I don't want to hijack the discussion, just expand it a bit...

While shopping for a car charger for a Blackberry Storm, both the
Verizon store AND several electronics mega-stores warned me against the
cheap chargers (and at Verizon, only their model would do). Their
argument was that the cheap ones would 'force' more current into the
phone than was good for the battery and severely shorten the life of the
battery.

None of the clerks were up to a discussion of engineering
fundamentals...

However, one service tech who seemed trustworthy did claim to personally
know that the non-Verizon charged units came back with batteries that
wouldn't hold a charge any more. He could only speculate on the
engineering reason.

It would seem unwise to design a phone with the battery directly
connected to the usb +V. Some sort of regulation is required, if only to
prevent exploding LiIon batteries.

There is also talk of 'fast charge' adapters, versus regular. Hmmm.

So,

Is there any truth embedded in this 'street' knowledge?

I can't see how one could 'force' more current into the phone, except if
it was a constant current supply (or maybe +12v on the usb cable), but
that would violate the usb spec. Even then, the internal regulator
should prevent problems. Am I missing something?

How is 'fast charging' accomplished?

Now the funny part. I started using a non-Verizon adapter. It charges
other usb rechargeable things fine. The Storm says it likes it fine too.
No excess heat generation during charge. Done a few times over a month
and suddenly the battery went from 24+ hours on a charge to 12, then 7,
then 3, then 1 hour life per charge over the course of a week or two. I
never had  LiIon degrade like that. It's about a year old.

Not sure if iPhone and Blackberry share the same type supply design (the
Storm seems to need more than a simple cable to charge as does the
iPhone). It seems a lot like cause and effect. I'm not willing to buy
into that until I can see an engineering reason though.

Anyone care to comment?

-Skip

--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.