowledgeable bloke, and I read what you say with interest but please don't be rude. People are entitled to view the world differently to you.

Also most here including me didn't buy our batteries in Australia. Most have found up to date Lfp to be much more expensive than wet cell trojans such as I use.
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