# Z4 BMW conversion



## schlepers (May 30, 2008)

If I wanted to use the A123 batteries, what motor would be good?

I wanted to get at least 100mph and 100-150 mile range. 

What motor would be good, I was thinking a DC warp?

Controller?

How many batteries?

Any rough estimate how much it would cost in parts?

thx.


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## gklugie (Jun 26, 2008)

I am new to this, but I respectfully think your expectations are very high.

1. donor car too heavy
2. performance/endurance goals very high

I suspect the cost would be prohibitive and the sheer volume of batteries required may exceed vehicle capacity.

I hope I am incorrect. I also hope you are rich!


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## Manntis (May 22, 2008)

added to which, a123 batteries aren't available in large quantities without paying through the nose and, even if you do wrangle a supply, that's a lot of welds over many, many cells. Then the problem of a BMS rears it's ugly head.


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## rctous (Jun 18, 2008)

Definately AC motor not DC , an AC motor is about 50% more efficient,,cost around 2-3 K controller about 3500 bucks+ http://www.electroauto.com/catalog/price-pts.shtml charger and BMS I willl guess about 8-10K. Batteries , well we import them directly from Enerland in Korea in 3000 pc qty's and not to give my cost away but lets say in that qty they were between 10-15 bucks each. You would probably need a very high voltage system ( lets keep it easy) and say you did a 330 volt system (nominal voltage of an A123 cell is 3.3V) 100 cells in series will get the voltage you need and you would probably want 200+ total AH (lets call it 230AH) (as the A123 cells are 2.3 AH each) thats another 100 cells in parallel so total cells would be 10,000 cells at 70 grams each ( for weight)(1545.93 pounds) each cell measures 1.03" in diameter and 2.625 in length,,,, on the low side 10,000 cells would cost about 100K on the higher side 150 K this does not include the labor to assemble all the modules etc. My guess is that this would pretty easily do what you want it to do perhaps more. This is high perhaps but you can reduce it with the #'s here as they are accurate.

B


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## schlepers (May 30, 2008)

rctous said:


> Definately AC motor not DC , an AC motor is about 50% more efficient,,cost around 2-3 K controller about 3500 bucks+ http://www.electroauto.com/catalog/price-pts.shtml charger and BMS I willl guess about 8-10K. Batteries , well we import them directly from Enerland in Korea in 3000 pc qty's and not to give my cost away but lets say in that qty they were between 10-15 bucks each. You would probably need a very high voltage system ( lets keep it easy) and say you did a 330 volt system (nominal voltage of an A123 cell is 3.3V) 100 cells in series will get the voltage you need and you would probably want 200+ total AH (lets call it 230AH) (as the A123 cells are 2.3 AH each) thats another 100 cells in parallel so total cells would be 10,000 cells at 70 grams each ( for weight)(1545.93 pounds) each cell measures 1.03" in diameter and 2.625 in length,,,, on the low side 10,000 cells would cost about 100K on the higher side 150 K this does not include the labor to assemble all the modules etc. My guess is that this would pretty easily do what you want it to do perhaps more. This is high perhaps but you can reduce it with the #'s here as they are accurate.
> 
> B



So the battery is still an issue? How are they going to make that Saturn Sky for so cheap? It's roughly 25k for parts and labor excluding the car. Wouldn't one be able to do something similar but with a different car?


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## TheSGC (Nov 15, 2007)

Saturn will probably rely on large bulk orders to keep prices down on the batteries. Some distributors will offer discounts on bulk orders of batteries, but the catch is that you need many people to get the cost down and the batteries all have to ship to a single address. 

For example, Everspring will give you a 40% discount if the purchase order is for 1 million Ah or more. That's a lot of cells and probably needs 30 or so individual buyers to get the discount. Also A123 Systems has not been too willing to sell to individuals in the past, just large orders to companies like DeWalt and I also think Tesla. Some places have "developer" cells that cost a lot because it's a small 2-4 cell kit.


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## schlepers (May 30, 2008)

*http://tinyurl.com/yuqvvu*

What about with these firefly batteries?


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## schlepers (May 30, 2008)

schlepers said:


> *http://tinyurl.com/yuqvvu*
> 
> What about with these firefly batteries?


Or are there any other type of lithium batteries that I can get for less then 20k?


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## TheSGC (Nov 15, 2007)

schlepers said:


> Or are there any other type of lithium batteries that I can get for less then 20k?


The only other lithiums are the LionEV cells, which is also sold at CloudEV, and the Thundersky LFP, and those can be ordered through Everspring and they can offer discounts if you get enough. Maybe 5-15% depending on the cells. 

I am looking forward to those Firefly Oasis batteries, but all I can find is that they will have a $400 price tag per battery.


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## Rboogie360 (Jun 20, 2008)

I'm a newbie just reading up as much as I can and wondering what you guy's think about this battery pack. Just curious why these aren't mentioned in threads discussing battery options. Can anyone give me their thoughts.

http://www.electricwheelsinc.com/batteries.shtml


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## Manntis (May 22, 2008)

Rboogie360 said:


> I'm a newbie just reading up as much as I can and wondering what you guy's think about this battery pack. Just curious why these aren't mentioned in threads discussing battery options. Can anyone give me their thoughts.
> 
> http://www.electricwheelsinc.com/batteries.shtml


You'll see LiFePo bateries discussed all the time here - or did you mean this specific brand?


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## Rboogie360 (Jun 20, 2008)

I apologize. Newbie here. I guess I haven't read enough. How do you feel about LiFePo? And this brand?


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## Manntis (May 22, 2008)

Rboogie360 said:


> I apologize. Newbie here. I guess I haven't read enough. How do you feel about LiFePo? And this brand?


I'm using LiFePo (lithium Iron Phosphate) batteries myself - but not this brand.


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## Whitey_87 (May 30, 2008)

Sorry to revive this thread but Manntis:

Do you have pictures or a write up of your conversion? I would like to run a lithium pack also but am clueless as electronics go so I am worried about a BMS. 

As a general question, do the Dewalt Lithium packs have the BMS on the battery or is it in the charger - my current understanding leads me to think the BMS is on the battery to regulate discharging as well as charging.

Thanks.


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## schlepers (May 30, 2008)

TheSGC said:


> The only other lithiums are the LionEV cells, which is also sold at CloudEV, and the Thundersky LFP, and those can be ordered through Everspring and they can offer discounts if you get enough. Maybe 5-15% depending on the cells.
> 
> I am looking forward to those Firefly Oasis batteries, but all I can find is that they will have a $400 price tag per battery.


What size are you going to put in your beamer? How much will it cost??


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## schlepers (May 30, 2008)

What motor would be good to give it good speed? I haven't seen too many AC motors out there.


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## rctous (Jun 18, 2008)

Whitey_87 said:


> Sorry to revive this thread but Manntis:
> 
> Do you have pictures or a write up of your conversion? I would like to run a lithium pack also but am clueless as electronics go so I am worried about a BMS.
> 
> ...


The BMS system is on the battery packs in the Dewalts.

Brian


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## Whitey_87 (May 30, 2008)

rctous said:


> The BMS system is on the battery packs in the Dewalts.
> 
> Brian


Do you know if that BMS can handle the discharging requirement of an EV?


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