# LG Chem battery dissection



## mdrobnak (Mar 19, 2020)

My 60V modules are just cells with balance leads coming out to the connector. Looks like that PCB is a balance module. Probably needs a master of some sort, but you probably don't need the Orion, you need something like SimpBMS.


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## OR-Carl (Oct 6, 2018)

Haha, yeah, everyone likes pictures! So it seems like the way production EVs are generally built is to use a pcb on each module that is connected over CAN to a control board. My module boards were connected with a molex wiring harness, yours appear to be soldered in place. I am not familiar with the Simp BMS, but it would not surprise me that people have been working on a drop-in replacement for the control board on common batteries. However, at 475 british pounds, it is not really a budget solution, although it would be a bit cheaper than an Orion, I think. 

You can download the installation manual for the BMS you are thinking about using and look over how they are wired. Then take a multimeter and figure out how the cells within the module are wired, and where that voltage shows up on the board. It might route to one of those output connectors. If it does, your BMS can connect there, or else you will need to solder wires into those big connections to give the bms a spot to monitor each cell. The instruction manual should make it a lot more clear.


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## mdrobnak (Mar 19, 2020)

If you want to just do balancing, you can run it on a Teensy 3.2, just need to get it stable power. The code is open source.  So it depends on how much people want to do. Mostly PnP, buy the kit (I did) and it is pretty simple and works reasonably well...controls my charger, etc.

-Matt


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## Megatron451 (Oct 9, 2020)

Thank you for all the responses. Sounds like there are a couple directions that people would take with these. I need to do some more probing to hopefully find some points on pins that I can get all 12 cell voltages from, if not, I'll probably just have to run wires straight from the cells, which would suck.

I'm kinds stuck on the Orion because I already have the Orion 168 (without the cables though), so I'll probably just keep trying to use that.


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## angusmf (Jul 20, 2020)

Ignoring the management stuff, how possible does it look to disassemble these and make something like a 60 or 72V module?


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## Megatron451 (Oct 9, 2020)

angusmf said:


> Ignoring the management stuff, how possible does it look to disassemble these and make something like a 60 or 72V module?


You could do it, but there isn't really an easy way to hookup BMS, probably better off finding the 60.8V versions of this if that is what you are looking for.


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## angusmf (Jul 20, 2020)

Megatron451 said:


> You could do it, but there isn't really an easy way to hookup BMS, probably better off finding the 60.8V versions of this if that is what you are looking for.


Thanks, good to know. For what I'm doing, removing the OG BMS and soldering or welding on some leads would be reasonable. For the 60-72V scenario, I'm hoping it would only need one or two of these to deliver 500A for reasonably short bursts.

Hope you figure out something on the BMS tho. It would be nice to use a stack of these in a larger EV project also.


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## OR-Carl (Oct 6, 2018)

Megatron451 said:


> I'll probably just have to run wires straight from the cells, which would suck.


I dont think it would be that bad. Seems to me you have 2 decent options:








Either solder a wire into the power connection for the PCB (red) or drill and tap the aluminum plates on the actual cells themselves (orange). The BMS connection does not have to be beefy, it can be made with 20 gauge wire. Its a little hard to tell just exactly how big those soldered connections are, you might need a decently sized iron to melt that much solder.


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## Megatron451 (Oct 9, 2020)

I really appreciate your response to this. The red circles actually didn't show voltages on my multimeter when testing them, I also assumed they would have the voltages of the cells. I might have to do your second option. But in the next couple of days I'll just go back through with my multimeter and set the black lead on the negative of the battery, and just go around every little connection I can find with the red lead of the multimeter and see if I can find anything.

I'd like to use the thermisters if possible, but I'm not sure where the connections are for those and how to tell what range they are. I "assume" if I can find the wire, it is a resistance wire compared to ground?


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## brian_ (Feb 7, 2017)

OR-Carl said:


> I dont think it would be that bad. Seems to me you have 2 decent options:
> 
> 
> 
> ...


Those don't look like aluminum plates - they look like copper bars with the cell tabs folded over them and welded together. Any terminal should probably be attached to the exposed end of the copper, not the tabs.

Also, as the text moulded into the case end frame suggests, this is the rear of the module; the front (opposite end) will have seven more similar bars, with the end ones connecting to the module's terminals. The BMS will need to tap into all 13 locations. The front is shown in the photos with the orange covers in place and the terminal posts protruding. The disconnected ribbon cables visible at each side presumably go the printed circuit board at the front.


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## OR-Carl (Oct 6, 2018)

brian_ said:


> Those don't look like aluminum plates - they look like copper bars with the cell tabs folded over them and welded together.


I am not an expert, but I thought those welds look like friction stir welds, which made me think they would have exposed the underlying copper if those tabs were made of plated material. But that was just a guess. 

Looking at this picture again, and I feel like we are missing something obvious. I also assumed we were looking at the back of the module, but now that I think about it, I do not see that the cells are actually wired in series... This would explain why there was no voltage - you might be measuring cells that are not connected anymore! I am starting to suspect that there must be interconnections on the reverse side of the orange cover plates? Can you post a picture of the front and back of the exposed modules, plus the inside of the cover plates? That would be a clever design, because as soon as you take off the cover, you break the circuit and reduce the voltages. Remove both covers, and you have 6 isolated cells, which would only read voltage from opposite ends. Does that make sense?

As for the BMS taps, Brian, wouldnt you need 7 connections for a 6 cell module? It is true that you will need one tap from the far side, but it has the terminal stud that can serve as the connection point, right?


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## brian_ (Feb 7, 2017)

OR-Carl said:


> I am not an expert, but I thought those welds look like friction stir welds, which made me think they would have exposed the underlying copper if those tabs were made of plated material. But that was just a guess.


No, the friction welds used in battery connections typically just join the materials where they touch each other, like a traditional electric spot weld; they're not friction stir welds that mix the materials to a substantial depth. Look at the tiny wires that attach each end of each 18650 or 2170 cell in Tesla module to the aluminum bus plate - it looks like the wire has been smashed onto the bus plate and stuck there. Anyway, this module is similar to any other LG Chem module of pouch cells, so the people who have worked with them at the cell connection level can confirm how the welds work.



OR-Carl said:


> Looking at this picture again, and I feel like we are missing something obvious. I also assumed we were looking at the back of the module, but now that I think about it, I do not see that the cells are actually wired in series... This would explain why there was no voltage - you might be measuring cells that are not connected anymore! I am starting to suspect that there must be interconnections on the reverse side of the orange cover plates? Can you post a picture of the front and back of the exposed modules, plus the inside of the cover plates?


Yes, they're wired in series. Each of those visible connections is presumably the positive tab of one cell (one one side of the copper bar) connected to the negative tab of the next cell, supported and located (and connected to the BMS) by the copper bar. There are 12 cells in series, so there are module positive, module negative, and 11 inter-cell connections... there appear to be six here on the back and so the the other seven (module positive, module negative, and 5 inter-cell) must be on the front.

The feature which makes this module look unusual - which threw me at first - is that the cells have one tab (terminal) on each end. Pouch cells more commonly have both tabs on the same end, each less than half the cell width, so connections in those modules alternate side to side as the current flow path works its way from one end of the stack to the other.

I can only guess that the soldered points have no voltage relative to anywhere because they are some sort of isolated intermediate point in the monitoring circuit for each cell.

But yes, photos of the front and back, both with covers removed, would make everything more clear.



OR-Carl said:


> As for the BMS taps, Brian, wouldnt you need 7 connections for a 6 cell module? It is true that you will need one tap from the far side, but it has the terminal stud that can serve as the connection point, right?


These are 12S (not 6S) modules, so you do need 13 BMS connections, 7 of which (including the two terminal studs) are on the other (front) side.

Here's a text drawing attempt to represent what appears to be the module configuration:

< Front Back >
(+)--[+ cell 12 -]__
/----[- cell 11 +]-/
\----[+ cell 10 -]__
/----[- cell 9 +]-/
\----[+ cell 8 -]__
/----[- cell 7 +]-/
\----[+ cell 6 -]__
/----[- cell 5 +]-/
\----[+ cell 4 -]__
/----[- cell 3 +]-/
\----[+ cell 2 -]__
(-)--[- cell 1 +]-/


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## OR-Carl (Oct 6, 2018)

Sure enough, it says 12s on the first post in this thread , I had forgotten that this is a 44 volt module... Disregard my previous speculation...



brian_ said:


> I can only guess that the soldered points have no voltage relative to anywhere because they are some sort of isolated intermediate point in the monitoring circuit for each cell.


If they are monitoring voltage, though, then they should show voltage relative to somewhere, right? If those solder joints show no voltage relative to each other, then they must not be connected to the copper bars that hold all the cell tabs. I am not sure what purpose they would serve in that case. I assume the OP verified that there was voltage between the sets of tabs/copper bars? At any rate, hopefully more pictures and an update will make things clearer.


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## Megatron451 (Oct 9, 2020)

so the two connectors that connect to the battery ballencer board have all the voltages needed for my BMS. Does anybody know how to source connectors? I was a digikey for an hour and couldn't really get anywhere.


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## OR-Carl (Oct 6, 2018)

That last photo you posted is the back of what I am going to call Board B, right? It mounts on top of Board A with 3x bolts above, 2x in the slots next to those weird connectors (6), and also holds the ribbons marked 4 and 5?

That appears to be more of a 2 part socket than a wiring harness. The two bolts on each side are likely what is holding it together. Also, if Brian is correct (and he usually is) then some of the cell taps are being routed through those ribbons, and so those signals would be lost if you remove board B? 

I see a lot of clear goop on those circuit boards, but did they by any chance not cover the back sides of those sockets? (i.e. the solder points visible at 6 on board B?) You could solder your wires to there if they show the voltages. It seems like you are keeping an awful lot of unknown circuitry, but I dont see how you would get all the voltages otherwise on account of those ribbons. 

If it was me, I would be tempted to think about ditching the PCBs entirely and trying to make a mechanical connection to those copper bars or aluminum/silverish tabs. Your BMS would have to route wires to the front and the back of each module. I suspect those BMS boards would not be a problem, per se; they probably are designed to not draw meaningful amounts of power from the pack, but they will be serving no function for you if you keep them.


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## Megatron451 (Oct 9, 2020)

I appreciate the conversation about this. So I am going to call board b the battery balancing board, I assume it is only to use resistors to make sure all the batteries are about the same voltages. I pinned out #1 to see if there were any voltages, but there were not, it is only an 8 pin connector, so I wouldn't have the 12 voltages needed plus ground.

I think #4 and #5 are either some type of pressure sensors or the thermisters, either way I don't know enough about those technologies to use those. 

#6 is what I am most interested. Those two black connectors have all the voltages needed for my BMS. They are two 8 pin connectors that connect to the back of board B. If I can't get anywhere with sourcing the connectors, I might just de-solder the connectors from the back of board B and run wires to the orion BMS that way.

Pictures below are removing the first plastic on the back side of the battery to get to the board B. It is held in by 5 screws.


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## OR-Carl (Oct 6, 2018)

Megatron451 said:


> I am going to call board b the battery balancing board, I assume it is only to use resistors to make sure all the batteries are about the same voltages. I pinned out #1 to see if there were any voltages, but there were not, it is only an 8 pin connector, so I wouldn't have the 12 voltages needed plus ground.


Yeah, I think you are on the right track. The outgoing harness (1) is probably connecting all the modules to a CAN bus, so it would not need to pass the voltages; it would just send data. 

I see now that there are 3 ribbons, so the center one must carry the voltages from the front (I am at this point clearly not the Shelock Holmes of batteries, but it is fun trying to figure out how it works ). Desoldering the connectors - or just soldering wires to the tabs - seems like it would be a simple and efffective solution.



Megatron451 said:


> or the thermisters, either way I don't know enough about those technologies to use those


Thermistors are pretty easy to identify - they will be a pair of wires that read somewhere around 20k ohms across them. The exact value will depend on ambient temperature, and they do come in different ranges, I believe, but I think 20k is a pretty common value. 

Do these battery modules have liquid cooling? Is that what the plug is on the left side?


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## Megatron451 (Oct 9, 2020)

OR-Carl said:


> Thermistors are pretty easy to identify - they will be a pair of wires that read somewhere around 20k ohms across them. The exact value will depend on ambient temperature, and they do come in different ranges, I believe, but I think 20k is a pretty common value.


I'll check voltages against ground first, if no voltages, mabe I'll get brave and try some resistance measurements across the side ribbon cables and see if that is what they are.




OR-Carl said:


> Do these battery modules have liquid cooling? Is that what the plug is on the left side?


Hmm, which plug might you be referring to? There isn't internal cooling, like it's 60.8V LG Chem big brother, I'll need cooling plates on the bottom.


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## OR-Carl (Oct 6, 2018)

I was looking at this:








but going back and looking at it again, it seems to be the protruding end of a bolt, not a plug.


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## Megatron451 (Oct 9, 2020)

OR-Carl said:


> I was looking at this:
> 
> 
> 
> ...


Ah yes, it is a bolt with a nut on the end. Kind of a funny place for one.


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## Megatron451 (Oct 9, 2020)

Adding on to this. Looks like the side flex ribbon cables show 11.5K Ohms when measured with my multimeter. Looks like four thermisters per battery. I am ordering the flat 5 pin (center isn't used) connector. So I think I have all the connections needed for BMS including thermal. Now to waiting for connectors to come in, the I can try out the Orion BMS. And I know to double, tripple, and quadurple check the wiring harnesses before plugging them into the orion.


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## joekitch (Sep 13, 2013)

checking in on this to see if you've found anything interesting
i'll likely be using these for my conversion


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## remy_martian (Feb 4, 2019)

What are you planning to use for a cooling plate?


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## joekitch (Sep 13, 2013)

making a cooling plate by getting a sheet of aluminum and getting routes carved into it isn't too difficult
and when possible he could re-use the stock chill plate
there are shops that'll make custom plates for you but tend to want huge orders and charge a fortune for the service


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## remy_martian (Feb 4, 2019)

Getting routes carved is the easy part. Not having it leak with 600 pounds of battery on them is the trick.


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## Megatron451 (Oct 9, 2020)

joekitch said:


> checking in on this to see if you've found anything interesting
> i'll likely be using these for my conversion


Sorry for my late response on this. I haven't really gotten very far to getting the car moving, but, I plan to get a lot done during my holiday break. I successfully wired to each cell on each battery, I can see each cell through my Orion BMS, still a little nervous about charging the batteries, but I'll definitely dive into that some more during the break.

For the basic functional setup, I am not going to run cooling plates. I am trying to leave as much room as possible to make changes to my system as I plan to learn a lot during the build. The plan is to get it all wired up and hopefully functioning correctly, and then go back and see what needs to be changed or improved. I don't think 8 of these batteries in series is going to get me very far, but they will definitely help me get started.


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## joekitch (Sep 13, 2013)

reading through this again....i assumed i could slap any orion BMS on top of these and it'd just work but is that a fool's expectation? does the battery internally really want a specific LG chem master or something and orion wouldnt know how to wrangle these?
i mean, i see the connector on the side of the assembled battery and i assume all the pins are for each cell plus maybe a common ground or something, and an Orion can handle all the fiddly bits?

my plan is to do dc fast charging on my build so a very watchful bms is key


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## joekitch (Sep 13, 2013)

8 in series puts you at 480 volts nominal, isn't that insanely overkill? 
but i guess if you only have 8, you can't really split them into any kind of configuration that gets you ~350 nominal without losing batteries. 6 in series is pretty perfect for most applications but yeah, you have 2 left over


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## remy_martian (Feb 4, 2019)

DC fast charging is ambitious. A good goal, but is not falling off a log. Are you sure you need it? 

I got by for a year on a 120V extension cord with the Bolt EV...the only reason I went with 240V/32A charging was I participated in a utility load-shedding experiment and got the EVSE for free. I've never needed the fast turnaround it provides and the car's DCFC is only used on trips....maybe half a dozen times over two years and I had other vehicle options available for those trips. I can see if you live in an apartment ir condo where there's no place to plug in, but you're obviously not in that predicament if you have a place to do the build.

A lot of thermal management/engineering. Added weight. More things to fail. Ask yourself if you're brave enough to take a homebuilt past towtruck radius and why you need it apart from bragging rights. Ultimately, builder's choice - I'm just provoking thinking here.


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## joekitch (Sep 13, 2013)

yeah these guys are the plate cooling type, electric supercar uses them and needed cooling plate





my big concern is how expensive cooling plates may be for really exotic packaging like on my project


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## joekitch (Sep 13, 2013)

remy_martian said:


> A lot of thermal management/engineering. Added weight. More things to fail. Ask yourself if you're brave enough to take a homebuilt past towtruck radius and why you need it apart from bragging rights. Ultimately, builder's choice - I'm just provoking thinking here.


major design ethos for my build is keeping weight in check at the cost of range, but making up for terrible range with fast charging
part of the reason i want to use these lg chem batteries, they have a ton of power density and wont get that toasty from fast charging, and i can cool the SHIT out of these things with active refrigeration in the cooling line. It's more work than normal liquid cooling (which you absolutely should use, air cooling is very bad) but not THAT much extra work.

the big limitation right now is that orionBMS and AEMEV are coming out with fast charge bms solutions but it isnt clear when those will drop


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## remy_martian (Feb 4, 2019)

Don't forget that in most LG setups, only one face of the cell is getting cooled, so I'd back off and say you could cool the piss out of them, but shit I'm not so sure.

The charging heat energy has to go through the thickness of a cell, worst case, then conduct through plates, then it hits your LN2-dewar-chilled coolant 😂 Unless you rebuilt the module to have both cell faces cooled, which I doubt.

That said, the Mach-E pulls it off (vs Bolt), so maybe...


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## joekitch (Sep 13, 2013)

those chill plates are surprisingly good at shucking away heat, but i imagine the key is keeping that cooling fluid nice and cold so its scavenging every bit of heat it sees


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## Megatron451 (Oct 9, 2020)

joekitch said:


> reading through this again....i assumed i could slap any Orion BMS on top of these and it'd just work but is that a fool's expectation? does the battery internally really want a specific LG chem master or something and Orion wouldn't know how to wrangle these?
> i mean, i see the connector on the side of the assembled battery and i assume all the pins are for each cell plus maybe a common ground or something, and an Orion can handle all the fiddly bits?


If you have the exact same batteries as mine, you'll need to open up both sides of the battery and manually wire to each cell. Orion BMS is one of the best ways to go with this as they give you one of the most complete managements systems. I am no expert on the Orion BMS units (yet), but you do have full control of when and how much to charge and discharge goes into the batteries, and I spend all day looking at each cell when they charge, discharge and balance to try to figure out the best settings.


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## brian_ (Feb 7, 2017)

joekitch said:


> reading through this again....i assumed i could slap any orion BMS on top of these and it'd just work but is that a fool's expectation? does the battery internally really want a specific LG chem master or something and orion wouldnt know how to wrangle these?
> i mean, i see the connector on the side of the assembled battery and i assume all the pins are for each cell plus maybe a common ground or something, and an Orion can handle all the fiddly bits?


There are active components in the module. If you want to bypass them to use a BMS not specific to the modules, you could bring wires out from the tap points to a connector, as Megatron451 explained.
_Edit_: I was thinking of the Ford Mach-E modules (similarly constructed to the LG Chem modules for the Chrysler Pacifica) with the active components for BMS in the module.

Someone would certainly need to work through the details of the "fiddly bits" to determine if some configuration of the Orion system would work.


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## joekitch (Sep 13, 2013)

actually, im a fool, this question is already kind of answered by electric supercar, and he seems to plug directly into those stock plugs
BMS Wiring Part 1 - YouTube


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## joekitch (Sep 13, 2013)

Hmm, would it be really infeasible to crack these open and rewire them internally to be 2p8s instead of 16s? That way the outgoing cell taps needed are 9 instead of 13, with each p cell acting as one

I'm thinking that may be necessary for my particular chosen bms to work


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## brian_ (Feb 7, 2017)

joekitch said:


> Hmm, would it be really infeasible to crack these open and rewire them internally to be 2p8s instead of 16s? That way the outgoing cell taps needed are 9 instead of 13, with each p cell acting as one


Pouch-cell modules of the style offered by LG Chem have certainly been reconfigured, but it is not trivial because the cell tabs are typically welded to each other and/or to tie plates, and the cells are oriented to facilitate the original configuration. They are not easy to disconnect, once they are you don't have an intact tab to make the new connection, and some (mostly likely most) of the cells will need to be removed and turned around to match the new configuration. If you're lucky, the cells won't be glued to anything that would cause a problem for the ones to be turned around.


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## joekitch (Sep 13, 2013)

I was able to get a hold of EV west for more info on their pikes peak car, trying to figure out how they get around the long parallel strings problem with their LG chem modules.

Unfortunately I don't quite understand what it is they're doing, but here's how they describe it

_Yes, our car is 2P6S. You can parallel modules if the cells are also in parallel with the paralleled module. Orion's fear isn't false, just a bit misguided as they don't differentiate parallel at the cell level vs. at the module level._

Hmm, parallel at the cell level...did you guys crack open those LG chem modules and make them parallel internally then? I thought they were 16s internally

_Yes, we have manufactured wire harnesses and PCB boards to be able to wire them in this configuration._

So instead of 16s at the cell level you guys rewired them to be something like 2p8s?

_We keep them 16S._

so now I'm confused because it sounds like they parallel at the cell level but they dont? Or they do, but only by changing a pcb a harness


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## Megatron451 (Oct 9, 2020)

I'll take a guess here and say they left the internals of the battery 16S, but then used 12 of those batteries to make the 2P6S.


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## joekitch (Sep 13, 2013)

digikey scheme it to the rescue

ok so the concerns about long parallel strings is essentially this, 2p6s, but its two 6s strings in parallel










so the question is, does ev west literally just do this instead? 6 paralell strings of 2s? assuming this diagram is wired correctly for that










although i wonder what ev west meant by custom PCBs and harnesses for that


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## brian_ (Feb 7, 2017)

joekitch said:


> I was able to get a hold of EV west for more info on their pikes peak car, trying to figure out how they get around the long parallel strings problem with their LG chem modules.
> 
> Unfortunately I don't quite understand what it is they're doing, but here's how they describe it
> 
> ...


They appear to have connected each cell of the module in parallel with a corresponding cell of a parallel module by connecting their BMS tap wires, without changing the connections which actually carry the charge and discharge current. If everything stays in perfect balance, the cell tap wires never conduct any current; hopefully the cells connected this way don't get far enough out of balance to cause too much current to flow through these small balance wires.


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## joekitch (Sep 13, 2013)

Also, Bisi's K3v uses these lg modules
from him, he has two separate 6s battery boxes with an orion BMS on each one. one's a master and the other is a slave.
on startup, they check against eachother's total voltages and if they DIFFER by more than 3v then they will NOT handshake and essentially it'll ignore the slave box and tell you to get home and charge on just the master box
seems like an interesting way to sort of force top balancing
although this is a relatively rare occurrence, according to him, the battery packs only desync if the car sits unplugged for like 3 weeks or so, which is pretty reasonable to me

he uses 96 cell taps per battery box though, and a 96 cell orion bms is $1225, wew.


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## joekitch (Sep 13, 2013)

Ok so, I just got a module which I'm pretty sure is the real deal and not something similar looking but different. This is from that vendor that's been posted around, hopefully LG doesn't find them and c&d them


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## gesso (6 mo ago)

32kW of used cell goodness. Suspect these came from at least 3 different minivans given the voltages...
I've been searching for aluminum tube extrusion to use as a cool plate, but so far only a place that will sell me 1000kg worth, lol.


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## joekitch (Sep 13, 2013)

Use as a cool plate in what sense?
Do you mean, aluminum tubes that you lay inside a cnc'd aluminum channel and compress to make your chill plates? I thought those were almost always made with copper tubing though


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## gesso (6 mo ago)

joekitch said:


> Use as a cool plate in what sense?
> Do you mean, aluminum tubes that you lay inside a cnc'd aluminum channel and compress to make your chill plates? I thought those were almost always made with copper tubing though


Something like this to place on the cold side of the batteries. Weld end caps on with hose fittings.


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## joekitch (Sep 13, 2013)

Oh, interesting design although the flow rate may be kinda bad, as all that liquid has to make a 90 degree turn and get all clumped up


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## remy_martian (Feb 4, 2019)

There's a manifold welded onto each end, so no 90 degree turns.


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## joekitch (Sep 13, 2013)

Does there exist a good balance charger/tester that'll work with these modules? Trying to find something that'll do the 16s these guys have, using the BMS leads, so I can hook them up one a time and make sure all the cells are good and get them all to a comfortable 80% storage charge, balanced


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## piotrsko (Dec 9, 2007)

Slow charge can be anything that stops at a precise voltage. Fast charge gets tricky. I know people that used toy RC balance chargers over a month.


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## gesso (6 mo ago)

This is my current setup, not amazing, but seems functional so far.

67.2V 3A Li-ion charger: www.amazon.com/gp/product/B07QZWHX9R
16s "BMS": www.amazon.com/gp/product/B07X367L4P
Battery meter: www.amazon.com/gp/product/B097BQV5HM
(I'm sure these can all be had cheaper and or better, but Amazon was the easy button for me for now)

The EV west BMS pin out guide(BMS Schematic Sheet) for these modules was correct for me, but it's always a good idea to double check.

The battery meter and BMS both use JST for connectors, so if you pick up some JST crimp pins and a crimper, it's pretty easy (though tedious) to set this up. I also removed the XLR plug from the charger and swapped to XT-60 as I like them better, but that's optional.


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## joekitch (Sep 13, 2013)

Completely forgot that these modules have their BMS pinouts weirdly split between the two plugs instead of combined

Also I'm wondering if there exists a more all-in-one battery checker and charger solution out there, perhaps 16s is too much for most of these systems


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## gesso (6 mo ago)

joekitch said:


> Completely forgot that these modules have their BMS pinouts weirdly split between the two plugs instead of combined


Yeah, it's a little annoying for wiring.
Also I'm very likely going to need to stand the modules vertically for packaging reasons and the connector + wire relief adds about an inch


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## joekitch (Sep 13, 2013)

Eh, having breathing room around the modules is good to have anyway, makes for easy wire routing, also servicing


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## joekitch (Sep 13, 2013)

Gonna show my ignorance here but could one get two of some 8s balance charger and basically have two of these running next to each other each charging half the pack?

Like, two of these

ISDT BattGo BG-8S Battery Meter, LCD Display Digital Battery Capacity Checker Battery Balancer Battery Tester for LiPo/Life/Li-ion/NiMH/Nicd https://a.co/d/0eQpaV7


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## floydr (Jun 21, 2021)

Another option
ISDT X16








ISDT X16 Dual Channel 2200W 20A 16S UAV AC DC Battery Charger


Specification: Input voltage: AC 100~240V Output voltage: DC 10~72V Charging current: 1.0~20.0A ×2 Discharging current: 0.5~3.0A ×2 Max. charging power: 1100W ×2 Max. discharging power: 50W ×2 Balance current: 1.5A/Cell Supported battery types and cell count: LiFe，LiPo，LiHv，LiHv (2~16S) Abnormal...




www.buddyrc.com




later floyd
a bit expensive over $600.


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## gesso (6 mo ago)

Yes and No.


joekitch said:


> could one get two of some 8s balance charger and basically have two of these running next to each other each charging half the pack?


Yes and No...

You could definitely connect an 8s balancer to each half of the pack, but you could end up with a pack that has one half balanced to a different SoC than the other half.

For charging you would either:
- Run a single 60v charger for the whole module (and have no easy way to cut of the charge when both halves are fully charged, as once the first half is charged the balancer wont know that there is another half that is still charging)
or
- Run an 8s charger per half, but there is no easily accessible (that I know of) high current tap at the 8s break in the module, so all your charge current for both chargers would be running through the 8th cell's positive balance line...


I'm sure there is some way to make it work, but it seems like it would be kludgy


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## joekitch (Sep 13, 2013)

I do wonder if something like this would work better. More expensive but double the charge amps

VNSZNR LiFePO4 BMS 48V 16S 100A Smart PCB Battery Protection Board Battery Management System with Balance Leads Wires and Wireless Module for Lithium Iron Phosphate https://a.co/d/4QDt81r


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## remy_martian (Feb 4, 2019)

It only allows a discharge rate of 200amps...


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## floydr (Jun 21, 2021)

joekitch said:


> LiFePO4 BMS


wrong chemisty BMS.
The chemistry of the Cells is NMC I believe, LG doesn't make LiFePO4 modules afaik. Check the balance current most likely only 30mA. 



joekitch said:


> Also I'm wondering if there exists a more all-in-one battery checker and charger solution out there, perhaps 16s is too much for most of these systems


yes the ISDT X16, there are others probably less expensive ones as clones and low volume makes are sure to arrive on the scene.
Later floyd


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## joekitch (Sep 13, 2013)

Isdt x16 doesn't mention NMC anywhere in it's documentation unless they're using a synonym I don't recognize


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## floydr (Jun 21, 2021)

lithium-ion chemistry--Nickel Manganese Cobalt (NMC) it is a 3.7V nominal cell with a max voltage of 4.2V and a low voltage cut off of 2.8V
MOST EV batteries are made of some formulation of Nickel Manganese Cobalt except for Tesla which uses NCA or LFP
It mentions LiPo,Li-ion which covers NMC. If it can charge Li-ion cells it can charge NMC cells
It doesn't meant any chemistry by chemical formula except for LiFe(short for LiFePO4) the others mentioned are generic terms
Later floyd


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## joekitch (Sep 13, 2013)

Ah, that makes more sense as to why I was seeing NMC mentioned so little

Also, these active balancers get a lot of mixed reviews, it sounds like they work fine as long as your module isn't -too- unbalanced

Cywhrvzsf 16S 5A 12S 14S Active Equalizer 13S 15S Whole Group Balancer Lifepo4 Lipo Lto Lithium Active Battery Energy Transfer Equalization Capacitor 12S 16S https://a.co/d/6YPspFh


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## brian_ (Feb 7, 2017)

joekitch said:


> Isdt x16 doesn't mention NMC anywhere in it's documentation unless they're using a synonym I don't recognize


"LoPo/LiHV/LiFe/Li-Ion/ULiHV"
What a mis-mash of nonsense. 

"LiPo" means lithium with polymer electrolyte, which means nothing about charging voltage or balancing
"LiHV" and "ULiHV" mean something to them... but who knows what
"LiFe" is nonsense but presumably means LiFePO4
"Li-Ion (normally "Li-ion") means any lithium-ion cell, which would include LiFePO4... but they could mean anything
They probably mean any type of lithium-ion cell, with some configurable parameters for at least voltage.


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## gesso (6 mo ago)

Now accepting suggestions for good heat shrink for busbars


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## joekitch (Sep 13, 2013)

Oh, tip from mrmoparman of Electrolite fame, use aluminum bus bars (although calculate how much thicker they need to be), they're far cheaper that copper


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## piotrsko (Dec 9, 2007)

Not a fan of aluminum, it flexes and corrodes, then work hardens. But yeah it's 1/3 the price of copper.


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## remy_martian (Feb 4, 2019)

^^ Aluminum is a total PITA to make and maintain an electrical connection to.


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## joekitch (Sep 13, 2013)

I never see anything about these little two pin plugs on either end of the batteries. What exactly do these do?


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## gesso (6 mo ago)

Thermistor connections I believe. I'm 90% sure they just loop back to the 12/16 pin connectors.


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## joekitch (Sep 13, 2013)

that would explain why i was getting nada on the thermistor pins
i got a 30 pin terminal block coming in that i'll throw the stock harnesses on, which will let me read cell voltages from my volt meter quite fast, and the thermistors can hang out on there too


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## joekitch (Sep 13, 2013)

oh and relevant for this thread, they're back in stock at ev west, they found a new supplier 


LG CHEM Lithium Ion Battery - 60.8V, 2.6kWh, EV West - Electric Vehicle Parts, Components, EVSE Charging Stations, Electric Car Conversion Kits


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## joekitch (Sep 13, 2013)

so, uh, don't buy from tech direct club
turns out two of my modules have a few bad cells, but TDC won't do any replacement unless a cell is more than 1v out of whack, so they may as well not have a warranty because i dont know how you could have a voltage gradient that large unless the battery was like, dead shorting internally and about to catch fire


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## remy_martian (Feb 4, 2019)

They might not be balanced. 

Did you try charging the lower voltage cells to get them within a few millivolts of the others?


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## joekitch (Sep 13, 2013)

not yet
but considering the other modules are very well balanced, i assumed they were balanced charged before being shipped out at first?
however i can try doing a balance charge and wait another month to see if they fall out of line again


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## remy_martian (Feb 4, 2019)

You're stuck with them, so why not?


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