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Discussion Starter #1
Hey guys,

I’m still trying to decide on batteries for an ev samurai. Which would be better Nissan Leaf modules?? Or Chevy volt modules??

Thanks
 

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That's way too vague a question. If you know your operating voltage, power requirement, energy storage requirement, willingness to put in a liquid cooling system, space constraints, and weight budget... then maybe people can offer suggestions about which of these alternatives might work better, and why.
 

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Yes, More info is needed, but if you go on ebay and look at both Leaf and Volt battery modules, the Leaf batteries are a bit cheaper per module. The Volt battery packs are not as modular as the leaf modules, but the Volt module is grouped in higher voltage rating as they group the series cells together, As in 12S and 16S. So I can see some benefit of the Volt Batteries. But I like the lower price of the Leaf modules and they allow you to group serial and parallel groupings into a more customizable fashion.
 

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Discussion Starter #4
Ok the pack voltage is around mid 50Vs. This machine is for the woods. The vehicle is a Suzuki Samurai.
Controller: Paul and Sabrina
Motor: GE 9 inch series...
 

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Ok the pack voltage is around mid 50Vs.
That's a start :)

But why do you want such a low voltage? Assuming for now that you do...

The Volt battery packs are not as modular as the leaf modules, but the Volt module is grouped in higher voltage rating as they group the series cells together, As in 12S and 16S. So I can see some benefit of the Volt Batteries. But I like the lower price of the Leaf modules and they allow you to group serial and parallel groupings into a more customizable fashion.
The higher series cell count of the Volt modules means fewer modules (which is convenient in a way), but makes it hard to fit a low-voltage system.

To get about one-sixth of a common 360 volt (nominal), you would be using 16 cells (instead of the usual 96) in series - a 16S configuration.

Some useful description of the Volt batteries: 2016 CHEVROLET VOLT BATTERY SYSTEM
  1. The first-generation Volt pack has 6S and 12S modules (with all cells in 3-cell parallel groups), and those 9 modules are bolted together into four blocks... none of which are 16S.
  2. The second-generation Volt pack has 12S and 16S modules (with all cells in 2-cell parallel groups), and those 7 modules are bolted together into four blocks... none of which are just 16S. Five of the modules are 16S by themselves, so you could use just those modules, but then you would be connecting the modules in parallel so you would need five sets of BMS inputs.
Reconfiguration work would be required for either generation, and without breaking cell tab welds to change modules sizes, it would not be possible to rearrange either entire pack into a 16S 18P (first-gen) or 16S 12P (second-gen) pack.

It seems to me to be a lot easier to use the classic (24 kWh, 30 kWh, or 40 kWh... not the new 62 kWh) Leaf battery for a low-voltage application like this. All of the modules are identical and only 2S2P (although modules are glued in pairs), with every cell connection exposed via a substantial BMS tap terminal which can be used to parallel them together. You could connect sets of 6 modules (3 pairs) in parallel (connecting all of the terminals together, not just the ends) into 2S12P blocks, then run all 8 blocks in series to make a 16S12P battery with the entire capacity (24 kWh, 30 kWh, or 40 kWh) of the Leaf. If there isn't that much room for battery in the Samurai, you could use less than 8 sets for the same voltage and corresponding lower capacity.
 

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Discussion Starter #6
Yes I do want to stay low voltage... low to mid 50's... 48V system voltage if you would...

That being said, I have been looking at the Nissan leaf pack with 49 modules.... It is supposed to be a 7P7S Nissan leaf module pack. But I am not dead sold on leaf modules. here are questions I have:

1. can you infact put Leaf modules in parallel with each other and not have a problem? Or do you need a total of 7 BMS managing each individual 7s configuration?
2. I hear alot about how the leafs did not have liquid cooling like the volts did and the cells could have been more degraded during use as apposed to the Volt modules who use Liquid cooling.
3. When I look at these Leaf Modules, they are either G1 or G2 cells. which is better?
4.Also I see that some of these Modules are 60% and the Gen 2 Modules are 70%. But how long will these modules last at this state? How many more years do I have left? Is it really worth spending 2000.00 plus and they only last for 4 to 5 years? I am not sure its worth it..Am I looking at this the right way??

thanks for all your input on this
 

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Yes I do want to stay low voltage... low to mid 50's... 48V system voltage if you would...
But why?

That being said, I have been looking at the Nissan leaf pack with 49 modules.... It is supposed to be a 7P7S Nissan leaf module pack.
As I said in the other thread where this was discussed, a Leaf pack contains 48 modules, so if someone has already assembled this they used modules from at least two packs, and if you plan to build this you will not be able to with the modules from a single pack.

1. can you infact put Leaf modules in parallel with each other and not have a problem? Or do you need a total of 7 BMS managing each individual 7s configuration?
Yes, you can just parallel them and use a single BMS. Did you not believe this when we first discussed it (in Nissan Leaf Modules), or when I listed this above, or do you just not understand this yet? The Leaf module is the only common EV module which gives you high-current access to every cell level (instead of just a thin wire for BMS use), so you can effectively connect them in parallel at the cell level.

2. I hear alot about how the leafs did not have liquid cooling like the volts did and the cells could have been more degraded during use as apposed to the Volt modules who use Liquid cooling.
The Leaf certainly has cell degradation issues related to heat management, especially in some versions (there have been at least four different versions of cells used in these packs). On the other hand, the Volt runs just as much power as the Leaf from a much smaller battery, so the cells are pushed much harder and so they need liquid cooling just to survive.
 

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Discussion Starter #8
Well for the 49 Modules, this is what I plan to get:


What do you think?

Or I buy a battery from some wrecked car and just buy the extra Module...

So from your stand point, How long do you think a Leaf pack would last if it ratted at 60%? By this I mean how many cycles does it have left?


Yes I do remember you saying this about them being able to be parallel.. sorry for that..
 

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The gen 1 volt modules did come in a 48 nomimal set, I have 4 in series for 1/2 pack nominal 196 volts with the 120 set and the 70 ish set as the other side. There are disconnects under the covers you can remove with a 10 mm socket. Unfortunately, you cant disconnect the cooling plumbing as easily so you're stuck with the assembled module sizes. Which in my case wasn't a deal breaker
 

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The gen 1 volt modules did come in a 48 nomimal set, I have 4 in series for 1/2 pack nominal 196 volts with the 120 set and the 70 ish set as the other side. There are disconnects under the covers you can remove with a 10 mm socket. Unfortunately, you cant disconnect the cooling plumbing as easily so you're stuck with the assembled module sizes. Which in my case wasn't a deal breaker
You are stuck with the modules - but you can re-group them - and because the Volt has them as three "lumps" with water connectors between them you end up with enough water connectors for most configurations
I re-configured mine as two blocks
120834
 

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The gen 1 volt modules did come in a 48 nomimal set, I have 4 in series for 1/2 pack nominal 196 volts with the 120 set and the 70 ish set as the other side. There are disconnects under the covers you can remove with a 10 mm socket. Unfortunately, you cant disconnect the cooling plumbing as easily so you're stuck with the assembled module sizes. Which in my case wasn't a deal breaker
It's not entirely clear what this was supposed to mean - perhaps an example of trying to type on a mobile device - but I think the "120" and "70" are voltages.

Do you mean a 48V (nominal) module or block? None of the Volt modules are 48 V nominal, but the 12S modules are 45 V nominal; the other modules are 6S.

The 9 modules of the Gen 1 are grouped into blocks, which as mentioned are mechanically assembled into blocks which most people leave assembled; however, those don't readily re-arrange into two equal sets to make two parallel strings or a tidy rectangular package, so some do modify a block. Duncan apparently used the stock 42S block and assembled another 42S block from all but one the other modules to match it, building an 84S pack - more details are in his Dubious Device build thread.

This image from mfor1000's 911 project shows the three blocks as they come out of the Volt Gen 1 pack:
120833

  • 3 x 12S + 1 x 6S
    • top left in photo
    • across under back seat in pack car
    • 42S, 158 V nominal
    • 33" long
  • 2 x 12S
    • top right in photo
    • middle of tunnel in pack in car
    • 24S, 90 V nominal
    • 25 1/2" long (including cooling 90 degree outlets)
    • "70ish set"?
  • 2 x 12S + 1 x 6S
    • bottom in photo
    • front of tunnel in pack in car
    • 30S, 113 V nominal
    • 25 1/2" long (including cooling 90 degree outlets)
    • "120 set"?
The Volt Gen 2 modules are different sizes, still in blocks but grouped differently, with the same overall 96S configuration and corresponding nominal voltage.
 

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Discussion Starter #12
So here is my deciding factor question...

If I put together a Nissan pack from 60% Modules. What can I expect from a life expectancy stand point from the pack??
 

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It depends on how they were treated. Modules from Leafs built after March 2013 are heartier than prior, and they get a bit better again in model year 2015.

If they're from Arizona on a car that saw a lot of fast charging and, I dunno, lots of full-throttle pulls in an 100°F day, they'll be worse than a car that lived in Oregon and was usually just plugged in at night, dawdling to the office every day.

I'm not so sure the difference is massive. Put in as much battery as you can stand, and after driving your project for a few years, you'll be able to replace them with better modules for not much money. If you're not buying the whole car, buy the batteries last.

Like, I might be inclined to get a super cheap 2011 pack from wherever, get the project on the road, and worry about longevity later...if you ever finish...because you'd be more likely to finish. I saw some 1st gen leaf packs going for $1000 on eBay. Maybe it was a scam or there was more to it, but lithium batteries simply don't get cheaper than that at the moment.
 

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It's not entirely clear what this was supposed to mean - perhaps an example of trying to type on a mobile device - but I think the "120" and "70" are voltages.

Do you mean a 48V (nominal) module or block? None of the Volt modules are 48 V nominal, but the 12S modules are 45 V nominal; the other modules are 6S.

The 9 modules of the Gen 1 are grouped into blocks, which as mentioned are mechanically assembled into blocks which most people leave assembled; however, those don't readily re-arrange into two equal sets to make two parallel strings or a tidy rectangular package, so some do modify a block. Duncan apparently used the stock 42S block and assembled another 42S block from all but one the other modules to match it, building an 84S pack - more details are in his Dubious Device build thread.

This image from mfor1000's 911 project shows the three blocks as they come out of the Volt Gen 1 pack:
View attachment 120833
  • 3 x 12S + 1 x 6S
    • top left in photo
    • across under back seat in pack car
    • 42S, 158 V nominal
    • 33" long
  • 2 x 12S
    • top right in photo
    • middle of tunnel in pack in car
    • 24S, 90 V nominal
    • 25 1/2" long (including cooling 90 degree outlets)
    • "70ish set"?
  • 2 x 12S + 1 x 6S
    • bottom in photo
    • front of tunnel in pack in car
    • 30S, 113 V nominal
    • 25 1/2" long (including cooling 90 degree outlets)
    • "120 set"?
The Volt Gen 2 modules are different sizes, still in blocks but grouped differently, with the same overall 96S configuration and corresponding nominal voltage.
The modules are easier to juggle than that!
You have to take the steel straps off the top
The blocks are then held together along with the end plates by long threaded rods
The Gen 1 is 7 off 2kwh modules and 2 off 1kwh module
You can treat each module as being interchangeable except the two 1kwh modules are half as long

I used a single "battery" to make my battery -
I could have made it into two "lumps" - one of 3 off 2kwh modules plus the 2 off 1kwh modules
And the other of the 4 off 2kwh modules
But that was too long for my battery compartment

The cross block - the one with the two green straps in the photo has two blank end plates and two middle water connection plates
The other two blocks each have two end plates with pipes on them
So you get the 9 modules
two blank end plates
four end plates with pipes
the two middle connection plates

Converting mine to two "lumps" I used the two blank end plates and two of the end plates with pipes on them
The remaining waterbits are in my just in case box
 

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I think the most important thing to take into consideration is the size and shape of the modules and which design would best fit into your project.
For one car it might be the Volt modules and another it might be the Leaf.
Make up some cardboard templates and try them in the car to see which best suits your project.

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