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Old 06-23-2010, 02:29 PM   #7 (permalink)
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Originally Posted by Nevyn View Post
I already have about 40 Li-Ion cells. Maybe 4-6 of them are bad?
You may be underestimating how very large a car's battery pack is compared to that of a laptop. How many amp-hours do you have left? The stock pack is 6.5Ah*144V, or 1KWh, and ideally you'd want to improve on that.

The other thing you need to know about your cells is: how fast can they discharge? The stock cells can handle 100A discharge and 50A charge. Most laptop cells are probably capable of about a tenth that.

You'll need about 50 good cells to match the voltage of the stock battery pack, or about 16 cells (all capable of about 120A) to supply 48V to an Enginer 5kW DC/DC converter.

And then there is the question of a BMS.
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