'on board' 1.5kW charger. Which alibaba supplier?

[john61ct]

Similar discussion wrt LTO and faster rates but same principles of course here

https://endless-sphere.com/forums/viewtopic.php?p=1549031#p1549031

 

[flippy]

we are not talking about LFP cells, "AHT" or whatever. just regular old lithium and we will use the normal terminologies and industry defenistions, not make up your own. dont change the goalposts and just accept you are wrong and have no clue how this stuff actually works.

once you have accepted you are wrong we can move on and teach you how to be correct and focus on you giving correct advice to people that read these forums.

 

[DogDipstick]

ular old lithium and we will use the normal terminologies and industry defenistions,

once you have accepted you are wrong we

advice to people that read these forums.

Flippy, you told us to charge a 2.75Ah cell at 8 amps. Already in this discussion. If you wish for you knowledge to be relative, and relevant, educating, please proofread; for your mistakes can be confusing, whether they are purely grammatical or, something we dont have knowledge of, or something we might wonder in disagreement over. Pls.

I hope you did not skip over reading that, for I know you like to tell me that you "dont read what I write," and, do so often.

ITERM - Definition:


Current C/? is a standard lithium type termination that stops the charge when the current is below a ratio set by the charge current. Typically Termination should be C/10.

Is it? Or is it not? By definition. Industry Standard... ?

Yes it is. I understand the datasheet, my friend. I can read English and understand what the words mean.

"normal terminologies and industry defenistions" as you call it.

If we look at termination currents and teh application of "1mA" trickle... we must account for the volume and density corresponding.

Some say a c/5 is BETTER cause the cell NEVER fills up and you are only charging to 90-93% or some shit.

I say it is specific to the dells design, and the resistance climbs at top and bottom of charge/discharge. Nature of a mature cell design. You know.....

......cannot compare a 3A, 2Ah 18650 to a 60A,60Ah lithium cell., when examining termination current. We must make the discrepancy. We must come to the same page it we desire context to our debate ( assertion)(s).

I get rated capacity when I follow the instructions. When I dont, I dont.

I can charge up a 40Ah Farris (ZERO) cell to C/10, and it will put in 38Ah.

.....taper as the datasheet says, ( C/50) all of the sudden, I get... 40.5Ah ( what the sheet says I will get). Explain that Mr.MojoBatteryHo. Should I sell that cell as a "38Ah" cell, or a "40Ah" cell? Given the customer expects 40,.

There is:
NO Taper.. ( lacks rated capacity of cell)(longevity)
Tapering, ( correctly) (full rated SOC) and
OVertapering ( detrimental).

As I see it from the empirical test I do. On congruent cells.

I could do it on log right now if yall would like. 8x rof repeatability easily.

 

[flippy]

Flippy, you told us to charge a 2.75Ah cell at 8 amps. Already in this discussion. If you wish for you knowledge to be relative, and relevant, educating, please proofread; for your mistakes can be confusing, whether they are purely grammatical or, something we dont have knowledge of, or something we might wonder in disagreement over. Pls.

I hope you did not skip over reading that, for I know you like to tell me that you "dont read what I write," and, do so often.

it was not a mistake. the cell can take that. as stated in the datasheet and by my own testing.

that stated, doing a 8A charge/discharge on that cell every time will murder it in <200 cycles as i have tested it myself. (as the datasheet also warns about) but lifecycle is not part of the discussion.

we are not discussing lifespan.cycle life or whatever, we are discussing fundamentals. as you both dont seem to understand those.
once we get the fundamentals down and you understand how the charging process -actually- works we can discuss lifespan and other factors.


explain to the audience how "overtapering" works in the charging process of a single regular 18650 cell as i specced out before and explain as well what the frock "overtapering" means. (i love people trying to explain shit they made up)

 

[DogDipstick]

Flippy,

it was not a mistake. the cell can take that. as stated in the datasheet and by my own testing.

that stated, doing a 8A charge/discharge on that cell every time will murder it in about 200 cycles. (as the datasheet also stated)

every datasheets is EXTREMELY clear on what NOT to do. dont overcharge, overcurrent, overdischarge, puncture it. whatever. NOWHERE does it say you must terminate the charging process to prevent damage or overcharging or anything else. the only time where termination is mentioned is in the parameters the manufactuer used to validate their product.

I do understand this ^^^^Clearly and concise to the point.

Really? You can charge a 2.75Ah cell at 3C? Thats not dangerous? I do not see where in the cell data is says this. COuld you please maby point it oot? You did say it is is in the data.

I did not think 3C is typical for an 19650.

Its a FOURTYFIVE MILLIOHM cell for Christs sake. BAhahahaha. Half a hundredth of a OHM! HIgh like a High end hooker.. All kinds of hot and expensive.... the harder you "Hit" her.

Screw cycle life, Eh? Lol. I would not say that is in application, recommended at all by any manufacturers,and they would not allow a civil claim ( legal claim against the company) if it is proven by the consumers that the contract stipulation was breached. .

 

[flippy]

dude, focus on what is the actual issue.

lets recap: you cant read datasheets. you made conclusions based on that and now is telling everyone false infomation to everyon that reads these forums. that shit needs to stop.

you cant even answer simple question i ask to explain your positions. you dont even know what the datasheet data actually means or why they tell you it.

lets put focus on some basics here and just show you plainly how stupid you actually are making yourself look here.
focus on this question and this question alone:

WHY does the datasheet tell you that -in the safety section- (big clue here) the standard charging process must be finished in 3 hours OR 1/20C?

 

[DogDipstick]

explain to the audience how "overtapering" works in the charging process of a single regular 18650 cell as i specced out before and explain as well what the frock "overtapering" means. (i love people trying to explain shit they made up)

By your e=xample before of sitting a charged cell at a current of 1Ma

Yes is made up, for that IS why I did quote the statement, clearly, for i am an amatuar and do not know the correct terms ... ( I suppose it owould be "Too LOW of a termination current)

There is "too much.". "not enough".. and "JUST RIGHT".... GOLDILOCKS taught me that. Personally. When I was a kid.

Also, I did not make it up. I pulled it from a random White paper on the web. C'Mon you dont think Im smart. You think Im dumb. Think I made that shit up? Nah lol. I steel references.
Random, not industry standard, uninformative, and blankly incoorect statement form some random white paper on the web. Probally made up by some random idiot who knows nothing. Blank Blanket statement.

"Selecting a charger that uses minimum charge-current termination (C/10 or C/x) can also extend battery life by not charging to 100% capacity. For example, ending a charge cycle when the current drops to C/5 is similar to reducing the float voltage to 4.1 V. In both instances, the battery is only charged to approximately 85% of capacity, which is an important factor in battery life."

You aint gonna stop me. I am incorporated. Lol.

 

[DogDipstick]

WHY does the datasheet tell you that -in the safety section- (big clue here) the standard charging process must be finished in 3 hours OR 1/20C?

WHy?

Also: I still dont see where ti says it can ( 29E) can tke 8A.... I DO see it says MAXIMUM charge is

"2750mA (not for cyclelife)"

..WOW you can really do 8A safely until EOL? Coolio.

Am I misinterpreting the work "maximum?"

I do see this, on the "TESSTING" sheet, though...

[ Caution! ] ■ Electrical misusage Battery must be charge with constant current-constant voltage (CC/CV). Charge current must be controlled by specified value in Cell specification. Cut-off Voltage of charging must be 4.20V Charger must stop charging battery by detecting either charging time or current specified in Cell’s specification. Discharge current must be controlled by specified value in Cell’s specification. Cut-off Voltage of discharging must be over 2.5V.

AND:

10. Warranty Samsung SDI will be responsible for replacing the cell against defects or poor workmanship for 1year from the date of shipping. Any other problems caused by malfunction of the equipment or unsuitable use of the cell are not under this warranty. The warranty set forth in proper use, handling conditions described above, and excludes in the case of a defect which is not related to manufacturing of the cell.

Huh I wonder why they need a WARRANTY statement aboot a TEST criteria.

Replace the battery when using time of battery becomes much shorter than usual.

YOu run into that alot in testing?

 

[flippy]

WHy?

because you need to prove you actually understand what you are people telling that you know. i am just showing that you dont know and are talking out of your ass.

if you are so good with all this: tell us.


and yes, i run these tests at well beyond specifications because i need to know what cells can and cannot take and how they wear out under certain conditions above and below their ratings. like like a car maker runs their engines to redline and beyond to see how long they survive and what happens i need to know as well. because then i can also see and understand when a customer has been mistreating my products and starts bitching about warranty. it beign over the redline or if it has been running idle for years.

but this is still way beyond your level. lets stick to the basics here for now and explain the WHY i asked you.

 

[DogDipstick]

WHy?

because you need to prove you actually understand what you are people telling that you know. i am just showing that you dont know and are talking out of your ass.

if you are so good with all this: tell us.



but this is still way beyond your level. lets stick to the basics here for now and explain the WHY i asked you.

like like a car maker runs their engines to redline and beyond to see how long they survive and what happens i need to know as well.

"Beyoe my level" then decides to edjumacate me aboot heat engirns.


Lol "redlines " are well engineered virtually before any harmonically balance engine gets to production. It is an easy math.

By engine manufacturing companies.. Like Beckersille Steam Engineering, Inc.

Since Day 1 of engine design. Lol. 100%.

GTFO. They dont just " see when it blow up" by RPM. Not at all. Harmonic balance and critical RPM is calculated, not empirically derived, certainly. Billion dolla turbine installations KNOW the critical RPM through deduction, and product, rather than " see when it blows up" .

We currently have 400,000$ in the engine we are contracted to design, draw, manufacture, and build ringt now. Dont tell me bout heat engine design, friend. I know alil boot that.

Wanna see this engine? Its going into a 200ft ship.


I asked

"WHY does the datasheet tell you that -in the safety section- (big clue here) the standard charging process must be finished in 3 hours OR 1/20C? ",

not for your opinion of my knowledge, friend.

I seek knowledge, not argument.

 

[DogDipstick]

Telling me the wording of "maximum" in the datasheet is not concrete.

Really? Lol. I dont get it. One second you say the data says one thing, another instance you say you can do what you want. We get it you are special.

lets recap: you cant read datasheets. you made conclusions based on that and now is telling everyone false infomation to everyon that reads these forums. that shit needs to stop.

That is your argumentative "Opinion", that I cannot.

I can read datasheets, and you know it. You aint gonna stop me. Lol.

It is by "definition".

YOU SAY:
For your convenience, you can ignore teh specified termination current on the sheet.
But, also, for your convenience, you can disregard the definition of "MAXIMum"...

But.. THEY SAY (SAMMYSONG) they wont warranty the " test?sale?" if you do, for their, "convenience".

I see. Storage battery engineering relies upon "convenience". NOt metrics, or the like, as printed, on the data, sold with the cells,.

I do not get your argument. Does not seem infallible.

The first engineer-designed heat-engines are still turning to this day. The best of them. For about 170 years by now. Still round, still running undr the calculated design speed, or near the "redline" as you call it... Whatever that is. Trust me, they did NOT " test them till redline" as you state, when they were manufactured.

The engine speed was engineered, with the harmonic orders, of balance. Not empirically derived, as you state.

How is that for a time test.

 

[DogDipstick]

[ Caution! ] ■ Electrical misusage

Battery must be charge with constant current-constant voltage (CC/CV). Charge current must be controlled by specified value in Cell specification. Cut-off Voltage of charging must be 4.20V Charger must stop charging battery by detecting either charging time or current specified in Cell’s specification. Discharge current must be controlled by specified value in Cell’s specification. Cut-off Voltage of discharging must be over 2.5V.

■ others Keep the battery away from babies and children

Section 1.2, Page 15, Sammysong 29E, https://cdn.shopify.com/s/files/1/0697/3395/files/29E.pdf?8108166701558616789

 

[flippy]

answer the question.

WHY does it say that in the datasheet?

(and no, you cannot find the answer in the datasheet)

 

[DogDipstick]

They did not test until "redline". They knew the power requirements ahead of production and designed the engine around this output, and the RPM to suit, with available manufacture process.

I dont know why you bring up engines with a heat engine builder. You do not seem to think I know anything about it, perhaps another attempt at proving me incorrect.

Trust me, we know when this engine will "blow up," without testing until red line. We cast every piece of that thing.. ( well, paid for the casting, SmokeyMountain CastingWorks some of those patterns cost 10K$ ea. Just for the pattern. Lol. ) We know the load, lifetime, and strength on these load paths, X Y Z.

Every little part was modeled and calculated to take the RPM @ the power output designed for. B4 it ever turned over once. Long before. It is a 40 RPM engine. I guess 41 rpm would be the "redline". Lol. We did not take the chance to make this ( half a million $) engine only to blow up at 30RPM... and we SURE AS HELL aint building an extra (engine) just to test the "redline".... and blow it up.. Half a million dollar... Our customer needed 40RPM, we made sure to design it to handle it. Without wasting a 400$K engine. First time. In a long time, you will see an engine like this. I do promise you that.

However, it can take at least double that RPM. We know this.. cause we build them, and know the mass, balance, distances, rates, orders, and vibrations created through the harmonics of the rotational masses on the load paths. Before it ever gets a single part cast, we knew this.

This pic was taken righ befor teh main conecting rod was fitted.

I know why I bring up battery questions with a battery-builder. Cause there is something that we all are collectively into, not fully educated upon, and wish for your input. The collective knowledge seems to disagree with you, Flip.

Collective knowledge seems to infer that the termination current is designed and suited to a specific cell, to be sold, by a certain manufacturer.

Not just there to be ignored... ? However, you seem to be saying it is irrelevant and can be ignored. Collective laymans knowledge disagrees with this. ( battery university ad the like)

answer the question.

WHY does it say that in the datasheet?

(and no, you cannot find the answer in the datasheet)

THAT IS WHAT im ASKING I DOT KNOW SO PLS TELL ME WHY!

 

[flippy]

The collective knowledge seems to disagree with you, Flip.

its just you and john.

answer the question. you had considerable time to google it, you should be able to come up with a decent answer by now.

if you dont know then why are you claiming to know how to read a datasheet?

 

[DogDipstick]

The collective knowledge seems to disagree with you, Flip.

its just you and john.

answer the question. you had considerable time to google it, you should be able to come up with a decent answer by now.

Battery University and John seem to dissagree. So does fatty. So do some others. The manufactures of many chargers disagree with you. ( such as the well kjnown Powerlabs and Ichargers From the googling and reading I can, and do, do.

ITERM - Definition:


Current C/? is a standard lithium type termination that stops the charge when the current is below a ratio set by the charge current. Typically Termination should be C/10.

Again: Collective knowledge seems to infer that the termination current is designed and suited to a specific cell, to be sold, by a certain manufacturer. Under warranty, and if these conditions are breached, no warranty. That is how I read it.

 

[flippy]

Battery University and John seem to dissagree. So does fatty. So do some others. The manufactures of many chargers disagree with you.

battery universtiy has not been relevant for 10 years now. neither care companies that sell chargers. they dont make chargers for a single model of cell. lets focus here on the subject shall we.

let me broaden the question and give you a clue with the question that you should be asking yourself if you read these specs:

what would it mean if the current has not dropped below 1/20C after the stated 3 hours with a standard charge of 1.375mA?
(no, the answer is not in the datasheet)

if you get this question right you are already halfway there.

 

[DogDipstick]

let me broaden the question and give you a clue with the question that you should be asking yourself if you read these specs:

what would it mean if the current has not dropped below 1/20C after the stated 3 hours with a standard charge of 1.375mA?

if you get this question right you are already halfway there.

Scenario
Charging from sub 4.2v..? it would continue to fill the cell with capacity until reaching an equilibrium, at 4.2.. where the CV stage would begin...

However, if it has reached 4.2v, and CV stage is in application, it takes me longer than the (3) hours to taper on some (large) cells. Current does not, has not dropped within 3 hours.

This is the scenario you present. Correct? I do run into this, on some cells, that are usually beat degraded, used, cells: Not reaching the specified termination current (set in charger) whithin the time period you mention.

Hypothesis: Cell is not full of capacity, and will be, if tapering is allowed to continue ( over your 3hrs). Until full, when the cells will be metered discharged and proven for the input capacity in mAh.

OR:

The current continues, never reaches C/20 as per your scenario.



, , and cell is heated slightly and lifespan is detriment. My hypothesis. The (loss) from the cells charge efficiency is greater than the current provided.. never reaching termination current taper for the cell,.... was never charged to full voltage.

Like the "overtapering" term I made up earlier,.... Some cells will benefit from a charge termination. If they are allowed to taper to minuscule amounts, they will have a detrimental lifespan for the long taper will heat the cell up in the long run.. This is my hypothesis.

I dont know haw a big vs small cell would react differently from this scenario, if any difference.

Small cells have high IR, and I suppose the heat created fro the collumbic in-efficency would be detrimental to the cell, moreso, with small currents, than a low IR large cell, with identical currents... .

Is that what it means? I honestly dont know what the specified "3hrs" has to do with it. I do not see any reference to the "3hrs" you refer to. Is that on the sheet? I will peruse again, for maybe I missed it.

3h or 0.02C

OK I see it now. I see it referenced.

Hypothesis:
that is so you don't hang it out on a taper indefinitely? Says it will reach one or the other, by mechanics, of process. So you dont hang a cell out on a trickling taper.. to terminate.. so the cell does not just sit there, full of SOC, but still creating heat through the current (waste)...? Healthy cells terminate and stop on the own. Unhealthy cells, with such a (low) termination current ( that may very well be wasted int he steel shell) may just continue to be warmed by the current as it is wasted... So the Man says " stop it after 3 hrs or this taper, whichever comes first" to cover their ass(et)s.

Am I close?


However, it* WILL reach that when the IR is raised at the end of the charge ( cell takes no more).

*(healthy cell with low, spot on IR, working as designed for that termination period)

I dont know.

I do not think you can call " Battery University" irrelevant as in "It is so 10 years ago".... Therefore disregarding.. their work, discussion, references, and following, as being not up to date... I would say your argument is invalid. I think, so would, the authors whom publish, there. Honestly.

Hell, they (the people, you know) been designing battery storage for 170+ years.. and that infor mations are VERY relevant still... and used e-v-e-r-y day with reliable applications, designed by said engineers.

I got storage battery engineering books from 1920 or earlier.. that have taught me more than you , and honestly, and that info is still 100% relevant today. .... The books published, today, hold the same information.

 

[DogDipstick]

I swear to GOD I will set up tw0 cells on 10 cycle tests, ...


2 sets.
Identical, right out of the batch, numbered one right after the other...Cells.
Identical chargers.
Identical length leads...
Identical temperatures of testing.
Identical computer reading both chargers.
Identical power supply for each channel.

I could even film it for later references. Side by side. To prove I am not doing any trickery.

At identical charge profiles save one thing.. the termination current...

One ( set of data) will be set to the C/C (C/1) termination current (corresponding TIME ).. ( id, charge with 15A, termination current will be 14.999A.. and as soon as the cell reaches this point the charge will stop)... 10 cycles on graph, with capacity time and charge current labeled.

One ( set of data) will be set to C/(datshet stipulation)... (C/10 or C/20 or whatever the sheet says... ) and cycled the same 10 times on those (two identical side by side) dataloggers. ( I charge at 15A, I terminate at C/10, 1.5A... ) ... 10 cycles on graph, with capacity time and charge current labeled.

We will see the capacity and trends in the charging profiles. Empirical. ON graph, next to each other, and able to run for repeatability X times. Time, Capacity, Current. 2 sets.

All you have to do is say "JP do it"... and then,... compare the (sets of) data, when it pops up on your computer screen tomorrow, when I post it. Then we can discuss what we see. Record the differences in the logs, labeled in regular ol numbers.

I do offer to do this if anyone is interested. Yall know i am equipped: It would be here tomorrow, the data. On this supercomputer,, shared.

I swear it.

I also wanted to say I can run this test with any final voltage choice... from 3.0v.. through 4.3v... On the graph. We could look for incongruencies.

 

[flippy]

Charging from sub 4.2v..? it would continue to fill the cell with capacity until reaching an equilibrium, at 4.2.. where the CV stage would begin...
However, if it has reached 4.2v, and CV stage is in application, it takes me longer than the (3) hours to taper on some (large) cells. Current does not, has not dropped within 3 hours.
This is the scenario you present. Correct? I do run into this, on some cells, that are usually beat degraded, used, cells: Not reaching the specified termination current (set in charger) whithin the time period you mention.

i asked for this specifc cell. not any others. lets keep it simple and focused.

Hypothesis: Cell is not full of capacity, and will be, if tapering is allowed to continue ( over your 3hrs). Until full, when the cells will be metered discharged and proven for the input capacity in mAh.

its not my 3 hours, its the datasheets stated 3 hours that a charge should take. the manufacturer has concluded that in their testing that if you charge the cell by its reference parameters (As stated in chapter 6 and 7) should it take longer then 3 hours to reach this state then the cell does not meet specifications. it does not say it is bad or worn, just that it does not meet the datasheet specifications. more on this below.

The current continues, never reaches C/20 as per your scenario.

the same thing applies as above. the cell no longer meets specifications as stated in the datasheet. it does not tell you anything more then that at this point.

and cell is heated slightly and lifespan is detriment. My hypothesis. The (loss) from the cells charge efficiency is greater than the current provided.. never reaching termination current taper for the cell,.... was never charged to full voltage. Is that what it means?

yes, mostly correct.
heating is a byproduct of any battery charge but heating does not mean bad things, many cells operate better at higher temperatures. this is why the datasheet mentions testing temnperature specifically in chapter 6. any testing done outside the range stated in the datasheet is invalid if you want to know the state of the cell. so far you only concluded that the cell has a high self discharge that exeeds the cells capacity to absorb current at that specific voltage. in order to make a assessment to understand what is going on you will need to do a charging and discharging test as stated in the datasheet of the cell.
but that datasheet only tells you the state of a NEW cell. not a used one.

Like the "overtapering" term I made up earlier,.... Some cells will benefit from a charge termination. If they are allowed to taper to minuscule amounts, they will have a detrimental lifespan for the long taper will heat the cell up in the long run.. This is my hypothesis.

"hypothesis" would be the correct word. that is a word you use when you dont know but have an idea. lets correct this and turn in into fact. but the "taper" is speak of is the CV portion of the charge so i will use that term. taper is just clouding the subject.

few ground rules we shall no longer debate and you will have to accept these as simple fact, if you dont understand these concepts you can ask for clarification on them if needed on how it exactly works:

1: the CV section of a charging process can happen at ANY voltage.
2: the voltage of the charging process is dictated by the charger/power source.
3: every single CC/CV charger/power source will NOT increase its voltage beyond what is set.
4: every single CC/CV charger/power source will NOT increase its current beyond what is set.

many cells (basically none) have a linear relationship between their float voltage and capacity. generally most capacity is between the 3.5 and 3.8 range. the higher you go beyond 4V or so you get less and less capacity relative to its voltage. so charging at lower voltages means it takes longer to saturate the cell at that voltage relative to charging at higher voltage. its basically like filling a colander but with less and less holes the further up you go. eventually the cell will ber actually filled. but this process will take many hours, especially on lower voltages where most of the capacity is. so even stopping at the 1/20C will take frocking ages if you do that at 3.8V for example.
so, the CV section is completly and utterly dependant on what the cell wants to do by the design of the chemistry. the charger has ZERO influience on the CV section. it only caps the current during the CC portion (hence the name) as the cell will abosrb all the currents it can in relation to its IR. so you need to protect the cell from itself during this stage. but once you reach your set voltage the current will naturally lower as the IR increases and the cell fills up to your set voltage (whatever that might be).

lets be clear: the cell does not give a frock about what voltage you charge it to. that is a lifespan/capacity question you need to make when making your product. lower is better in this regard. but you will need more cells to compensate for any consession you make in this regard wich will add cost and all that jazz. so lets stay away from that part as far as we can and just discuss that you can charge to different voltages. the reason behind it is not relevant for this moment.

you are VERY focused on the last bit of the charging process and stopping it there. lest see what happens when you do.

if a cell is not saturated at the voltage were it is being charged at (aka: still taking in current) it means that as soon as you cut the charge the voltage of the cell will drop. especially on a 4.2V charge level this drop can be quite noticable. 4.15V float or even a tad lower is not uncommon. this voltage WILL drop the more wear the cell has.
so what did you actually do by doing this? you charged the cell to 4.15V. not 4.2V. that is it. once you let the battery rest the voltage simply drops to its -actual- charge level.
so knowing this, why not just charge to 4.15V and just hold the cell there? for the cell it does not matter, its a 4.15V so nothing is different.

here is the important bit i think you misread in all this:
yes, there is some studies done in keeping the cell floating but these studies have shown that the damage that is being done is nothing compared to just charging to a high SoC. so if you were to charge a cell to 4.15V for example and kept it floating there will do the exact same "damage" to the cell as just charging to 4.2V and cutting the charge off a 1/20C as stated in the datasheet and the cell will drop back down to 4.15V anyway.
if i were to charge a cell to 4.05V and just hold it there it would do the same "damage" then charging to 4.1V and just cutting off the charge as the cell will naturally already drop down to 4.05V. so in the end you do the same thing, just with a lot more expensive tool.

I dont know haw a big vs small cell would react differently from this scenario, if any difference.

cell size is not a factor. its the chemstry that decides what happens.

Small cells have high IR, and I suppose the heat created fro the collumbic in-efficency would be detrimental to the cell, moreso, with small currents, than a low IR large cell, with identical currents... .

IR is a result of size and chemestry. there is a natural balance that dictate their use case. using a high IR laptop/phone battery in a cordless tool will yield "interesting" results. using low IR power tools in a phone will do as well, as you walk from charger to charger as the capacity is utter shit. its just a question of remaining within the specs and preferably under them. cooking any cell regardsless of its size is detrimental.

Is that what it means? I honestly dont know what the specified "3hrs" has to do with it.

hopfully you begin to understand that the 3 hours have nothing to do with normal operation/usage. just testing the cell according to the manufacuters specs.

However, it WILL reach that when the IR is raised at the end of the charge ( cell takes no more).

so the cell terminates the charging process naturally by itself without any input from the charger. you can just hook up a CC/CV supply to a cell and once the cell has reached its steady state at the set voltage nothing more will happen, just like communicating vessels do. at some point the level (voltage) is equal and nothing more will happen. it REALLY is that simple. so "terminating a charge" is completly unnessesary unless you are TESTING the cell.

ps: running those tests is fine, but several people here already have done a LOT more testing then you will probably ever do. i have litteraly spent over 10k euro in test equipment over the years and have tested hunderds of cells to their breaking point.
that is why i am telling you that terminating the charge does basically nothing you need to concern yourself about. just dial the voltage a tad down to 4.1V or so on your dumb CC/CV power supply and you will also enjoy a battery that will live a happy long life. at least one that lives longer then one you keep topped up tat 4.2V with your expensive charger...

 

[DogDipstick]

So you conclude. I hear what you assert, truly.... and do, will take it as knowledge, as we all will, here in this thread.

ps: running those tests is fine, but several people here already have done a LOT more testing then you will probably ever do. i have litteraly spent over 10k euro in test equipment over the years and have tested hunderds of cells to their breaking point.
that is why i am telling you that terminating the charge does basically nothing you need to concern yourself about. just dial the voltage a tad down to 4.1V or so on your dumb CC/CV power supply and you will also enjoy a battery that will live a happy long life. at least one that lives longer then one you keep topped up tat 4.2V with your expensive charger...

Man, I (litteraly) spent a good 1$K in the last year specifically on this ( cell testing) hobby of mine. Yeah I may not do "as much ever" testing as some.. It aint paying the bills.. Only as controlled as my amateur reasoning... is ..

but I'm doing alot, proficiently, and well. Much more than some others too. With reliable results.

Your work probably paid for your shit. Lol. I paid for my shit by myself.

Still, I wannsee a side-by side. For my own reasons. Cause I like this hobby.

 

[flippy]

Man, I (litteraly) spent a good 1$K in the last year specifically on this ( cell testing) hobby of mine. Yeah I may not do "as much ever" testing as some.. It aint paying the bills.. Only as controlled as my amateur reasoning... is ..
but I'm doing alot, proficiently, and well. Much more than some otherstoo. With reliable results.
Your work probably paid for your shit. Lol. I paid for my shit by myself.
Still, I wannsee a side-by side. For my own reasons. Cause I like this hobby.

no, i paid for it as a hobby and now i am making money with it. yeah, i spend a LOT on this crap.

but i am not really into the market for cute little ebike batteries. i dont really care unless its above 3kWh basically. its not worth it do make batteries under that.

but that small batteries is not my thing does not mean i cant help the people that do want to make them. and having made batteries above the 100kWh mark does give me some perspective on what does matter and what does not.

keeping a battery floating at 4.1V does not matter for example. the regular wear of just cycling it will wear it down a LOT harder then keeping it floating. it does not matter if that battery is 100Wh or 100kWh.


ps: if you want to do proper long term testing then make sure you have a UPS on your test equipment and have a UPS behind that one. and make sure the batteries are HUGE. doing months of testing with a american power gid is no fun.

also: get several lab power supplies. just the cheap ones from aliexpress that run off switchmode power supplies. dont bother with linear supplies on batteries. they dont care but it does save a LOT of power.

and keep those cells floating at 4.1V or whatever for months and see what happens compared to the one charged to 4.2V

ps: read the samsung 29E datasheet, page 10, chapter 2.2 and 2.3 :wink:

 

[Aerox]

I tried to read the topic as well as I could but many things were too complicated for me for now.

I bought 16 Lishen 3.2V, 272Ah lifepo4 cells to install in a RV.
I'm not sure yet to understand what would be the best wiring /battery topology in terms of possibilites/upgradability and cost? Taking into accoung alternator charging (12v output), solar charging via an mppt.

I was thinking of 2P8S, so a 24v system because I read that it had a few advantages. Smaller wire gauges, bigger inverter available etc.
There are equipment in the RV that need 12vDC (mainly the fridge, water pumps, lights and part of the diesel heating (glow plugs)).

My question related to this topic:
What would be the most modular/price/performance solution for:
- Fast "shore charging" using an AC to DC charger. 1500W+ (The idea being able to quickly charge my batteries from a EV charger or camping plug)
- Modular system (if I first want to wire the cells in 4S4P, later 16P for instance)

The cells are rated for 1C continous charging. My hypothesis is that charging at max 0.5C would optimize for lifetime and at the same time give me fast enough charge.

I've seen solution based on meanwell psus wired in parallel.
Like https://endless-sphere.com/forums/viewtopic.php?f=2&t=18598
But the topic I found were several years old.

Meanwell has many series : https://www.meanwell.com/productSeries.aspx

or just buy a meanwell ERP series if you want compact power with active cooling or a ELG/HLG if you want waterproof for mounting on the vehicle. it litteraly does not get better quallity then the ERP or HLG series. in the nearly a decade of using them i NEVER had a single one break or a customer come back for warranty. and i have mounted hundreds of them on vehicles.

Why is the ELG/HLG better suited than for instance the DRP series?
https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/DRP-3200/DRP-3200-spec.pdf

Or the RSP series
https://www.meanwell.com/webapp/product/search.aspx?prod=RSP-1600

It is because of features? Power/volume? Or easy access and price/perf ratio?

 

[flippy]

I tried to read the topic as well as I could but many things were too complicated for me for now.

dont bit off more then you can chew. one step at a time.

I bought 16 Lishen 3.2V, 272Ah lifepo4 cells to install in a RV.
I'm not sure yet to understand what would be the best wiring /battery topology in terms of possibilites/upgradability and cost? Taking into accoung alternator charging (12v output), solar charging via an mppt.
I was thinking of 2P8S, so a 24v system because I read that it had a few advantages. Smaller wire gauges, bigger inverter available etc.
There are equipment in the RV that need 12vDC (mainly the fridge, water pumps, lights and part of the diesel heating (glow plugs)).

higer voltage = better. less amps = less wire gauge, losses and voltage sag. you can buy up to 5kW inverters from aliexpress that run at 48V. lots of solar panels are around 50ish volts so do factor in you need to put them in series and get a suitable mppt controller. there are inverters with built in solar.
only cells in series will also help you check for bad cells MUCH sooner then when you put them in parralel. you also only require a simple balance board for this setup.

My question related to this topic:
What would be the most modular/price/performance solution for:
- Fast "shore charging" using an AC to DC charger. 1500W+ (The idea being able to quickly charge my batteries from a EV charger or camping plug)
- Modular system (if I first want to wire the cells in 4S4P, later 16P for instance)
The cells are rated for 1C continous charging. My hypothesis is that charging at max 0.5C would optimize for lifetime and at the same time give me fast enough charge.

you are not going to need to charge that fast. you can charge while driving if you want to and would be preferable, the engine is already running anyway. you can eiter add another alternator (american power systems make 56V alternators that can push 9kW or soemthing stupid like that, dont ask about the price tho) and use that to charge the pack. or just a normal 12>56V boost block to top up the inverter battery when the engine is running. i would not do more then 500W or so with a standard alternator. invest in good solar would be my first choice and yields the most profit in daily use. just cover every little bit of that roof with solar.

Why is the ELG/HLG better suited than for instance the DRP series?
https://www.meanwell-web.com/content/files/pdfs/productPdfs/MW/DRP-3200/DRP-3200-spec.pdf

ELG is the budget version of the HLG. cheaper case. lower effcientcy and some of that. the DRP does not qualify, it has not constant current mode.

i do NOT recommend using a ELG/HLG in soething like an RV. these things need outside air cooling. the HRP is a much more suitable series.

Or the RSP series
https://www.meanwell.com/webapp/product/search.aspx?prod=RSP-1600

again: no constant current mode.

It is because of features? Power/volume? Or easy access and price/perf ratio?

the most ovious choice would be the RST-5000-48. its 5kW output and constant current. you can even put them in parralel.
BUT that thing is 3 phase so you need to have a lower power single phase option if you run into just a normal shukko or "blue" camping plug. for that you need to put 2 HRP-600-36 in series in order to get the proper voltage. ps: you only need 15 of those blocks to get 58V peak wich is just under the limit of the 48V inverters and the 5kW unit can get to that voltage as well.

so, 1 big ass RST-5000-48 for fast charging at 5kW and 2 HRP600-36 (for 1.2kW of power) to charge the battery at a normal shukko without fear of popping anyones fuses or burning up someones extention lead. the shukko will be enough to charge from dead to full in 10ish hours or so., the 3 phase big boy can do the bulk charge in about 2 hours. on campings where you only get 6 amps this solution would be perfect as you an draw big currents from the pack and use the HRP to keep the battery topped up without popping the 6A fuse outside that many campings in europe have.
if you take these units and a 5kW inverter you can cram it all in a pretty compact place in the RV. also at a reasonable cost. (exept for the RST, that will cost you at least 1000 euro)

and ofcourse you can use a simple SD-500L-12 to have a 48V to 12V converter to drive any 12V stuff you might have. or even a SD-1000L-12 if you are feeling adventurous on the 12V department. and need to crank a car or something. :lol:


ps: i built a LOT of these setups already out of my company. its not extremely difficult but i did learn to stop using 24V. its not worth it comapred to the advantages of 48V.

 

[DogDipstick]

Last rv I worked on had 220v appliances.

Shore power was 220v or 110.

We installed ( 2 @7kw) 14 kw of inverters and 30 kwh of brand new lifepo (at 6800$. ).... @48v.

It still doesn't keep up with the AC for more than a day. Lol.