Re: (ET) Lithiums in an E15

["David Roden" <etpost drmm net>]

On 4 Nov 2010 at 13:51, Charlie wrote:

>  guess you'd want to rewire them as parallel rather than series
> strings, though; the Prius runs high voltage. 

NiMH isn't really a very practical choice for an application requiring 
more 
than about 10ah of capacity, because they're deliberately not made in 
larger 
capacities than that.  (Actually I think the limit by Cobasys license 
terms 
is 25ah, but any size larger than 10ah is pretty hard to find.)  

Thus practical EV or ET capacities require paralleling strings.  This is a 
problem.

NiMH batteries can be discharged fairly stably in parallel, but they don't 
play nice when charged in parallel.  You need a separate charger for each 
string.  You also need contactors to separate the strings for charging and 
connect them for running.  Both of these add complexity and expense.

You might gain some cycle life and get longer runtime in cold weather, but 
at quite a substantial cost.  And you lighten a tractor that you want to 
be 
heavy!  I don't think it's worth it, but I suppose others might.


David Roden - Akron, Ohio, USA

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