Making my own PowerBook battery

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Joined: Jul 20 2007
Posts: 4
Ahhh . . .

Excellent! That makes a lot more sense. I haven't actually taken the cells out of the battery yet, so I can't see the parallel/series connections, and the cells aren't individually labeled specswise. But having each at 1.2V, 1000mAh makes much more sense. (They are Li-Ion, by the way. But when I googled the part number, I got only about 5 sites, all in different languages, so I wasn't able to learn much about the cells that way.)

Unfortunately, my question still remains. Will it cause any problems if I were to drop from nine to six cells, and double the capacity of each? I admit that I don't really know how the battery circuitry is "managing" the cells, if that even affects anything significant.

Actually, my dad got this computer a few years before I entered grade school. He was resuming college for a further degree after being a missionary in Kenya for decade. He at first got the faster version of the laptop, but it scared him when the text was scrolling by too fast to read in DOS. So he returned it and got the slower one Tongue

dankephoto's picture
Joined: Dec 20 2003
Posts: 1900
re: Ahhh . . .

AFAIK, LiIon cells are all 3.6v, the chemistry apparently requires it. I've never heard of or seen 1.2V LiIon cells, that's why I suggested the cells might actually be NiMH or NiCad.

When was the machine in question current?

dan k


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DrBunsen's picture
Joined: Dec 20 2003
Posts: 946
Re: D cell External Battery Pack

macfreak4 wrote:

I'm building a very large D cell pack for long 13+ hrs international plane flights.

I hope you remember to get to the airport an extra two hours early for the inevitable grilling by Homeland Security


Damn the Torx screws, full speed ahead!
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Joined: Jul 20 2007
Posts: 4
Toshiba T3400

It's a 1993 laptop, I believe.

And indeed, the batteries are definitely lithium ion. I took the battery apart last night (hopefully I didn't break anything important) and the parallel/series arrangement confirms that each cell must be 3.6V, despite an utter lack of labeling as such.

Joined: Jul 20 2007
Posts: 4
Curiousity killed the cat

All right, so after reading a bit more I'm pretty confident that replacing the 18650 cells with 18650 cells of twice the capacity shouldn't cause any problems (though confirmation on this would be appreciated).

But because I'm just too darn curious, would it be possible to rig up regular, non-rechargeable (let's say Energizer) AAA batteries where the Li-Ion batteries used to be? I've discovered that with 7, I can achieve 10.5V, which is probably close enough to 10.8V, and I can get them to physically fit in the case, and even to comply with the existing electronics in the case. The question is, will this work?

cwsmith's picture
Joined: Oct 13 2005
Posts: 699
So long as you never, [i]ever

So long as you never, ever have the battery in while running off AC power ...


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Joined: Oct 14 2008
Posts: 1
external battery

This might be a bit of the original post, but was wondering if someone can help me with this:
I work in the film industry and on location we always have lots of block lead acid batteries around. They are 12V and around 10Ah. I was wondering, if i do an adaptor to the battery terminal of a powerbook G4 12" (removing the laptop's battery and connecting directly to the laptop's battery connector, not the power adaptor plug), would this work to power my laptop? What is the minimum Ah battery i should use? Which of the six terminals should i plug it? (+ and -). No need to recharge with the laptop, will do it with a separate charger.