Re: (ET) cordless electric mower

[bill-wallace att net]

Does anyone else recall White Lightning?  An electric land speed record 
setter in 1999.

>From their website [ http://www.speedace.info/white_lightning.htm ]:

"White Lightning is powered by two electric motors with controllers and a 
complex 420 volt battery pack consisting of 6,120 nickel-metal hydride, AA 
sized batteries."

If memory serves, a more detailed page I can locate off-hand explained the 
choice was based on amps / lb..

Thanks,
Bill

 -------------- Original message ----------------------
From: "David Roden" <etpost drmm net>
> On 24 Jul 2006 at 21:33, David C Robie wrote:
> 
> > NIMHs   -  don't believe the hype.
> 
> Like anything else it depends on what you're doing with them.  Nicads 
> can 
> take overcharge much better and I'd guess that's why the tool mfgs went 
> back 
> to them.  
> 
> Users want fast charges but low tool prices.  The mfgs bundle about the 
> cheapest, crappiest junk chargers they can buy at low bid.  With 
> relatively 
> high charge rates (in some cases) and essentially no charge control they 
> trash NiMH in short order, but nicads can stand this treatment better.
> 
> Self discharge is higher on NiMH but not that much higher!  Cheap cells 
> or 
> failing cells *will* have bad SD though.  I use Nexcell/Powerex/Maha and 
> sometimes Energizer NiMH for my digital cameras.  One of the cameras 
> sits in 
> my briefcase for weeks or months without being used, and only once has 
> it 
> let me down when I wanted it.  As I said, good cells are higher SD than 
> nicad but not by *that* much.
> 
> NiMH is quite decent - better than nicad but not as good as lithium 
> based 
> secondary cells - where you need small size, low weight, lots of energy 
> on 
> board.  Darn few AA size nicad cells will yield a real world 2.2 ah, but 
> NiMH can and does.  (Though high capacity comes at the expense of cycle 
> life.)
> 
> I don't know how useful this exchange is to trakers since I doubt that 
> anybody here is going to use NiMH in his tractor - but we do have a 
> couple 
> of people using nicads.  Flooded ones, that is - not AA cells!
> 
> 
> David Roden - Akron, Ohio, USA
> 
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>  
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