Sealed lead acid batteries in old PBooks?

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DrBunsen's picture
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Sealed lead acid batteries in old PBooks?

I'm wondering about using 6 and/or 12V sealed lead acid burglar alarm batteries in old 'books, like the 180, Duos, 520/540 series. There are some small ones available that would suit the 520s especially, say a pair of 6V in each side in series.

I understand that the charge curves would all wrong for the onboard controller, and that I'd need to match/ limit voltages. Would I be able to take a line straight from the 24V in to a small charge control circuit, and then from the battery to the lappy via a regulator.

Any opinions? Am I likely to find/make a charger board small enough to fit, say under the trackball/between the two front battery bays?

How can I find out the battery voltage for each laptop type, bearing in mind that their existing batteries are all dead?

eeun's picture
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Joined: Dec 19 2003 - 17:34
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Battery voltages

Google around for replacement batteries for each 'book you're looking to modify.
Most resale places will list the battery's voltage and amperage.

The 520 book comes up as:
Chemistry: NiMh
mah: 2100
Volts: 9.6

And for the 180 (third party extra capacity):
Chemistry: NiCd
mah: 3200
Volts: 6

If you don't already have the lead-acid batteries, it would be better to re-cell the existing batteries with the correct type of cell. You can find batteries on ebay that come with soldering tabs attached.

DrBunsen's picture
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Better, yes...

... but cheaper, perhaps not. I'll look into the prices of the correct batteries. I might be able to pick up some RC car battery packs and dismantle them.

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