Re: Dead 140 - battery rebuilding

[Grizzly]

Hello Martin:

martin wrote:
> 
>  Incidentally, does anyone know how to open up a PB 1xx battery pack
>  without damaging it? Or with a minimal amount of damage?
> 
>  And does anyone know an approximate average Amp-Hour rating for a
>  normal 6V lantern battery?
> 
> I can see where you're going with this, cuz I've been down this path with my
> own PB145. I rebuilt 3 batteries for it, and designed a power convertor for
> the car that converts the 12VDC to very clean 7.5VDC @ 3A so it can recharge
> in the car while I'm using it. Cool huh.

Extremely cool!  Could I get the design for the car power inverter but
in a 16, or 15V version?

O.K., I'll come clean.  What I would really like is the same basic
design, but with a variable voltage control.  Say, from 7.5 VDC to 16
VDC.  I'm willing (and actually want to) build it and do some (or all)
of the design myself, but I do need some help to get started.

If I am asking too much, I understand, but I would like to see the
design of your auto power supply at the very least.

Sincerely yours, Grizzlygiant

-- 
PowerBooks is sponsored by  and...

  Small Dog Electronicshttp://www.smalldog.com   | Enter To Win A |
  -- Canon PowerShot Digital Cameras start at $299   |  Free iBook!   |

  Support Low End Mac 

PowerBooks list info:   
  --> AOL users, remove "mailto:";
Send list messages to:  
To unsubscribe, email:  
For digest mode, email: 
Subscription questions: 
Archive: 

Using a Mac? Free email & more at Applelinks! http://www.applelinks.com

Re: Dead 140 - battery rebuilding

[martin]

 Incidentally, does anyone know how to open up a PB 1xx battery pack
 without damaging it? Or with a minimal amount of damage?

 And does anyone know an approximate average Amp-Hour rating for a
 normal 6V lantern battery?


I can see where you're going with this, cuz I've been down this path with my
own PB145. I rebuilt 3 batteries for it, and designed a power convertor for
the car that converts the 12VDC to very clean 7.5VDC @ 3A so it can recharge
in the car while I'm using it. Cool huh.

Best way to open the cases is to scribe around the label face of the pack
using an Exacto knife with a new blade. Just follow the indent around the
label. The trick is to keep cutting around and around until you break
through, NOT try to cut through in one pass. Just be patient. You can switch
to a heavier knife if you're impatient, but you'll end up with a wider cut
which won't look as good later. Once you can cut off the face, just tease
out the cells, and replace them with equal-or-higher rated tabbed cells.
I personally like to leave the packs open, as the cells fit in fairly snugly
and I can change them easily next time, but you could pot them in silicone,
which you just pile in there like meringue, and slice off nice and clean
after it dries (with a sharp blade, or it'll snag). Even comes in gray!  OR
you can glue the face back into place (again silicone is best. While I don't
like to use it for glueing, in this application it's ideal, because of it's
insulating quality, and because it's easy to remove when you want back in).

As I recall, you need 4/5A format cells. The best deals these days are on
NiCd, which is almost as good as the much-hyped NiMH ( I use both, and was
somewhat ... underwhelmed with the NiMH for the extra cost. More important
is to snag the highest Amp/Hour rating you can find ).

I've tested the current draw on my 145, and it draws about 3A on startup,
which levels out to just over 2A when running (backlight and HD on), so you
need a 3A or better supply. You're right in guessing that you can get away
with 6V, but you'd need something like a lead-acid motorcycle battery. You
probably won't even get it to start with a 6V lantern battery (they are
designed for long life at low-moderate current, sorry I don't have the
actual A/hr rating). All things considered, the 100-series Powerbooks are
about the easiest to power, because their voltage is under 12V, and they
only require a single voltage. Any supply between 6 and 8 VDC at 3A or
better will do, although ideally it should be regulated and heavily filtered
(which is why I built the car supply).

Good luck in your battery-rebuilding. Sorry about the long post, but it's a
subject that comes up a lot, so I figured others might also want the info :)

m  



-- 
PowerBooks is sponsored by  and...

  Small Dog Electronicshttp://www.smalldog.com   | Enter To Win A |
  -- Canon PowerShot Digital Cameras start at $299   |  Free iBook!   |

  Support Low End Mac 

PowerBooks list info:   
  --> AOL users, remove "mailto:";
Send list messages to:  
To unsubscribe, email:  
For digest mode, email: 
Subscription questions: 
Archive: 

Using a Mac? Free email & more at Applelinks! http://www.applelinks.com