Hi Steve,
Whereas Saft's literature says that they make rechargable lithium cells, it looks like the bulk of their products are one use items (non-rechargable). Doing a quick search, they do have high energy density by weight, however, there are some limitations to the cells. The high energy version of the "C" cells will sustain a C/4 discharge rate, they should last around 3-4 hours at that rate. Their regular "C" cells will sustain only a C/50 discharge rate.
So if one bought a bunch of these cells, 15 cells in series would create a 7.7Ah x 48V nominal (54V actual) battery. 20 groups in parallel of 15 cells in series (300 cells total) will create a battery bank that specs to 154Ah x 48V (7.3kWh) and the whole package weighs only 40 lbs. Compare that to my prismatic Lithium cells that rate to 8kWh and weigh 200 lbs. The draw on the Saft batteries should be kept to less than 39A (about 1900W). My batteries will sustain a 480A draw without damage.
Once the Saft batteries were discharged, you would throw them away. The bare Saft cells would cost $6900 though the vendor that I found online. My prismatic cells cost $3400 shipped including simple BMS. My cells can be recharged.
I guess that one could put together a one-time only emergency battery pack (they do have a very good shelf life) but that would be too expensive for my budget. :)
If anyone can find specs on Saft rechargable lithium cells, please post the link and I can do the math for a rechargable pack....
Thanks,
Eric
--- In electricboats@yahoogroups.com, Steve Dolan <sdolan@...> wrote:
>
> I was just talking to a guy who can get me battery packs from a company called Saft. He even gave me a couple "C" cells t play with. Most of their stuff looks a little dangerous but since we were talking batteries I thought I would see what the brain trust thought. Yes they are expensive!
>
> http://www.army-technology.com/contractors/electrical/saft/
>
> Steve in Solomons MD
>
No comments:
Post a Comment