Re: [Paddlewise] Electric Pumps ??

From: "Dickson, Dana A." <dana.dickson_at_unisys.com>

> FWIW, and although I don't recommend it, I also tried a 1.2 AH battery with
> a 3 amp draw.  The trial was during a practice session so the battery got a
> workout.  The battery did not fail.  If it had failed I would have used my
> backup manual pump.

If I understand the situation correctly, the failure of the battery would
be in terms of reducing the number of cycles available in its life.
When a battery is ideally cycled (discharged & recharged) it should last
for hundreds or even over a thousand cycles.  Serious repeated discharges
at too high a rate can reduce that to a couple of hundred cycles.  
This failure results in it only producing (IIRC) about 60% or less of the
original capacity.  Given the cost and pollution potential of these 
batteries, extending their life is a good idea.

I've been studying lots about rechargable batteries lately and found that
there are sites (search on Yuasa or Panasonic or just gel cell etc) that 
have even better documents than the one I posted a reference to.  

Today I picked up a 5 Ahr, 12V Yuasa battery (used) for $5 at a surplus
store.  I'll be experimenting with it.  At 2 kg (4.4 lb) it's a brick,
but I hope to find out if it is useful as a general purpose power 
source on trips and not just for the pump.  For example, I can use it 
to recharge other batteries (i.e. AA types, or the battery in a VHF) 
or allow me decadent evenings with a cd player on a long trip.  As long
as I reserve enough for the pump, I should be ok.

I've also done some homework on pumps.  I found that the Attwood 625
submersible draws significantly less power than any Rule pump.  The 
Rule 500 draws 1.9A and the Attwood only 1A, yet it clears the water
over 40% faster.  It remains to be seen whether the claims of the 
manufacturer are realistic.  

Anyone have anything bad or more realistic to say about the Attwood 
before I spend?

Mike


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