# Best BMS for Tesla modules



## DrGee (Aug 22, 2018)

I've finally decided to use Tesla modules for my conversion. The plan is for a 50kwh battery pack, so this will need 10 Tesla modules in series (240V total).
Is there an off the shelf BMS like Orion that I can use for this arrangement. Or should I go for one of the open-source products that require more skill to configure? I'm a complete newbie to the ev world, but have a basic knowledge of electronics and a keen interest in cars and computers.


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## cricketo (Oct 4, 2018)

Zeva can do it, you'd need multiple modules for your configuration. http://www.zeva.com.au/index.php?product=133


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## boekel (Nov 10, 2010)

DrGee said:


> I've finally decided to use Tesla modules for my conversion. The plan is for a 50kwh battery pack, so this will need 10 Tesla modules in series (240V total).
> Is there an off the shelf BMS like Orion that I can use for this arrangement. Or should I go for one of the open-source products that require more skill to configure? I'm a complete newbie to the ev world, but have a basic knowledge of electronics and a keen interest in cars and computers.


Using a different bms requires much more work and skills than using for example Tom de Bree's SimpBMS, you only need comm's wires and the tesla bms board on the modules are perfect.


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## DrGee (Aug 22, 2018)

boekel said:


> DrGee said:
> 
> 
> > I've finally decided to use Tesla modules for my conversion. The plan is for a 50kwh battery pack, so this will need 10 Tesla modules in series (240V total).
> ...


Fantastic! I'll take a look at Tom de Brees' SimpleBMS asap.


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## DrGee (Aug 22, 2018)

cricketo said:


> Zeva can do it, you'd need multiple modules for your configuration. http://www.zeva.com.au/index.php?product=133


Zeva looks good, but it looks like I'd need more than 350 Zeva module V3's for the 4440 cells in the 10 Tesla modules I plan to use.


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## brian_ (Feb 7, 2017)

DrGee said:


> Zeva looks good, but it looks like I'd need more than 350 Zeva module V3's for the 4440 cells in the 10 Tesla modules I plan to use.


The actual cell count doesn't matter, since a group of cells connected in parallel are a single cell as far as the BMS is concerned. A 16-module Tesla Model S/X battery needs 96 BMS channels, so that would be eight of the Zeva modules (at 12 cell levels each, which would be two battery modules each); the proposed 10-module battery would need five Zeva modules. Right?


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## DrGee (Aug 22, 2018)

brian_ said:


> DrGee said:
> 
> 
> > Zeva looks good, but it looks like I'd need more than 350 Zeva module V3's for the 4440 cells in the 10 Tesla modules I plan to use.
> ...


That makes sense. Tesla modules are 74p6s I believe. 10 modules will be 60 parallel sets. Using one Zeva module per 12 cell levels means I'll need only 5 Zeva V3's as you calculated. That's a relief. How tricky is it to pull out Tesla's built in bms and install the Zeva?


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## cricketo (Oct 4, 2018)

DrGee said:


> That makes sense. Tesla modules are 74p6s I believe. 10 modules will be 60 parallel sets. Using one Zeva module per 12 cell levels means I'll need only 5 Zeva V3's as you calculated. That's a relief. How tricky is it to pull out Tesla's built in bms and install the Zeva?


Makes me wonder... maybe Tesla modules isn't what you actually want ?  How about Leaf or Volt modules instead ?


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## DrGee (Aug 22, 2018)

cricketo said:


> DrGee said:
> 
> 
> > That makes sense. Tesla modules are 74p6s I believe. 10 modules will be 60 parallel sets. Using one Zeva module per 12 cell levels means I'll need only 5 Zeva V3's as you calculated. That's a relief. How tricky is it to pull out Tesla's built in bms and install the Zeva?
> ...


I've quite a bit about the lack of longevity in Leaf batteries. I think Nissan now have a buyback programme for owners whose batteries are giving up before reasonable guarantee period. I thought about Volt modules, but they have such an awkward shape. If I pull them apart, I then lose both the system for keeping them tightly compressed as well as the liquid cooling system. Do you know if anyone has any workarounds for these two issues?


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## cricketo (Oct 4, 2018)

Leaf has longevity issues are due to lack of cooling. Seemed like it was an issue only in extreme hot weather found in a few states. If you know where your modules come from, may be less of an issue. What's also important, Leaf modules are the easiest to work with - even if some cell starts giving you trouble, you can easily swap out the module. Not so much with a cell in a Tesla pack.

Yeah, Volt modules may be quite tricky if you have space constraints.


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## DrGee (Aug 22, 2018)

cricketo said:


> Leaf has longevity issues are due to lack of cooling. Seemed like it was an issue only in extreme hot weather found in a few states. If you know where your modules come from, may be less of an issue. What's also important, Leaf modules are the easiest to work with - even if some cell starts giving you trouble, you can easily swap out the module. Not so much with a cell in a Tesla pack.
> 
> Yeah, Volt modules may be quite tricky if you have space constraints.


Thanks Cricketo,
I'm going to have another look at Leaf modules.


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## SWF (Nov 23, 2007)

DrGee said:


> That makes sense. Tesla modules are 74p6s I believe. 10 modules will be 60 parallel sets. Using one Zeva module per 12 cell levels means I'll need only 5 Zeva V3's as you calculated. That's a relief. How tricky is it to pull out Tesla's built in bms and install the Zeva?


If you decide to go with Tesla modules and use the ZEVA BMS, have a look at page 4 and 5 my build thread that has some photos of that combination. My modules did not come with the Tesla slave boards, so I had to start from scratch. If the modules did have the Tesla slave boards, I may have decided to go with a system that made use of the Tesla boards, but the ZEVA system also works well.


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## DrGee (Aug 22, 2018)

SWF said:


> DrGee said:
> 
> 
> > That makes sense. Tesla modules are 74p6s I believe. 10 modules will be 60 parallel sets. Using one Zeva module per 12 cell levels means I'll need only 5 Zeva V3's as you calculated. That's a relief. How tricky is it to pull out Tesla's built in bms and install the Zeva?
> ...


I'm torn between using;
1) 100 Leaf modules, with air cooling for the pack via a beefed-up a/c system. 
2) 10 Tesla modules with the stock liquid cooling. 
I can get the Leaf modules for about $7,000, but the Tesla set would be at least $12,000. Perhaps the price would have fallen by the time I get to that stage of the build..


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