Regarding Pack design and naming convention

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cccerberus

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t-What-does-S-and-P-stand-for-What-is-Xs-Yp-or-XsYp-with-X-and-Y-being-numeric-digits

In the thread referenced above, certain naming conventions are laid out that (with all due respect) make not a lot of sense. I read through that thread, hoping to find some standardization of the naming but found it to be self contradictory, and only made things worse.

A resource i read elsewhere said that they always represent the X-Series value first because they are always connected in parallel first anyway (a la Tesla) which again makes no sense to me since i know of projects that went the other way entirely.

Now, I don't know if there is a higher order authority that decides these things, but i would propose that, given the potential complexity of battery pack configurations, that naming be done in a logical way. For instance, I know there is a group of people who are building 7 cell seriesboards, connected in parallel to whatever capacity they are looking for.

I would call this a 7S(whatever)P pack(or string or array).

Meanwhile Tesla in at least one of their vehiclesapparently does ~20 cells in parallel, connected in series to another ~20 cells in parallel and so on (lets say 10 times just for a number), inside a string of a 5 string pack for the vehicle.

I would call this 20P10S(5(?)) (unsure whether the strings are connected in parallel or in series or totally independent of each other)


To me this makes sense in that it is the most clearly descriptive way to describe the way it is designed.

Does this make sense to anyone else? or am I that guy?


Order makes a difference. A 4S3P isnotthe same as a 3P4S.
. - A 4S3P is 3cells in parallel, and then connected in series to make 4S.
. - A 3P4S is 4cells connected in series, then 3of these connected in parallel at the ends of the series strings.


specifically, this seems dead opposite of what it should be.
4S3P is 4 cells in series, each of those 4 cell series packs connected in parallel..

and 3P4S is 3 cells in parallel connected in series with 3 others to make 4 series clusters

right?
 
Hi ccerberus,

It makes sense, that's right. But if you write always the s first, as normal, you see at first what voltage the whole pack has, so for me this is better.

And I don't know why you should connect x cells in series and y packs of those in parallel, because this way you need y BMS's and if you connect y cells in parallel and x of those packs in serial you just need one BMS with y times the current.
 
If we were talking about baskets of pine cones, we'd say we have 3 baskets of 20 cones. So, that's be 3b20c. This is exactly the same way for the cell/pack designation. If we have 14 packs of 80 cells, we have 14s80p.
 
LEDSchlucker said:
Hi ccerberus,

It makes sense, that's right. But if you write always the s first, as normal, you see at first what voltage the whole pack has, so for me this is better.

And I don't know why you should connect x cells in series and y packs of those in parallel, because this way you need y BMS's and if you connect y cells in parallel and x of those packs in serial you just need one BMS with y times the current.

Wherever the S is, it would tell you the voltage ballpark, whether it was beginning, middle or end..

I agree that X cells in series and y packs in parallel is problematic for all the reasons you state, but the solution they had was to have a break out header on each board with a terminalfor each cell for balancing, then connect all those breakout headers with a ribbon cable. its a cool idea but then that is actually paralleling each 2nd cell, and each 3rd cell and each 4th cell etc.
And being a ribbon cable it can't handle any actual current, but it is used for balancing..
 
There is a technical sheet on how this should be said but we have not gotten our hands on it and it cost money. Until this electrical techsheet arrives in my hand the above is the correct naming :)
 
daromer said:
There is a technical sheet on how this should be said but we have not gotten our hands on it and it cost money.

Link to it ? - the paid for version please.
 
I dont remember the number of the document out of my head but see if I can look it up.
 
We have discussed this at length when putting this together, especially with regards to complexity for people new to the business. The problem is that the notation of XsYp does dictate what the final result is, but not necessarily the way to get there.

4s3p can be 4s+4s+4s / 4s x3 or 3p+3p+3p+3p / 3p x4 and both ways give you 4s3p if you have connections in between the cells. The 3p x4 is just easier to build and makes more sense. And under no circumstances it will give you 3p4s. The latter is rarely used anyway and you shouldn't make batteries like this unless you have a specific reason because there is no way to access specific cells unlike you can do in 4s3p configurations. You could argue that the difference between both notations is very small and you'd be right, but we can't rely on no one building 3p4s batteries so this has to be accounted for in some way. This adds more complexity to the subject but it can't just be ignored. The fact that you bring this up confirms this.
 
"officially" posting this attempt at a battery stringing convention, and its obvious ambiguity does appear to be at odds with the recently introduced "dont blame us" terms that we've all had to agree with before forum content access is granted.

Having to agree with "dont blame us" terms is a wise move - but it really doesn't make sense to be posting ambiguous data regarding a fairly critical component of a system.

I have access tostandards and conventions across most of the developed World, if anyone can point me to any officially recognised and approved naming or stringing nomenclature I'll produce a simplified version for possible use here - if, as it appears to bethe case with the introduction of the "dont blame us" signup, there are concerns about the content of this forum, it would be a wise move to stop trying to invent "standards", or at least ensure the total clarity of them before they are posted.
 
I'm not aware of any officially published standard on the subject. I'd be interested to have a look if daromer can find it again.

Apart from that, we don't invent a standard here. This is out in the wilds for years and even decades. People will have seen it or heard about it and will try to use it. We're trying to provide guidance on how to use the notations properly to make sure that everyone is talking about the same thing.
 
DarkRaven said:
We're trying to provide guidance on how to use the notations properly to make sure that everyone is talking about the same thing.

Good idea, butwhatever is posted, needs to be 100% unambiguous.
 
I have seen a standard that do have parts of it explaining the xsyp thingy.. And its opposite the way most users and companies do it like we have sticked to here.

I was given info about it but the guy in question refused to show me it since it was not an open thing and you had to pay for it... With that said I will look for it so you Sean can see if thats something you can get hold of.

I need to dig through a 1km long chat and maiklthreads since i dont remember the publication number of it...
 
Sean said:
DarkRaven said:
We're trying to provide guidance on how to use the notations properly to make sure that everyone is talking about the same thing.

Good idea, butwhatever is posted, needs to be 100% unambiguous.

I think this is unambiguous actually. There is a difference between inherent complexity and ambiguity. It is not as if something is ambiguous just because some people are not able to grasp the complexity of the whole concept on first try.

And let us be honest here, even if there is the one official standard, published by some kind of governing body, how much would it be worth? Standards are only as good as their adoption rate. If it is behind a paywall and unknown to the vast majority of people then you could also have no standard at all and it would not make a difference. If even we don't know about it, how is this going to reach someone new to the business? There are people starting to build their own batteries,barely able to understand what a lithium cell is and you try to tell them that the notation of how they are constructed used everywhere is wrong and it should be reversed. Good luck with that! :D

We have a de facto standard used for ages, if there is (or was) any interest in establishing a real standard it is too late now. For a standard to work you need a generally accepted governing body of some kind and official documentation of the standard, available to the public, which then everyone adopts. If you do not have this, and it seems we do not have either, then you will not have a standard that is worth anything.
 
DarkRaven said:
We have a de facto standard used for ages .....

Then anyattempts to document that de facto standard should be completelyunambiguous to everyone, not just you - as has been demonstrated, that's clearly not the case.
 
So 1 person is confused with the nomenclature and all of a sudden it's not an accepted standard and has become ambiguous. Gotcha!
 
Korishan said:
So 1 person is confused with the nomenclature and all of a sudden it's not an accepted standard and has become ambiguous. Gotcha!

Nope, one person has taken the time point out the ambiguous nature of what's been documented.

That's not the same as stating that one person is confused.
 
Sean said:
DarkRaven said:
We have a de facto standard used for ages .....

Then anyattempts to document that de facto standard should be completelyunambiguous to everyone, not just you - as has been demonstrated, that's clearly not the case.

Well, if you think that not understanding something is caused, causally, by it being ambiguous and that there is no other possibility why anyone could be confused about it, then this is another story entirely. And luckily it is yours alone.
 
Sean said:
Korishan said:
So 1 person is confused with the nomenclature and all of a sudden it's not an accepted standard and has become ambiguous. Gotcha!

Nope, one person has taken the time point out the ambiguous nature of what's been documented.

That's not the same as stating that one person is confused.

There have been plenty of people who have asked about this nomenclature in other sections. And in those replies many of us have said "Hey, check out the explanation in the FAQ <link>". They come back with "OHh! Thanks, makes a lot more sense now"

Sooooo, with that logic, it seems that the FAQ is doing it's job about helping people out to understand how and why the naming is done the way that it is. Again, if 1 person is confused about it, that doesn't make it ambiguous.

If there really were an issue with this subject, why are you just now making a big fuss about it. This has been in the FAQ for almost a year, if not longer. If there was an error in the way it was presented, discussed, explained, why wait till now to raise a ruckus over it. I think the common sense and logical thing would have been to raise a question about waaaay back then and then back it up with the reasons why you view it that way.

As it stands now, this has gone completely OT. And for those reasons, I'm closing this thread. When daromer is able to get this requested information about the datafile, he can post his results here, and maybe re-open this thread.
 
We picked this way of naming it in beginning because thats what 90% of the places name it as.

Standard or not thats the most common way to name it for now.
 
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