[ausev] 24V Batteries?

[Brian Lasseter]

On Tue, Sep 29, 2009 at 8:58 AM, David Mark Svetlecic
<davidmsvetlecic at yahoo.com> wrote:
> Since 12V is better than 6V as far as total battery weight, would 24V be
> even better yet than 12V? What are the trade offs?

I would call into question your initial statement... that 12V is
bettery than 6V for total battery weight.  In my browsing of
batteries, you will see the same energy available for the same weight.

So my 1200lbs of 8V batteries gives me 24kwh, just as 1200lbs of 12V
batteries would give you 24kwh, and 1200lbs of 6V batteries would give
you 24kwh of energy.

Since 1200lbs of batteries always gives you the same energy, about
24kwh, what then do you get by choosing 6V, 8V, 12V, or 24V batteries?
  You get a higher total pack voltage which will give you a higher
instantaneous power (W), at the expense of less electrical charge
(Ah).

Or, to put it in terms of "driving experience", you will be able to
drive faster, but you will not be able to drive near as far.  So
choosing a battery voltage is a matter of deciding how you want to
trade off power for range.


I know Erik Bigelow was unhappy with his 6V pack, so we went back to
an 8V battery pack in his Cabriolet.  I can't immediately think of
anyone else who has changed battery sizes in their EV, but I'm sure
there are many other examples.


-- 
TTFN,
Brian "Lasso" Lasseter

"No Sane man will dance."   -Cicero (106-43 B.C.)