Re: [Paddlewise] rechargeable batteries

Elaine,

What matters is how the voltage of the battery changes as it is
discharged.  Alkaline and NiCad batteries keep their voltage almost
at the same level (1.5V and 1.2V respectively) until they run out. Then
their voltage drops 0 very quickly and whatever you are running quits
working all of the sudden.  The curve looks like this

1.5 V ---------      (1.2 in the case of NiCad)
               \
                \
0 V              -------

With other batteries, like dry batteries, the voltage drops slowly
as the battery is used until it gets to the point where the voltage
is too low to handle the load of whichever machine you are operating.

1.5 V --             
        \----
             \----
                  \------
                         \-----------
0 V
           
Many electronic devices, specially those that use digital technology,
can not operate with batteries at low voltage.  Hence the requirement
of batteries that keep the same voltage level throughout their life.

This is, by the way, the reason why I recommend dry cell batteries
for electric pumps--you can tell when the batteries are low and
they still have a long time to go before they die out, versus
giving you the impression that they are fully charged and then
dying out all of the sudden when you need them the most.

happy paddling,
- Julio

> 
> Hi- I try to send this to John at Raytheon but my mailer can't cope today:
> 
> I note the Ray102 book says to only use alkaline or NiCad batteries in the
> battery holder. Does that mean you can't use the Ni-metal hydride
> batteries (the ones that, as I understand it, don't have a memory so they
> can be recharged without being fully discharged)? e
> 
> Elaine Harmon - eilidh_at_dc.seflin.org - eharmon_at_cs.miami.edu
> 


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