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john61ct · 13-08-2018, 05:22

Quote:

Originally Posted by jkleins

You also assume poor quality is synonymous with "drop-in" and I can't argue that that is the current state of play as I don't know, but it doesn't necessarily have to be does it? Can't BMS devices be built-in to the battery that are good quality?

Not so much that they definitely **are** poor quality.

Just that we have no way of knowing the actual quality, with respect to longevity, until a given brand has been widely used for a decade or so.

The consensus is that known-good quality bare-cells are made by say a half-dozen companies in the world.

And this market segment is worldwide rife with outright thieving scammers, up to the normal marketing deception even reputable companies like Trojan practice.

If the company does not release the source of their internal cells, their sealed-up product prevents their identification by the buyer, and using sub-par cells greatly increases short-term profitability

then it is fair to say chances are high that quality will be low.

Now, outfits like Victron and Mastervolt (not bolt) have a strong incentive to preserve their stellar worldwide brand reputation long term, so to that extent perhaps they can be trusted.

But personally, since longevity-quality can vary from one cell to the next, and verifying that those individual cells are closely in balance with each other is a key diagnostic for state of health,

I prefer a setup that makes them accessible.

OceanPlanet · 13-08-2018, 05:37

Quote:

Originally Posted by Hoopla

Bruce

I pride myself knowing what who makes what and as far as Lithionics concerned always went to the external BMS as the best out there and as their system sales suggest.

The fact Lithionics internal packaged BMS/Contactors (while not my cup of tea) but fully featured, also comes with external communication I have totally missed. Lithionics should make that feature more visible to differentiate their offering to the Drop-In rubbish.

Agreed. We certainly don't control all of Lithionics sales (they are growing fast in other markets, especially RV & motorhome sector, and having even supplied a custom battery to the Tesla factory), however they are sending nearly all of their marine sales to us to handle now. So at least for the marine market we can vet each config and make sure all is properly sorted. Which is why they are sending us those projects in the first place, so they don't have to...;-)

Hoopla · 13-08-2018, 06:37

Quote:

Originally Posted by john61ct

For any DC charge source without user-adjustable setpoints, output can be routed through Sterling BB line DC-DC chargers.

Putting the lead batt load dump on the same circuit as the LFP bank will indeed help buffer spikes from unexpected cutoff events from the internal BMSs.

Cheap, even sacrificial, no need to ensure a proper charge profile for that.

No, any LFP 4s pack can tolerate those levels just fine.

It's just that this high charging voltage will only get the customer past the warranty period, or maybe the batt's rated lifetime cycles,

not the **much** longer life it would have at lower voltage, avoiding the shoulder.

> "discharge up to 100%"

My 100% DoD is defined as 11.9V, just as my 100% Full SoC is defined as 13.8V. Assuming low current rates.

These are arbitrary choices made by the owner.

The vendor LVD cutoff may be lower, but it certainly is not at an instant & permanent death-level low voltage,

> at around 25% SOC LFP cells turn into cats each with their own voltage and when measured on pack voltage basis that is irrelevant. Cell damage is about to occur.

Not so. Depending on discharge rate, 11.9V is around 10% compared to vendor zero, and still well above the immediately dangerous low-shoulder area of the SoC/voltage curve.

Yes, lifetime cycles are reduced by higher DoD, as with any batt, but that is a decision for the owner, not a hard bright line, but a smooth greyscale curve,

and so, if a higher cutoff is automated, that is more "user level" protection, not BMS functionality. The Victron BMV relay could be well used for that, as well as user-adjustable LVDs at higher setpoints fronting specific non-essential load devices or circuit groupings.

What are:

WIP
ydtms

?

John I'm on a long distance continental train journey and only using my phone and don't now how to selectively quote reply etc. I don't question at all your reply but maybe you should consider say context of my Delos piece before typing and I pick one example that know how to highlight.

You said my 25% SOC for cells turning to cats was effectively nonsenese and dependant on discharge rate. I agree with the latter but not the former. I made that in the context of Delos with an electric cooktop, microwave all happening as cooks do. All that via an inverter is a discharge rate of 0.3C+ all day long and I guarantee at 25% SOC the cats come out to play exactly as I said. Conversely with a small system struggling with say the addition of intermittent AP loads pushing loads into the 0.3C arena it is exactly the same result.

So I suggest if you have a reply beckoning then please do so in context..I have already acknowledged your LFP dick is bigger than mine upthread so why the constant challenge using tech lauguage interspersed with personal LFP indicators most here don't even understand?

No one learns anything from that and I can assure you I don't need your education.

Ignore this hint and keep it up simply means I have no interest contrubuting here.

Delfin · 13-08-2018, 06:54

Quote:

Originally Posted by Hoopla

The term "Drop-In" is clearly not understood.

It refers to LFP batteries incorporating an internal BMS that can't communicate externally AND incorporates high and low cut off voltages beyond the range recognised as being acceptable for LFP.

With those out of range voltages it can then be marketed as a "drop-in" substitute for Lead Acid WITH NOTHING ELSE REQUIRED.

Lithionics also in addition to their external BMS line have a self contained offering utilising an internal BMS but fully featured and with correct HVC and LVC's and so they DON'T market it as a "drop-in" substitute for LA.

Your belief that most people already have programmable charge sources and or an understanding of things battery in my experience is far from correct.

Three decades of seeing GEL batteries marketed as "drop-in" replacements for FLA and murdered and likewise AGM's burning up small case auto style alternators or being killed with excessive DOD's and or not being regularly returned to 100% SOC confirms that belief.

The marketing of LFP as "Drop-In" simply shows this same path is being travelled again where wallets will be emptied and the reputation of another battery chemistry trashed by the people selling them with no disclosure.

I guess like the Red Queen, drop-in means whatever you want it to mean. In my case, it meant consulting with the engineers at Lithionics, buying the batteries, putting them in the box the AGMs came out of, adjusting the Balmar 624 and Trace 4000 for correct charge voltages, and using them.

I believe you will find, if you read what I wrote, that I said that "many" people, not "most", use programmable regulators. If one does't, then as part of a new Li install, you'd want to upgrade the charging equipment just as you would upgrade fuel filtration if you switch out to a tier 4 diesel. But I gather your definition of drop-in means a battery that either doesn't have a BMS, or if it does, has one that is incorrectly configured for the chemistry, and where the purchaser has 1980's style voltage regulation and chargers. I guess I should say 1970's, since my Ample Power VR was fully programmable and I believe I purchased that in the 80's.

Hoopla · 13-08-2018, 08:44

[QUOTE=Delfin;2695159]I guess like the Red Queen, drop-in means whatever you want it to mean. In my case, it meant consulting with the engineers at Lithionics, buying the batteries, putting them in the box the AGMs came out of, adjusting the Balmar 624 and Trace 4000 for correct charge voltages, and using them.

I believe you will find, if you read what I wrote, that I said that "many" people, not "most", use programmable regulators. If one does't, then as part of a new Li install, you'd want to upgrade the charging equipment just as you would upgrade fuel filtration if you switch out to a tier 4 diesel. But I gather your definition of drop-in means a battery that either doesn't have a BMS, or if it does, has one that is incorrectly configured for the chemistry, and where the purchaser has 1980's style voltage regulation and chargers. I guess I should say 1970's, since my Ample Power VR was fully programmable and I believe I purchased that in the 80's.[/QUOTE]

"guess like the Red Queen, drop-in means whatever you want it to mean"

Actually it doesnt. It is a well understood term amongst professionals, only in places like this it gets discussed.

"and where the purchaser has 1980's style voltage regulation and chargers. I guess I should say 1970's, since my Ample Power VR was fully programmable and I believe I purchased that in the 80's"

Firstly it may surprise you but the world is a big place. Courtesy of tariffs, exchange rates etc don't think what is available in one's own back yard is available worldwide. In some places your 1980's experience was cutting edge not so long ago for low volume specialist gear.

Secondly I note your personal view of the market place as a consumer being contrary to mine. Mine is over 3 decades being in this business as a provider trying to understand that to make a living and so have skin in the game. That said I defer to your wisdom.

john61ct · 13-08-2018, 08:51

Quote:

Originally Posted by Hoopla

You said my 25% SOC for cells turning to cats was effectively nonsenese and dependant on discharge rate. I agree with the latter but not the former.

I never used the word nonsenese, and sincerely, nothing here is personal, no dicks involved (really?)

maybe I could be less direct and more friendly,

I am not addressing you in any case, feel free to just ignore my posts. There are hundreds even thousands using these forums,

to me providing accurate information to anyone reading is the primary goal.

Anyway, no matter the context, I am certain that using quality LFP in the 10-25% SoC range does no harm,

beyond the incremental wear and tear resulting in shorter cycle lifetime inherent in drawing deeper. Just like going to 30% is "harmful" compared to only using 50%.

I'm not fully understanding the cats analogy, but. . .

A high rate of discharge will drop voltage **more** relative to SoC. Another way is to say the bounceback to resting voltage will be higher after heavy discharge currents.

Therefore it's more dangerous to go below 12V with a low amp current than a high C rate.

Just like a lower charge setpoint is required for solar as opposed to a 200A source.

It is true that cell-level balancing is less of an issue by avoiding the top and bottom shoulders, but IMO sacrificing more than 15% of such expensive rated capacity (given quality prismatic cells) is not required to get excellent longevity.

john61ct · 13-08-2018, 08:57

wrt a useful definition of "drop-in" LFP

99.9% of them have no access to the internal cells, nor communications between the inside electronics and the outside world.

Therefore I think that the term used without qualification can assume those as defining characteristics.

Since the Lithionics version is the first exception to the rule that I've come across, when their comms feature is relevant I'd just try to avoid lumping them all in with the others.

Delfin · 13-08-2018, 09:03

For those considering actually purchasing and using Li batteries rather than working to establish themselves as experts in the subject, here are my two cents based on my installation, and my desire not to spend the time building my own system from individual cells:

1. They are expensive, but if you intend to use them a lot and for a long time, they are cheaper per cycle. If you do not discharge them 80% on each cycle, the lifespan of these batteries is in the many thousands. If you do, then they are still likely in the 2,000+ range.

2. I find the rapid charge time with virtually no taper plus the stable and higher voltages they deliver over a cycle to be the most significant benefits.

3. Most of the sturm und drang that surrounds this topic is based on some people's insistence that one be able to set up a Li bank and them have charge cycles managed electronically without user involvement, just like your good old LA bank allowed you to do. That is, IMO, a waste of time.

4. If you simply charge these batteries to 96 - 98% of capacity, they will accept whatever charge current you have available within reason. In my case, that is 200 amps @ 24 vdc into a 600 amp bank. When the acceptance rate of current drops from 200 amps to around 30, I take the Li bank off line by pushing two buttons on the Lithionics BMS and then run on my LA starter bank. When I get to anchorage, I bring them back on line, draw them down around 50% and then recharge the next day.

5. I have the Balmar and Trace set at 28.8 vdc, with the minimum absorption of a few minutes on the Balmar and none on the Trace. Float is set at 26.8 vdc. I also have the Ample Power 130 amp alternator throttled to a max of 100 amps to keep it a bit cooler. However, the batteries never see 28.8 vdc, unless I have slipped into coma or forget to take them off line once charged. If I have fallen asleep, then the charging system as configured will drop voltages quickly with no harm done, but since I can pay generally pay attention to the charge cycle that has happened about once over the last two months of cruising.

6. The advice from some to only charge these batteries to a max voltage below 14/28 might work if your bank sits on a bench, but doesn't on a boat. Equipment coming on line, going offline as you putter along just means your smart charging equipment will trip to float when the battery is only partially full, and since you really can't tell how full a Li bank is at any voltage below 14.1/28.2 you have no clue if you are cutting its usable capacity in half, by a quarter, or something else.

7. Since the time it takes for my batteries to go from accepting 200 amps to accepting 30 is just over 4 minutes, at which case they are as full as they need to be, CMS's advice to charge until "full", then disconnect from charging makes perfect sense. To do this and still run the boat underway or at the dock, you need a starter LA bank so that charge current has a destination once the Li is full. I direct charge current to either bank using a Blue Seas automatic combining relay rated for the purpose that was already in place when I installed the Li bank. When charging or using the Li bank, the Li BMS is on, and the ACR is in the auto switch position. When I want to take it off line, the ACR gets switched to Manual combine and the BMS gets switched off. While this represents a manual process I would submit that if you can't manage the level of situational awareness this requires, you probably should find another hobby than boating since you will likely be on the beach in short order.

While it would be nice to be able to have my charging systems manage this new chemistry without my involvement, it would also be nice to have my engines check their own oil levels, my radar to automatically keep me from running into things and my water maker to change its own filters. However, I accept a certain level of responsibility in these matters so as not to kill my investment (or someone else), so accept that if I am to have the benefits of lithium batteries, I have to pay attention.

This is just how I am using these batteries, and others needs will dictate different approaches, especially with regard to solar which I know nothing about nor have. Bottom line, I have not found this to be anywhere near as complicated or danger strewn than some would have one believe.

Delfin · 13-08-2018, 09:12

Quote:

Originally Posted by john61ct

wrt a useful definition of "drop-in" LFP

99.9% of them have no access to the internal cells, nor communications between the inside electronics and the outside world.

Therefore I think that the term used without qualification can assume those as defining characteristics.

Since the Lithionics version is the first exception to the rule that I've come across, when their comms feature is relevant I'd just try to avoid lumping them all in with the others.

Here's another then.....https://www.navitassys.com/products-...t-systems-bms/

https://www.navitassys.com/wp-conten...et-11-9-14.pdf

Beats me if these folks know what they're doing but perhaps your statement that "99.9% of them have no access to the internal cells" is a bit of an overstatement?

nebster · 13-08-2018, 09:13

Quote:

Originally Posted by john61ct

I'm not fully understanding the cats analogy, but. .

I took it to mean that a series string of cells that are not bottom-balanced will start to diverge at the bottom of the discharge. As in, the voltages will start to run all over, like cats?

I can't imagine a small 4s pack with cells so out of whack that they would diverge that much at 25% SOC, however. I only have divergence data for top-of-charge (because I went with bottom-balancing), but at 75% SOC LFP is still well within the linear part of the voltage curve. It is closer to 90 or 10% SOC where the fun begins.

CatNewBee · 13-08-2018, 09:26

I had a tough read of the last 4-5 pages.

A lot of religious content from believers and non-believers.

First thing first

1.) THE ALTERNATOR.
is usualy designed to charge a small LA start battery.
All the issius reported from burned alternators stem from this design goal an also apply, if you connect a big empty 1000AH LA bank to them. They are not made for house banks in the first place. Another issue is, EVERY charge source should be self-protective to high currents (short circuits), reverse polarity, overheat etc. If this is implemented, no worries with LFP FOR THE alternator, they are set around 14.2V, far below dangerous voltages for LFP too.

2.) Self-contained BMS
I simply not trust 1 fits all strategies. Either you limit the ability of the cells by to weak electronics (very common) or you spec them to handle 3C, than the electronics will be bigger and more expensive than the cells used. Its waste of money, to have 10 BMS, 10 Power regulators etc. Also in serial installation you may have to deal with the double voltage in case of a failure - opposite to a proper 24V system with a single BMS.

I would only use a drop in, when the manufacturer delivers a FULL documentation of the used internal circuitry - what they won't do. You just get a marketing spec sheet.

3.) Chinese Cells vs US Cells.
I dont see any advantage of made in USA vs. China. China has more experience in building LFP cells, is the market leader, the processes are burned in for several years, they are mass manufacturer for all kind of brands around the world. Its like TV screens or smart phone displays. There is no noteworthy foreign manufacturer to compete. It is simple technology inside, btw. Thats what China is best at.

nebster · 13-08-2018, 09:27

Quote:

Originally Posted by Delfin

6. The advice from some to only charge these batteries to a max voltage below 14/28 might work if your bank sits on a bench, but doesn't on a boat. Equipment coming on line, going offline as you putter along just means your smart charging equipment will trip to float when the battery is only partially full,

Can you say more about this? I agree with everything else you wrote, but this doesn't ring true in my experience. I might be misunderstanding what you wrote.

I have an automated (not sure I would go so far as to call it "smart") charge system that works great in the real world, and it does not "trip to float" when loads change. I have my CV threshold set substantially lower than 3.525v, and this virtually guarantees that my pack will not charge above roughly 90-92% SOC.

Quote:

and since you really can't tell how full a Li bank is at any voltage below 14.1/28.2 you have no clue if you are cutting its usable capacity in half, by a quarter, or something else.

Sure you can, that's what coulomb counters are for. They drift a bit, but they're plenty good enough to tell you whether you're at 20% or 50% or whatever. That data can be used to as an input to charge decision-making, too.

Hoopla · 13-08-2018, 09:29

Quote:

Originally Posted by john61ct

I never used the word nonsenese, and sincerely, nothing here is personal, no dicks involved (really?)

maybe I could be less direct and more friendly,

I am not addressing you in any case, feel free to just ignore my posts. There are hundreds even thousands using these forums,

to me providing accurate information to anyone reading is the primary goal.

Anyway, no matter the context, I am certain that using quality LFP in the 10-25% SoC range does no harm,

beyond the incremental wear and tear resulting in shorter cycle lifetime inherent in drawing deeper. Just like going to 30% is "harmful" compared to only using 50%.

I'm not fully understanding the cats analogy, but. . .

A high rate of discharge will drop voltage **more** relative to SoC. Another way is to say the bounceback to resting voltage will be higher after heavy discharge currents.

Therefore it's more dangerous to go below 12V with a low amp current than a high C rate.

Just like a lower charge setpoint is required for solar as opposed to a 200A source.

It is true that cell-level balancing is less of an issue by avoiding the top and bottom shoulders, but IMO sacrificing more than 15% of such expensive rated capacity (given quality prismatic cells) is not required to get excellent longevity.

to me providing accurate information to anyone reading is the primary goal.

You and me both John. I apologise going personal, I'm not very good at this internet discussion thing. Great respect for your words. Cheers.

nebster · 13-08-2018, 09:39

Quote:

Originally Posted by CatNewBee

I dont see any advantage of made in USA vs. China. China has more experience in building LFP cells, is the market leader, the processes are burned in for several years, they are mass manufacturer for all kind of brands around the world. Its like TV screens or smart phone displays. There is no noteworthy foreign manufacturer to compete. It is simple technology inside, btw. Thats what China is best at.

I agree. However, there are no USA-made LFP storage cells anyway, so it's a moot point.

A more interesting question is whether "off brand" manufacturers' cells can be any good. My experience, a sample size of 1 (or 112, depending on how you want to count) says yes. However, I did have 2 out of 112 cells DOA.

Then again, someone else building a 32-cell CALB pack just a few weeks ago found 1 out of 32 DOA, too.

Some of the cells made by the lesser-known companies are more advanced technically than what you can buy from CALB or Winston -- both higher volumetric and higher gravitational density.

Where that leaves a buyer, I don't know. Depends on how much you feel like gambling, I suppose.

I do know you can get cells for right at $0.25/kWh right now FOB Shenzhen, so in my opinion it's probably a toss-up, since a DIY builder should be qualifying every cell anyway. Just buy some extra, throw out the bad ones, and carry a few extra cells on board in case something happens down the road.