Alternator Size with LiFePo4

[Q Xopa]

Originally Posted by kmacdonald

IMHO we are looking to use the wrong lithium battery chemistry. LiFePO4 won't make it through the sieve. Their properties vary too much from battery to battery and don't have the energy density of other chemistries. We will end up having to adopt whatever chemistry the EV car industry uses even though they may not be optimal for our particular use profile. Several marine providers have already figured this out. I guess time will tell with Trojans entry into lithium. They seem to be proceeding very cautiously though, as if unsure of the product.

Interesting. That doesnt seem to completely in alignment with the references you cited as being 'the word' on Lithium batteries.

I guess many of the experts might think that theory as a bit misguided?

What would I know, everyone's entitled to their opinion right.

[kmacdonald]

Originally Posted by tanglewood

Just curious, what marine vendors started with LFP and have dropped it for something else?

They dropped lithium altogether.

Historically boater used LA batteries because that was what was available from the aoto industry. Lead, being very heavy is not an optimum material for use in boats where weight matters. Boaters settled on what was available. LA batteries evolved and some of the issues were mitigated to some extent but they still leave lots of room for improvement.

Some of the newer "drop in lithium" marine battery companies have a very aggressive advertising campaign but no track record of success. Trojan may change that, we'll see.

LiFePO4 has it's niche market in the marine industry but hasn't grown to being standard equipment on new boats. They have been available for a long time and their properties make them well suited to boat use with the exception of a few negatives. The negatives have trumped the positives.

You are very knowledgeable and have a technical background and that's a good fit for a lithium implementation. Most boater don't fit that mold. I'm sure you know there are Trojan Industrial batteries that have equal or greater cycle life to LiFePO4 but they ave heavy. In a Nordhaven it wouldn't matter that much so I assume you have lithium because you enjoy the challenge.

[kmacdonald]

Originally Posted by tanglewood

I’m still not seeing it. Victron, Lithionics, and Mastervolt all seem to be growing and likely here to stay. Lots of little garage shops have failed, but I’ve seen nothing to suggest it was because or their choice of LFP over other variants. And Battleborn seems to be getting some traction in the drop-in market.

At least one and I think several of the companies that stopped selling LiFePO4 systems said they did so because the batteries were too inconsistent.

[CatNewBee]

LiFeYPO4 is not yet a consumer mass market. But they are used in automotive, storage and military applications including the marine (in chinese sub marines for example).

The main problem is that big manufacturer try to build proprietary systems for a premium price and most customers are not willing to pay for it. That is the reason why they are rare (see Victron, Mastervolt etc.). You can buy a new boat with lithium batteries - even for propulsion nowadays. Most simply do not want to pay the premium and the big player do not want to produce compatible batteries than can be used in heterogeneous systems, they want to be a wholesale solution provider including life long service contract. That is the reason Victron invests more in the CCGX and Internet monitoring / remote maintenance instead of battery and BMS development.

They all want to make money with services instead of products.

[newhaul]

Originally Posted by rgleason

Newhaul:
The 62% of banks total capacity is really from me, using 20%SoC as the lowest which is xx vpc and highest voltage 13.88v (3.47vpc) using a charge rate of 0.35C.
and the charge curve from the Lund Co Powermiser website that I linked to.

The 7000 cycles is just from winston battery specs and John suggesting to use that as the bottom. Should I be using cell voltage?

In your experience actually using LiFePo4 what do use as top and bottom and what are the SoC?
And what do you think is the no cycles?

so far I only have about 20 cycles on my bank . So no clue how many I can expect. ( likely more years worth than I have .

My solar controller is set for the following top end 13.8 (3.45 per cell)
on the bottom I have the feed set to cut out at 12.1 (3.025) . I have yet to hit that low point.
I manually connect the panels when I hit 12.4 (3.1 ) . Which is about every 4 days . As of now I am still working on my refer system install so my daily power needs are quite low . ( less than 15ah)
most of that is my diesel furnace.
All led lighting .

For now I only have the 200 watts rigid solar hooked up so takes a few days ( in winter ) to recharge my bank. I get between 20 and 30 ah per day into the cells.

[Delfin]

Originally Posted by tanglewood

I don't really agree. I do agree with your implication that the majority market gets to write the rules, and in this case that's likely EVs. But I don't agree that we will all end up with one chemistry, driven by EVs. Just look at the diversity of chemistries today, and not because of rapid development. NiCad and NiMHi are still abundant, as of course is LA. All have their place and fit, apparently enough so to create a viable market for them.


As for power density, that matters a lot in many applications, but matters very little in others, including boating (other than perhaps competitive racing). Yet in boats, fire protection is paramount, and LFP has much better characteristics compared to other Li chemistries. I'll take fire protection over power density any day. I personally think that NMC and some others have no place on a boat, and am quite surprised that some vendors are pushing them. If a car starts to smoulder and catch fire, you can pull over, get out, and walk away. No so much with a boat...


And I'm not sure where you are seeing wide variation in properties between vendors. I've seen just the opposite.


As for Trojan and other "drop-in" vendors, I think they are smart to go slow. Many of us think there are one or more train wrecks waiting to happen with such products. I only hope they have a net positive on the overall market, rather than tarnishing it.

Your point about energy density is key. EV holy Grail is Mr. Fusion since weight is critical to case performance. On a boat, not so much, which is why LFP's safety, flat CAR with minimal taper makes this chemistry ideal for boats. I couldn't care less if my battery weighs 100# or 1000#.

[Delfin]

Originally Posted by kmacdonald

LiFePO4 has it's niche market in the marine industry but hasn't grown to being standard equipment on new boats. They have been available for a long time and their properties make them well suited to boat use with the exception of a few negatives. The negatives have trumped the positives.

.

I guess I'm not clear why you would quote as authoritative two sources of information - Maine Sail and Nordkyn - who take the opposite position to yours on this chemistry. If you disagree with them, have you others you could reference that support your position?

[kmacdonald]

Originally Posted by Delfin

I guess I'm not clear why you would quote as authoritative two sources of information - Maine Sail and Nordkyn - who take the opposite position to yours on this chemistry. If you disagree with them, have you others you could reference that support your position?

I'm not against LiFePO4. I've pointed out that it hasn't been successfully integrated into boats on a large scale after being on the market for a long time.
Other chemistries are being used in large scale Battery Energy Storage Systems (BESS) market more than LiFePO4 and the marine market will follow. That will be what's available at reasonable cost.

Just because LiFePO4 is considered a safe chemistry doesn't mean others aren't.

[kmacdonald]

Originally Posted by Delfin

I guess I'm not clear why you would quote as authoritative two sources of information - Maine Sail and Nordkyn - who take the opposite position to yours on this chemistry. If you disagree with them, have you others you could reference that support your position?

MainSail suggests getting LiFePO4 batteries with consecutive serial numbers. This indicates he knows there is a problem with QC or how intolerant the chemistry is to impurities. LA battery quality is VERY dependent on lead purity and trace amounts of other metals can have large adverse effects.

[Delfin]

Originally Posted by kmacdonald

MainSail suggests getting LiFePO4 batteries with consecutive serial numbers. This indicates he knows there is a problem with QC or how intolerant the chemistry is to impurities. LA battery quality is VERY dependent on lead purity and trace amounts of other metals can have large adverse effects.

I don't think MS's recommendation says anything of the sort, but is a reflection of the desirability of purchasing sequential production units when maximum uniformity between units is desired. In the case of batteries, AFAIK the uniformity desired is the same internal impedance.

[kmacdonald]

Originally Posted by Delfin

I don't think MS's recommendation says anything of the sort, but is a reflection of the desirability of purchasing sequential production units when maximum uniformity between units is desired. In the case of batteries, AFAIK the uniformity desired is the same internal impedance.

That's just another way of saying just what I did. If you buy battery model X it should be exactly the same as another, same brand, battery model X. If it's not then there are QC issues.

[evm1024]

Originally Posted by kmacdonald

That's just another way of saying just what I did. If you buy battery model X it should be exactly the same as another, same brand, battery model X. If it's not then there are QC issues.

Well, you just invalidated your opinion in these matters.

[kmacdonald]

Originally Posted by evm1024

Well, you just invalidated your opinion in these matters.

No, you clearly misunderstood SOMETHING, I don't know what but SOMETHING. If a battery technology requires sequential serial numbered batteries to function correctly in a pack, it's just not going to work. Next time you order a set, specify sequential serial numbers and let us know what they say. Part of the beauty of mass production is that ALL the items produced come out the same within reason. If not something went wrong or the allowable tolerance is too large. We all know they won't be exact but if they aren't close enough to work in a pack, any pack with the same battery, then the tolerance is too great. Unfortunately that seems to be the case. Don't take my word for it, read what some of the pack builders that quit selling them said. My best guess is that most of the prismatic cells end users are able to buy are factory rejects.

[kmacdonald]

Four or five years ago when I was shopping for 4 small capacity LiFePO4 cells I used google to search for them. I would click on the links found and call about pricing and availability. A common response was "we don't sell them any longer". Failure rate was often cited as the reason.

[tanglewood]

Originally Posted by kmacdonald

No, you clearly misunderstood SOMETHING, I don't know what but SOMETHING. If a battery technology requires sequential serial numbered batteries to function correctly in a pack, it's just not going to work. Next time you order a set, specify sequential serial numbers and let us know what they say. Part of the beauty of mass production is that ALL the items produced come out the same within reason. If not something went wrong or the allowable tolerance is too large. We all know they won't be exact but if they aren't close enough to work in a pack, any pack with the same battery, then the tolerance is too great. Unfortunately that seems to be the case. Don't take my word for it, read what some of the pack builders that quit selling them said. My best guess is that most of the prismatic cells end users are able to buy are factory rejects.

But this just isn't the situation. We all have our own crystal balls about what the future holds, but so far none of the concerns you have brought up actually exist in any detrimental way.