# Size of the modules in a Chevy Bolt pack?



## jasonwray (Sep 30, 2019)

The 10s modules are approximately 19x14x4.5"


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## brian_ (Feb 7, 2017)

Those dimensions are presumably for the bare modules. They are clamped down to thermal management plates ("chill plates", although they are also used for heating, carrying circulating coolant), adding height. The 8S modules are proportionately shorter. Both module sizes are placed end-to-end (so about 38" long using jasonwray's measurement) in the pack. The pack has four pairs of 10S modules, with a pair of 8S modules sitting above the rear-most of the 10S pairs (so the pack bumps up under the Bolt's rear seat).


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## rwaudio (May 22, 2008)

I've measured a single module as:
13.6" not including terminals, 14.5" with terminals x 19.375" x 4.3" not including mounting ears, 4.55" including mounting ears. This ignores the plastic lifting eye molded into the plastic where the modules were joined (it sticks up another 0.5").

So in short if you cut off the lifting eye, and grind off the mounting ears the module is 4.3" and they could be stacked easily.

If you intend to tap into the BMS connectors the mating connector is:
https://www.digikey.ca/en/products/detail/molex/0347910080/3202548
and pins:
https://www.digikey.ca/en/products/.../3178487?s=N4IgTCBcDaIKwDYAMSwGYkBYwEYQF0BfIA

Both connectors are populated from the left looking at the back, 6 pins on the terminal side, and 5 pins on the non-terminal side of the battery.


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## brian_ (Feb 7, 2017)

rwaudio said:


> I've measured a single module as:
> 13.6" not including terminals, 14.5" with terminals x 19.375" x 4.3" not including mounting ears, 4.55" including mounting ears. This ignores the plastic lifting eye molded into the plastic where the modules were joined (it sticks up another 0.5").


Excellent details 



rwaudio said:


> So in short if you cut off the lifting eye, and grind off the mounting ears the module is 4.3" and they could be stacked easily.


These modules are intended to be cooled (and warmed) by contact with a "chill plate" on one of the large faces. It seems like a bad idea to directly stack them, and if stacking them with a chill plate the plate would of course add to the height.

It would be possible to sandwich a chill plate between two modules, so the same two-sided plate provides thermal management to both modules. This is apparently the configuration used by Rivian in their proposed pickup truck.


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## rwaudio (May 22, 2008)

brian_ said:


> Excellent details
> 
> 
> These modules are intended to be cooled (and warmed) by contact with a "chill plate" on one of the large faces. It seems like a bad idea to directly stack them, and if stacking them with a chill plate the plate would of course add to the height.
> ...


Yes and yes, simple yet to be tested idea attached. The plate between the module would be roughly 0.1-0.125" plus two 0.02" thermal pads. 
This definitely isn't tesla level cooling, however the difference is time, will a system like this get heat out (or in) quick enough.


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## brian_ (Feb 7, 2017)

rwaudio said:


> Yes and yes, simple yet to be tested idea attached. The plate between the module would be roughly 0.1-0.125" plus two 0.02" thermal pads.
> This definitely isn't tesla level cooling, however the difference is time, will a system like this get heat out (or in) quick enough.


For clarification, it appears that you are planning to unstack the cells and frames of the Bolt module, remove and replace each existing thermal transfer plate with a new plate (or just add the new plate, making that stack longer), stack blocks (presumably of aluminum) between tabs of the new plates, and cool the stack of blocks with a single loop of tubing carrying coolant. That makes some sense, but seems like a lot of work and a lot less effective than just clamping the module to a chill plate which would be no thicker than the new tabs and blocks.


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## Deane (Mar 21, 2020)

Do you mean the Chevy Volt?


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## rwaudio (May 22, 2008)

brian_ said:


> For clarification, it appears that you are planning to unstack the cells and frames of the Bolt module, remove and replace each existing thermal transfer plate with a new plate (or just add the new plate, making that stack longer), stack blocks (presumably of aluminum) between tabs of the new plates, and cool the stack of blocks with a single loop of tubing carrying coolant. That makes some sense, but seems like a lot of work and a lot less effective than just clamping the module to a chill plate which would be no thicker than the new tabs and blocks.


These are the bolt modules as they come, no major modifications. (other than removing the lifting eye, and possibly grinding off the mounting feet if required. I modeled it as a rectangle for simplicity without the pressed steel mounting plate on the one end. 

There is no added plate between the cells, it's just a flat aluminium plate to bring the heat out/in to the cooling/heating tube located between the terminals. This keeps the outer dimensions as compact as possible while allowing liquid heating and cooling. 

If there was a cost effective chill plate of the correct size, it must cover the total width, and a fair amount of the height, I'd happily use that, but it looks like it's going to be a custom item. It has to be between 17.25" and 19" wide by 7-8" minimum to 10.75" ideal. For my application I'd like the coolant inlet/outlet to be on the longer dimension closer to the centre so it doesn't come near the battery terminals.

For clarity, the image depicts 6 complete 10S LG/Chevy Bolt modules with cooling between them (60S or about 36kwh). The individual parts are shown unassembled on the left.


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## rwaudio (May 22, 2008)

Deane said:


> Do you mean the Chevy Volt?


Chevy Bolt with a B.


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## remy_martian (Feb 4, 2019)

Seems like a whole lot of trouble for zero net gain.

Why don't you leave the thick aluminum cans around the cells and simply clamp them to your chiller blocks?


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## jasonwray (Sep 30, 2019)

Possible cooling option: https://www.instagram.com/p/CBRABHlnP_v/?igshid=ltdduen0ebm6


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## rwaudio (May 22, 2008)

jasonwray said:


> Possible cooling option: https://www.instagram.com/p/CBRABHlnP_v/?igshid=ltdduen0ebm6


That will cool/heat a few of the cells really well, the centre, and outside cells don't touch the chill plate. 

This was my point made previously, you need a very specific size to properly cover all of the cells. A thermal pad won't distribute the heating/cooling, you would need a heat spreader.

Give me a total for a proper heat spreader, two of those chill plates and all the required thermal pads...

I'm using 10 modules in my car.

I predict very expensive...


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## rwaudio (May 22, 2008)

remy_martian said:


> Seems like a whole lot of trouble for zero net gain.
> 
> Why don't you leave the thick aluminum cans around the cells and simply clamp them to your chiller blocks?


Looks like I'll have to do a new rendering to make things clear. The WHOLE module is represented IE there are 6 complete 10S modules linked together. Plus the parts laid out individually on the left.

This isn't some overcomplicated modification to a single module.


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## remy_martian (Feb 4, 2019)

oh...I thought it was a cell block (I'm sure Brian has a standard term) of 2 cells in their plastic carrier the way you drew it


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## remy_martian (Feb 4, 2019)

jasonwray said:


> Possible cooling option: https://www.instagram.com/p/CBRABHlnP_v/?igshid=ltdduen0ebm6


How do they flatten the tubes?


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## brian_ (Feb 7, 2017)

rwaudio said:


> For clarity, the image depicts 6 complete 10S LG/Chevy Bolt modules with cooling between them (60S or about 36kwh). The individual parts are shown unassembled on the left.


Ah... I incorrectly assumed that you were showing the cells within one module, rather than an enormous 14.5" x 19.375" x 27" block of six modules.

In that case, the design is similar to that used by snowdog in his _Electric Supercar_ for the modules mounted in the front of the car. He also has normal chill plates which were custom made for the the modules which are mounted behind the driver. Perhaps snowdog can point you to which point in which YouTube video those cooling systems is shown.

Thermal conduction by the thin plate to a small block on one edge seems unlikely to me to provide significant cooling, or to help even out temperatures across modules very well. It might just cause one end of the middle cells of each module to run cooler than the others, increasing imbalance.


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## brian_ (Feb 7, 2017)

remy_martian said:


> oh...I thought it was a cell block (I'm sure Brian has a standard term) of 2 cells in their plastic carrier the way you drew it


So did I.

For those not following what remy and I are saying, these modules are stacks of cells in plastic frames (or carrier), with one frame per two cells, and a heat conduction plate between each pair of frames (so each cell is against a plate on one side). They don't form a usable module until there are special end frames added and the stack is bolted together, the cell tabs ultrasonically welded together, and terminals are added.


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## brian_ (Feb 7, 2017)

jasonwray said:


> Possible cooling option: https://www.instagram.com/p/CBRABHlnP_v/?igshid=ltdduen0ebm6


That's a nice part. It is Aavid 416201U00000G sold by Mouser in Canada. That size is a couple hundred Canadian dollars, and is smaller in both dimensions that a Bolt module; it is presumably cheaper in the U.S., although the first U.S. source I found (Allied) charges about the same (US$142). There are other distributors: at DigiKey the same item is CA$147.38, so shopping around would pay.



remy_martian said:


> How do they flatten the tubes?


The description says it has


> a continuous tube that is press fitted into an extruded aluminum plate


From the datasheet, it appears that the round tubes are bent to the serpentine shape, placed in the plate grooves (with the top side of the tube protruding because the groove is wider but shallower than the tube diameter) then pressed down with a flat plate to deform into a "D" shape. This embeds the tube without having to build a complete "sandwich" with two plates, presses the tube and plate into tight contact, and exposes the tube directly to the component to be chilled (which is normally another metal structure in the case of the electronics that they are building for).

The manufacturer is the Aavid Thermal Division of Boyd. Their Hi-Contact™ Tube Liquid Cold Plate product page lists various sizes, and the go quite large, but of course none match the length and width of the Bolt modules. Figure 4 of the datasheet (as posted by Mouser) shows that custom sizes are available, and what the parameters are; they can go quite a bit larger than a Bolt module, but custom construction is probably not reasonable for a small quantity. I suppose anyone with a mill could make suitable plates and anyone with a large enough press could fit the tubes into a plate; it might even be possible to use a roller press.


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## brian_ (Feb 7, 2017)

rwaudio said:


> That will cool/heat a few of the cells really well, the centre, and outside cells don't touch the chill plate.
> 
> This was my point made previously, you need a very specific size to properly cover all of the cells.


Even if a chill plate like this is only half the width of the modules, and about the same length, it could cool (or heat) far more evenly than the proposed design with a plate sized to match the module face and a cooling block on just one small part of one edge.

The stock plates which are between each pair of cells have the same issue, because they are cooled on only one edge; however, they are cooled along the entire edge, and they fold over the long side of the cell to provide substantial area for contact with the chill plate.


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## brian_ (Feb 7, 2017)

remy_martian said:


> Why don't you leave the thick aluminum cans around the cells and simply clamp them to your chiller blocks?


What cans? Pouch cells (such as these from LG) don't normally come in cans. Even the early Leaf design has a can around a four-cell module, not individual cells. The cells do look metallic, due to the foil layer in the pouch. Also, in the LG modules (such as these from the Bolt and the ones in the Pacifica) the heat transfer plates between cell pairs bend 90 degrees at the long cell edges, resulting in a package that looks like one corner of a complete rectangular can, but is just two sides.

The heat transfer plates are described as 'sheetmetal “C” sections' in tiger82's excellent thread _Modified Bolt Pack for Tesla Cobra EV Race Car_. 

But yes, those thin heat transfer plates exist to be clamped against a rigid chiller plate.


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## brian_ (Feb 7, 2017)

Deane said:


> Do you mean the Chevy Volt?


Batteries from the plug-in hybrid Chevrolet Volt have been popular in conversions, because they are available, and can handle a high discharge rate. Part of that performance is the result of its highly capable cooling system, which uses fluid-filled cooling plates between individual cells.

This is about the Chevrolet Bolt battery which is similarly constructed, except that instead of fluid-filled cooling plates between individual cells it depends on a fluid-filled plate against one side of the module. The cells are also much larger (longer and wider), which changes the module size. Since the Bolt is a pure battery-electric EV it has a much larger battery than the Volt... about four times the capacity. The Bolt has been in production long enough that used modules and complete batteries are available.

The Chrysler Pacifica Hybrid van uses very similar modules (to those in the Bolt), which are widely available from EV conversion suppliers; the are usually just called "LG Chem modules", as if that were the only module that LG makes (but the Volt, Bolt, and other vehicles use LG Chem modules).


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## remy_martian (Feb 4, 2019)

Sheet metal cans, c-sections...same difference

Looks like it was designed by ex-pat Japanese tab/slot tin toy designers from 60 years ago 😎


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## brian_ (Feb 7, 2017)

remy_martian said:


> Sheet metal cans, c-sections...same difference


A "can" would normally suggest a complete container, but okay, we're now on the same page.

So yes, those plates are suitable and should be used unless replaced by a different cooling plate between each cell pair. rwaudio does intend to keem them, to depend on them to conduct heat between the cells and the cooling system, and to clamp the module to a cooling plate... just not the style of cooling plate used in a Bolt or any other production EV or hybrid.


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## remy_martian (Feb 4, 2019)

tiger82 did a killer build & writeup, inspiring in fact in my case, but sadly he's off living life instead of hanging out on this forum answering our questions, lol

Meanwhile, wtf was LG thinking by putting that bump in the hold-down slot in the can (it's cheap, but horrible) ? Keeps the modules from siamese-ing nicely and the geometry is such a PITA that my master craftsmanship using my 8lb persuader only pushes that lump around vs making it disappear. That leaves Mr Cutoff wheel. And then deburring, and then...

All fine and good for one, but a few hundred?

There's a reason AAVID is not found in OEM EV's - they're at the opposite end of the spectrum from LG on cost, apparently.

The thrashing on ideas continues...


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## brian_ (Feb 7, 2017)

remy_martian said:


> There's a reason AAVID is not found in OEM EV's - they're at the opposite end of the spectrum from LG on cost, apparently.


I think Aavid is just targeting a different market. One of their units under an inverter would make sense; I think even they would be surprised to see anyone was putting ten of them under battery modules. Their high quantity pricing is for a manufacturer putting one in each of many units, not one person putting a whole bunch of them in a single vehicle.


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## remy_martian (Feb 4, 2019)

With online machine shops, even the inverter application is dicey...they're stuck in 1990's pricing. But, they still offer the product, so someone's finding a value proposition there.


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## JaredG (Dec 28, 2020)

rwaudio said:


> I've measured a single module as:
> 13.6" not including terminals, 14.5" with terminals x 19.375" x 4.3" not including mounting ears, 4.55" including mounting ears. This ignores the plastic lifting eye molded into the plastic where the modules were joined (it sticks up another 0.5").
> 
> So in short if you cut off the lifting eye, and grind off the mounting ears the module is 4.3" and they could be stacked easily.
> ...


 Super helpful,do you know where I could find a diagram for these pins? On a 10s I have 16 leads


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## Tremelune (Dec 8, 2009)

So like, does anyone have any photos of the individual modules, cell packs, and/or cells...? I'm having trouble understanding how these things connect to one another, and therefore how they can be reused and reconfigured...The less dismantling the better, but 3-foot runs of batteries aren't all that helpful for converting ICE cars...

John Kelly breaks this down, but stops at the large "section" level:



https://cleantechnica.com/2018/07/08/tesla-model-3-chevy-bolt-battery-packs-examined/


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## brian_ (Feb 7, 2017)

Tremelune said:


> So like, does anyone have any photos of the individual modules, cell packs, and/or cells...? I'm having trouble understanding how these things connect to one another, and therefore how they can be reused and reconfigured...The less dismantling the better, but 3-foot runs of batteries aren't all that helpful for converting ICE cars...
> 
> John Kelly breaks this down, but stops at the large "section" level:


There are not enough hours in the day to watch John Kelly's videos, but I assume by "section" he means two modules, placed end-to-end for a total of about three feet, spanning the width of the pack. The bottom layer is four of those module pairs (each module 10S3P), and the top layer is one module pair (each module 8S3P). The end-to-end pair are electrically separate (thus two modules), but mechanically joined in some way... similar to the way nine modules are assembled into three blocks or sections in the first-generation Volt, or seven modules are assembled into three blocks or sections in the second-generation Volt.

My understanding is that the blocks or sections are easily broken apart into individual modules; breaking down the modules into small chunks or individual cells would mean breaking welded cell tab connections.

This thread gets into the Bolt battery internals, breaking it down to individual cells in the first post:
Modified Bolt Pack for Tesla Cobra EV Race Car


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## remy_martian (Feb 4, 2019)

Just like the damned Volt, the Bolt cells are doomed to extinction after a few years' run. 

Tesla is changing their modules to Howitzer-shell cells, who knows what VW are doing?

SAE, asleep at the wheel again, this time in standardizing modules.

jI guess it doesn't matter if you're doing a one-off build, but I was hoping to do _one_ battery box design that I could use in a few projects. 

Life's too short to be doing stuff over again.

/rant off


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## brian_ (Feb 7, 2017)

remy_martian said:


> Just like the damned Volt, the Bolt cells are doomed to extinction after a few years' run.
> 
> Tesla is changing their modules to Howitzer-shell cells, who knows what VW are doing?
> 
> ...


The Bolt has been in production for several years, and the new-for-2022 second generation appears to use the same format (given that the new battery fits the old car), just with 10% higher-capacity cells of the same size. Although GM is introducing a new series of battery modules in their Ultium components (which will be shared across all of the coming EV models of the next few years), they're not using them in the Bolt. The result in a few years will be a decade of a high-volume production car with a consistent battery module format... not bad.

I support the idea of standardization where appropriate, and it's good that there are some standards by VDA, but I can understand why they're not widely used. Most automotive components are not standardized, and battery modules are so important to the design of the vehicle that I understand not constraining the design to use a specific format. Eventually modules and any standardization of replaceable components may disappear in production EVs, if batteries composed of directly mounted cells (with no division into modules) - called "cell to pack" or CTP in current industry jargon - catch on.

For now, if you want a battery module format which is available from more than one manufacturer and in more than one internal configuration, the VDA 355 format (named for the 355 mm length, but the other dimensions are also standardized) appears to be the best bet. Currently, modules in this size appear to include:

CALB 6S2P (from Zero EV)
CALB 4S3P (from Zero EV)
LG 3S4P (from Zero EV)
OX-Drive Energy 6S (from ElectricGT)
OX-Drive Energy 4S (from ElectricGT)
VW e-Golf modules with 4S3P SDI cells
various Chinese suppliers of NCM modules (e.g. 6S Westart, 4S Westart)
A123 Systems PHEV2 modules in 12S1P, 6S2P, 4S3P
I'm sure Electric GT doesn't build their VDA 355 modules, so they may actually be CALB or LG or SDI or Westart or A123 or anyone else.

VW's MEB platform appears to use the larger VDA 590 standard, but other sources of this size are not as common as VDA 355.

By the way, if anyone has a good source information about the VDA standards, I'm interested.


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## brian_ (Feb 7, 2017)

Tremelune said:


> So like, does anyone have any photos of the individual modules, cell packs, and/or cells...? I'm having trouble understanding how these things connect to one another, and therefore how they can be reused and reconfigured...The less dismantling the better, but 3-foot runs of batteries aren't all that helpful for converting ICE cars...


With dimensions (from the beginning of this thread) this time...

rectangular flat pouch cells are held in plastic frames like picture frames, overall dimensions 13.6" wide x 4.3 tall x ~0.7" thick
stacks of 30 cells wired in 10S3P are assembled to form 13.6" x 19.375" x 4.3" (plus mounting tabs and terminals) modules, and stacks of 24 cells wired in 8S3P are assembled to form 13.6" x ~16" x 4.3" (plus mounting tabs and terminals) modules
pairs of identical modules are joined end-to-end to form long blocks (~40" or ~32")
the two-module blocks are place with the long dimension lateral, shortest dimension vertical, all four pairs of 10S modules in one bottom layer, the pair of 8S modules as a second layer at the back end
all modules are connected in series
BMS wiring, disconnects, fuses, etc are added and the whole thing is wrapped in metal clamshell
So the metre-long pairs of modules are long, but they should be easily mechanically disassembled into individual modules (half that length) without electrical changes at all. There is presumably a multi-pin connector for the BMS on each module, like a Volt battery.


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## MetalOperaGuy (Oct 30, 2019)

brian_ said:


> With dimensions (from the beginning of this thread) this time...
> 
> rectangular flat pouch cells are held in plastic frames like picture frames, overall dimensions 13.6" wide x 4.3 tall x ~0.7" thick
> stacks of 30 cells wired in 10S3P are assembled to form 13.6" x 19.375" x 4.3" (plus mounting tabs and terminals) modules, and stacks of 24 cells wired in 8S3P are assembled to form 13.6" x ~16" x 4.3" (plus mounting tabs and terminals) modules
> ...


Brian (and all), I am having a terrible time looking for the physical dimensions for the stock Bolt pack - I'm wondering if a salvaged or new battery pack will fit in my build without modification. Would anyone have those dimensions to share?

Greatly appreciated!


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## brian_ (Feb 7, 2017)

MetalOperaGuy said:


> Brian (and all), I am having a terrible time looking for the physical dimensions for the stock Bolt pack - I'm wondering if a salvaged or new battery pack will fit in my build without modification. Would anyone have those dimensions to share?


You might try looking through Yabert's project - Westfalia T3 with Chevy Bolt drivetrain - for information, since he used a complete Bolt battery pack. If the dimensions are not in his thread, you could contact him as ask if he has dimensions.


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## Swing (Apr 25, 2021)

Having a Chevrolet Bolt (European version) I can say that battery degradation is really low. 4 years 100.000km I am around 1.6% degradation only. I must say that there is no accurate way of calculating this, so lets say it is around 2%, anyway, really low.

I think they make nice batteries for a single project, but perhaps nothing for something you want to build several times in future, just like Volt batteries.
Although they must be very similar to Hyundai Kona and Kia Nero.

Since there is a recall on these vehicles, there might come oppertunities to find batteries that were replaced and just don't use the top 10%


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## kitlacey (Nov 26, 2021)

rwaudio said:


> I've measured a single module as:
> 13.6" not including terminals, 14.5" with terminals x 19.375" x 4.3" not including mounting ears, 4.55" including mounting ears. This ignores the plastic lifting eye molded into the plastic where the modules were joined (it sticks up another 0.5").
> 
> So in short if you cut off the lifting eye, and grind off the mounting ears the module is 4.3" and they could be stacked easily.
> ...


Great link for the BMS pins. Do you know where I can find a list of which pin is which so I can hook the modules up to a Battery Management System?


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