[Tfug] OT: Batteries

[Bexley Hall]

Hi Don,

> I guess you'd have to weigh the volume of sales to determine if 
> a custom battery would make sense. Otherwise the cost would become
> prohibitive. Also

<frown>  It's never as simple as that.  :>  I.e., custom
batteries can give you capabilities that you couldn't get
otherwise (i.e., the "cost" of a non custom battery can
be more than that of a custom -- depending on your needs)

As a silly example, imagine making an electric car using
COTS batteries...

> you'd have to consider the cost of the device. After about
> $10 I don't want to consider anything disposable and the 
> higher it goes the less 'disposable' it becomes.

Are you thinking of the *battery* or the entire *device*?
I.e., a $10 device wouldn't bother me to "replace" with
some regularity -- assuming I get $10 of use out of it!
(I have a rechargeable flashlight that just promoted itself
to this condition recently... do I spend $10 on the NiCds
that it needs or replace the entire flashlight??)

OTOH, if we're *just* talking about the battery, then I
would have to evaluate it in the context of the total
device cost.  E.g., the $10 -- $9.46 plus tax -- for the
flashlight's NiCds seems excessive given the flashlight
probably only cost $10 to begin with (though the replacement
batteries will be much higher capacity if I go that route).
OTOH, I could make the decision regarding a $10 battery in
a $1000 laptop in a lead pipe cinch!

You don't *want* to consider it as disposable.  But, if
you had no choice in the matter (i.e., no other products
like it; other products are more expensive/worse features;
etc.) would this be a deal breaker?

I.e., I am amazed at how casually people treat their cell phones.
As if it was a piece of clothing to be replaced as styles
change, etc.  (to me a phone is a means of communicating
when/where *I* want, not a "fashion statement"  :> )

> If you went the disposable route you'd also have to build in
> some protections to insure the device didn't discharge accidently
> by being left on unintentionally, etc. Have you considered a fuel
> cell or solar rechargeable? ;)

If you allow the user to replace the batteries, you also need
to protect against battery reversal, etc.

If you *charge* a battery (replaceable or otherwise), then you
have to deal with the complexity of the charging circuit,
estimating charge completion, etc.

I haven't been able to sort out how vendors make this decision.
I see some devices that I *think* should be rechargeable (e.g.,
handheld GPS) that aren't.  And others that I don't think
merit that capability that *are* (e.g., GPS for car).

<shrug>