Re: [Paddlewise] GPS and ham

From: "john" <jrhauer_at_attbi.com>

> NiMH, I hear rechargeable alkaline are the real way to go.

My experience, and that of several others on sci.geo.satellite-nav, is
that rechargeable alkaline (RA) are not worth the time and money.  You 
can't fully discharge an RA battery without ruining it, so you have to
monitor it and stop using it at about 50% depth of discharge.  This
alone makes it less than fully useful.  I'm much more impressed with NiMH.

> You know they may last longer, but I wouldn't start the day with partially
> used batteries. So, that's why I said, "They last about a day." The little
> meter on the unit can not be that reliable. And, I don't know what the usage
> curve is, so why risk it?

You have to have a battery monitor that is set for NiMH and not all GPS units
are so constructed.  

I think that the self-discharge problems are somewhat overstated with NiMH.
They certainly discharge about twice as fast as NiCd, but I find that 
their extra capacity makes up for it.  If it has 50% more capacity than
NiCd but discharges 30% in a month, you're still ahead.  Certainly they
aren't as good as alkaline for shelf life, but regular use and occasional
topping up (something that has much less effect than topping up NiCd)
solves it.  I also make sure I always carry spares.  That's one reason
that all the electronics I use in kayaking (GPS, camera, flashlights etc)
are standardized on AA batteries - standard, interchangeable spares.

Mike
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