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Discussion Starter · #1 ·
Hello everyone,

My wife and I are happy to join this amazing forum and want learn and share with like-minded people like you. We are so excited for our build and have been lucky to find the right Jeep!

Veronika grew up watching Gilmore Girls in Austria and always dreamed of owning the Jeep they drove in the show. It was a 1999/2000 Jeep Wrangler. We found one on CL in Idaho and flew there to pick it up back when it was still warm out...

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And the last time it had one of these stuck in it:

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It is a good start as it has a few powertrain issues so we didn't feel so bad about pulling it out. That will be our Christmas vacation since Austria is locked down with COVID fear.

We are still debating the powertrain options. Probably down to a Model 3 RDU from Zero-EV with their gear reduction and LSD mounted transversely in the car to keep 4WD (but then it is full-time 4WD) or use a Cascadia Motion iM-225 + Torquebox into the stock NP231 so we can have 2H - 4H - 4 still... It will probably be all controlled using the AEM EV control system. I think the Tesla swap has the added "cool" factor, but the mechanical mounting aspect might be more complicated (plus the loss of the 2H option which should be more efficient). Still debating.

For batteries, we have a few Mach-E packs and those modules are either 4P8S or 4P7S:

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Using the modules as-is will be tough to get the voltage up to where we need it (~400V) so we are exploring re-configuring the modules into 2P "slices". This is two cells in parallel with the cooling plate in-between. Multiple of these just stack together to make the modules.

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This is halfway easy as the bus bar configuration and the modular construction of the modules make the slices have 2 cells each that are in parallel and you should be able to cut the bus bars here:

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...and have then a 2P2S "slice". The challenge is reconnecting the bus bars on the other side of the module...

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If anybody has some suggestions, we are all ears... We are exploring mechanical connections as well as spot welding new bus bars to the existing bus bars (to not cut the factory welds on the cell tabs).

We are taking the cells to Orion BMS so they can characterize the cells to hopefully make them available for other DIYers in the future. They are nice 65Ah LG cells.

Anyway, we are excited to start being a part of this community and to pull the current powertrain out and see how much space we really have. Veronika will be documenting the entire process (the good and the bad) on her channel here:

https://www.youtube.com/c/ElectrifiedVeronika

Cheers!
Don and Veronika
 

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The obvious alternative to reconfiguring the cells of a Mach-E extended range pack (4P and so 260 Ah) is to use a Mach-E standard range pack instead, which has eight 10S3P modules and two 8S3P modules (so 195 Ah)... but of course if you want to go all the way down to 130 Ah modification would still be needed and as you explained it's easier to modify the 4P components to 2P than to start with 3P.
(All of this assumes that the cells are 65 Ah)
 

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We are still debating the powertrain options. Probably down to a Model 3 RDU from Zero-EV with their gear reduction and LSD mounted transversely in the car to keep 4WD (but then it is full-time 4WD) or use a Cascadia Motion iM-225 + Torquebox
Many of us are familiar with the Cascadian Motion motor line, all models of which are based on BorgWarner (formerly Remy) HVH cores in various housing, but I didn't recognize the "iM-225" model name. This turns out to be an HVH250-115D motor core and CM200 inverter in an integrated housing. It's very tall because of the inverter on top; if it would go in the transmission tunnel it would be too tall, so would the plan be to cut out the top of the tunnel and expand into the under-dash space? A SS-250-115-D motor would presumably fit in the unmodified tunnel with the inverter mounted separately.
 

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Discussion Starter · #4 ·
The obvious alternative to reconfiguring the cells of a Mach-E extended range pack (4P and so 260 Ah) is to use a Mach-E standard range pack instead, which has eight 10S3P modules and two 8S3P modules (so 195 Ah)... but of course if you want to go all the way down to 130 Ah modification would still be needed and as you explained it's easier to modify the 4P components to 2P than to start with 3P.
(All of this assumes that the cells are 65 Ah)
Thanks Brian. Good idea... I wasn't aware of the 3P configurations and none of the Mach-E packs I have seen had his configuration.
 

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... I wasn't aware of the 3P configurations and none of the Mach-E packs I have seen had his configuration.
I guess either the extended range is more popular, or the drivers of those crash more. ;)

The standard range pack has only a single layer of modules, so it basically missing those top two (and so the case top is nearly flat), but the modules are not the same lengths. Like the extended range, the modules within a pack are all the same except a shorter pair in the front so that the case can taper in width. All modules of both packs all use the same cells, and their configurations are:
  • ext range long modules: 8S4P, so 32 cells
  • ext range short modules: 7S4P, so 28 cells
  • std range long modules: 10S3P, so 30 cells
  • std range short modules: 8S3P, so 24 cells
The overall configuration of the standard range battery is then 96S3P, versus the 94S4P of the extended range, so they have slightly different overall operating voltages.

If you use the standard range pack's modules without modification, and keep all of them to hit your desired voltage, you still end up with a lot of battery to fit into a TJ Wrangler!

The standard range pack will also be used in the E-Transit (EV version of Transit van and chassis-cab truck).

Munro did a teardown of the standard range pack. Some of the people there (especially Sandy Munro) are pretty clueless about batteries (in their first video about this battery they even though it was a different brand of module), but they show the internals well:
 

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Discussion Starter · #7 ·
Munro did a teardown of the standard range pack. Some of the people there (especially Sandy Munro) are pretty clueless about batteries (in their first video about this battery they even though it was a different brand of module), but they show the internals well:
Thanks for the info. Yeah, we know Sandy. Veronika visited him a few months ago. And yes, his videos are fun to watch sometimes when it comes to batteries. I have been in the EV battery testing industry for 15 years and Veronika has a PHD in Technical Physics and has a strong background on battery simulations and lifetime prediction models so we get the popcorn out when Sandy starts reading...I mean...talking about batteries.
 

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Discussion Starter · #8 ·
Although when I watch that Munro video again, I see the exact same bus bar configurations that we found in the 4P8S and 4P7S modules we have...so I am not sure how they are able to use it in a 3P10S configuration...maybe this is the 3P8S module...and they just put blanks in for the missing cells? You can easily tell the anode and cathode side by the spot weld colors.

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Although the label on his module in the video does say 6.3kWh where ours say 7.4 and 8.5 (if my vision is good enough)...

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Although when I watch that Munro video again, I see the exact same bus bar configurations that we found in the 4P8S and 4P7S modules we have...so I am not sure how they are able to use it in a 3P10S configuration...maybe this is the 3P8S module...and they just put blanks in for the missing cells? You can easily tell the anode and cathode side by the spot weld colors.

View attachment 125426
I noticed that, too. My guess is that half of the locations where tabs are welded to the plates have two cell tabs overlapped (so three tabs for three cells on the two legs of the connector), while in the 4P modules every location has two cells tabs overlapped (so four tabs for four cells on the two legs of the connector).

I'm sure that there are no blank cell locations, as that would require a spacer to maintain compression in the stack, would waste a ridiculous amount of volume, and would make the two packs the same physical size.
 

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Hello everyone,

My wife and I are happy to join this amazing forum and want learn and share with like-minded people like you. We are so excited for our build and have been lucky to find the right Jeep!

Veronika grew up watching Gilmore Girls in Austria and always dreamed of owning the Jeep they drove in the show. It was a 1999/2000 Jeep Wrangler. We found one on CL in Idaho and flew there to pick it up back when it was still warm out...

View attachment 125412 View attachment 125413

And the last time it had one of these stuck in it:

View attachment 125414

It is a good start as it has a few powertrain issues so we didn't feel so bad about pulling it out. That will be our Christmas vacation since Austria is locked down with COVID fear.

We are still debating the powertrain options. Probably down to a Model 3 RDU from Zero-EV with their gear reduction and LSD mounted transversely in the car to keep 4WD (but then it is full-time 4WD) or use a Cascadia Motion iM-225 + Torquebox into the stock NP231 so we can have 2H - 4H - 4 still... It will probably be all controlled using the AEM EV control system. I think the Tesla swap has the added "cool" factor, but the mechanical mounting aspect might be more complicated (plus the loss of the 2H option which should be more efficient). Still debating.

For batteries, we have a few Mach-E packs and those modules are either 4P8S or 4P7S:

View attachment 125415

Using the modules as-is will be tough to get the voltage up to where we need it (~400V) so we are exploring re-configuring the modules into 2P "slices". This is two cells in parallel with the cooling plate in-between. Multiple of these just stack together to make the modules.

View attachment 125417

This is halfway easy as the bus bar configuration and the modular construction of the modules make the slices have 2 cells each that are in parallel and you should be able to cut the bus bars here:

View attachment 125416

...and have then a 2P2S "slice". The challenge is reconnecting the bus bars on the other side of the module...

View attachment 125418

If anybody has some suggestions, we are all ears... We are exploring mechanical connections as well as spot welding new bus bars to the existing bus bars (to not cut the factory welds on the cell tabs).
I assume you've seen this 2P reconfig?

 

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Discussion Starter · #12 ·
I assume you've seen this 2P reconfig?

Thanks for the LINK!!! This is exactly what we were thinking to do so this confirms our plans. This is perfect. I did not see this but so great. We can easily do this with the Mach-E modules. Just will take time to cut the bus bars...they are very hard and you have to do it in steps to not heat the cell tabs which heats the cells too much. I will even add connection points for the BMS to the new bus bars.

Thanks so much again for the link!!
 

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Discussion Starter · #14 ·
BTW...it's kind of funny... I would have called these Mach-E modules 8s4p and 7s4p, but the actual molded cover on the modules had the nomenclature reversed and I was actually thinking I've been saying it backward all these years...

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BTW...it's kind of funny... I would have called these Mach-E modules 8s4p and 7s4p, but the actual molded cover on the modules had the nomenclature reversed and I was actually thinking I've been saying it backward all these years...

View attachment 125511

View attachment 125512
It has been done both ways; there is no authoritative definition of the notation, so neither is correct. I put the lowest level at the end, reflecting the normal practice for numeric values. We have debated this in this forum, probably a couple of years ago or more.

As long as the relevant number precedes the letter ("P" or "S"), it works.
 

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4 parallel of 8 series is very different than 8 series of 4 parallel.

The cell counts are the same. The pack voltage is the same. The max discharge is the same. But....

The first has two BMS connections, the latter has 9. The balancing capability is night & day.
 

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4 parallel of 8 series is very different than 8 series of 4 parallel.

The cell counts are the same. The pack voltage is the same. The max discharge is the same. But....

The first has two BMS connections, the latter has 9. The balancing capability is night & day.
Yes, but this module has the groups of 4 cells each connected in parallel, then 7 or 8 of those groups connected in series; it has 8 (for 7S) or 9 (for 8S) BMS taps. I would write that as 7S4P or 8S4P, but the moulded-in marking is "4P7S" and "4P8S". There's no question about the physical configuration of the module, which follows the industry-standard practice for EV battery configuration; the discussion was only about the unusual notation used in the embossed markings... perhaps designed by one of those marketing people. ;)

By the way, four parallel strings each of 8 cells in series would have 45 BMS taps (in 4 groups of 9 per string), not just 2 - I assume that was just a typo.
 

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Discussion Starter · #19 ·
Yeah, like I said, I would have always said 8s4p but then when I saw the molded plastic piece...I though more about it. Then I was thinking that actually 4p8s makes a lot of sense and it better describes the module and pack from a BMS perspective. First you have 4 cells in parallel that you then connect in series... Then the full pack is really 4pXs...

As mentioned, 4 parallel and 8 in series is very different from 8 in series, and then 4 in parallel...from a BMS and balancing perspective.
 

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Arrrgh
It's just a notation issue; there's no question how these modules are configured or whether it is the most appropriate configuration. Most of us normally use a notation with the lowest level of detail at the end, the way numbers work most to least significant digits). What these modules have moulded into the cover has the lowest level of detail at the beginning; that may be LG Chem's standard notation, but it's hard to tell because it's hard to find genuine LG Chem documentation at the module level.
 
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