Re: (ET) cordless electric mower

[David C Robie <mycroftxx1 juno com>]

Dave

NIMHs   -  don't believe the hype.  Engineering specs vastly understate
the self-discharge of these dingi.  Note the love affair mfgrs of
portable power tools had with em bout 3 -4 yrs ago.  Now almost none are
using nimh, gone back to good ole nicads (which have been improved to
mostly  solve their 'memory' problems.
Nimh scenario typical;  charge both batteries for your Edrill.  Use the
drill a bit. (no pun intended) and not use it again for  a couple weeks. 
Pick it up, batt is real weak.  Put in the other. !@##$ real weak too. 
Seems to be like 1/30 per day loss.  
    Can see them with constant tiny charge stuff like emergency lights
but at any rate (another no pun) they inherently waste power in these
days of priority need to use less of it to ramp down peak oil and global
warming.  

Carry along backpack for Emower?  Like marching in the mud I wouldn't
want to do it.  How about a 1500 watt continuous 12V -120ac inverter
clipped acrosss 2 0f the Etrak batts - then 10 minutes (or whatever)
later across another 2, and  then later another 2?  (to discharge em all
equally)  That's how my 'emergency power' for hurricanes etc system works
but with an 850W continuous inverter and a separate 500W also and 2
Etraks that are most always fully charged (by solar).  That way my gas
generator only has to run the furnace or refrig, both intermittent duty.
(found out a long long  time ago that gasoline station pumps are
electric, no gas available during big power outs - my storm solution uses
very little of it, and only a 1500W 40 yr or so old gas generator.

YAH those interconnects.  I can also see you troubleshooting the thing
when an individual cell or 2 shorts thru and lowers your pack voltage, or
opens up. There was a stand up Escooter built a few yrs back that had a
mess of nimhs in series parallel under the floor.  Grat design. All the
battery weight all the way down.  Logical.   But that was their unforseen
problem.  Lot of batteries failed in warranty, lotta troubleshooting and
repl time put the company in the poorhouse.  Think they are gone now.


Dave
Weymouth MA





On Mon, 24 Jul 2006 02:29:08 -0400 "David Roden" <etpost drmm net>
writes:
> On 22 Jul 2006 at 21:14, David C Robie wrote:
> 
> >  took one of those B and D type mowers, put a 12V battery on it 
> and a
> > 1500 watt 120V DC/AC inverter.
> 
> A couple of times when I've seen a good deal, I've been tempted to 
> buy 100 
> 1.2 volt D-size NiMH or high capacity Nicad cells. I'd put them in a 
> 
> backpack, not on the mower itself (too awkward and heavy).  The main 
> things 
> that stop me are (1) I'd be scared to charge that many NiMH cells in 
> series; 
> and (2) I'd have to spend the rest of my life hooking up the 
> interconnects.
> 
> It might be better to put an inverter on the ET and use that to 
> power the 
> push mower when I'm far from the house.
> 
> BTW, thanks for the tip on the hammer-on caps.  There's an Ace 
> Hardware on 
> my way to work; I'll stop there this week.
> 
> 
> David Roden - Akron, Ohio, USA
> 
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