Re: z50 battery oddity

["Brian Bezanson" <bbezanson%gmail.com@localhost>]

> What I don't know, however, is whether the charge control circuit is in the 
> battery itself or if >it's in the z50. In any case, the long and the short of 
> it is that yes, you can replace the Li-ion >cells, but the cells aren't 
> readily available to consumers (I have seen them online and in >surplus 
> stores), and you run the risk of causing a toxic metal fire if you screw 
> things up :P

Each battery module has to keep track of its own cells' degradation
over time (if you treat old cells like new ones, you'll severely
overcharge them, which would be *bad* for Li-ion), so there's some
intelligence built into the pack.

Also, if you have a Li-ion pack that contains a bunch of cylindrical
cells, they're almost certainly 18650s, which are a little bigger than
AAs.  Li-ion cells are, of course, electrically incompatible with any
chemistry sold in AA packaging.  Batteryrefill.com will crack open
your pack, replace those cells, put it back together, and ship it back
to you.  It's probably worth it to let them do it, even if you could
get your own cells, for a couple reasons:
1. They already know how to open and reassemble your pack without
damaging it too much.
2. They have the equipment to make good welds onto the batteries.
Spot welders aren't cheap, and if you try to attach a tab to a cell
with a regular soldering iron you'll almost certainly heat the cell up
enough to damage it, if not set the damn thing on fire.
3. I think they have a warranty.

As for running from 12V lead-acid, I've run mine from a
straight-through lighter socket adapter (with the engine off, so just
the battery voltage) plugged into the AC adapter port.  It won't
charge its own battery from that, but it runs happily.  That's
probably easier than hacking plugs into the AA case or an old dead
battery pack.

Brian

>  Hope this explains a few things!
>
>
>  ~k
>
>  > Date: Mon, 31 Mar 2008 11:18:48 -0500
>
> > From: elijahr%gmail.com@localhost
>  > To: piper_the%hotmail.com@localhost
>  > Subject: Re: z50 battery oddity
>  > CC: port-hpcmips%netbsd.org@localhost
>  >
>
>
> > On Mon, Mar 31, 2008 at 10:52 AM, Khoa Tran  wrote:
>  >>
>  >> Interesting thought! But the z50 batteries are definitely li-ion, 
> unfortunately.
>  >>
>  >
>  > I know very little about rechargeable batteries. Would the z50 using
>  > li-ion cells make a difference?
>  > If there were indeed AA li-ions in the battery pack, why couldn't they
>  > be swapped out for something like NiMH batteries? I am under the
>  > impression that AA batteries have a standard voltage and amperage so
>  > are modular, though based in your comments, I am starting to feel that
>  > this is not the case.
>  >
>  > Additionally, it seems that many laptop batteries are repackaged
>  > li-ion AA batteries: see http://lowendmac.com/musings/06/0908.html
>  > So, couldn't one just swap for some higher quality li-ions, if the
>  > type of rechargeable battery does indeed matter?
>  >
>  > Cheers,
>  > Elijah Rutschman
>
>
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