Joshua G Senecal wrote:
In thinking about a power source for my recently acquired DSW-40, I
realized that the Lithium-Ion batteries in my laptop (PowerBook G4)
might be an ideal solution: small, plenty of power, within the
DSW-40's power requirements (14.1V), and I don't need to buy a
charger--I can just use the laptop.

Has anyone used laptop batteries for powering their gear? And if so,
will you offer some practical advice/tips on using them? I'm
concerned that there may be some difficulties, because modern laptop
batteries aren't just power cells; there's some control circuitry and
whatnot in there too.

Li-Ion batteries are dangerous, they may explode if (a) overcharged or (b)
discharged too rapidly. That's why individual cells are almost unavailable.
Battery packs come with the necessary circuitry to protect the cells. As
long as you use an existing pack I wouldn't be too concerned. Please note
that contrary to NiCd, Li-Ion cells cannot deliver high peak currents. The
expert at www.buchmann.ca indicates a peak load of 2C for Li-Ion vs 20C for
NiCd.
I successfully salvaged individual Li-Ion cells from defeective notebook
battery packs and used them to build an external power source for my
digicam. Since I continue to use the original protection circuit I'm feeling
safe doing so.
Remember to have seen an article recently in a German ham radio magazine
describing the use of salvaged Li-Ion cells to power a transceiver. But also
there the original protection circuit was used.

Markus HB9BRJ / AE6MG

On Tue, 6 Jan 2004, Markus L wrote:

Thank you for the pointer to the on-line book! I had a good read.

Li-Ion batteries are dangerous, they may explode if (a) overcharged or (b)
discharged too rapidly. That's why individual cells are almost unavailable.
Battery packs come with the necessary circuitry to protect the cells. As
long as you use an existing pack I wouldn't be too concerned. Please note
that contrary to NiCd, Li-Ion cells cannot deliver high peak currents. The
expert at www.buchmann.ca indicates a peak load of 2C for Li-Ion vs 20C for
NiCd.

In this case I'm considering using the laptop battery itself, not opening
it up and extracting the cells. Overcharging shouldn't be a problem,
because I'd be using the laptop itself to recharge the battery. I don't
think that I'll be drawing too much current, either, as the DSW-40 (an
original one) only puts out about 2 watts.

BUT, with the warnings about Li-Ion cells in mind I think I'll see if I
can learn more about the battery packs made for my particular laptop to
determine if I really want to do this.

Thanks!

-Josh, AE6IQ

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Remove the reversed "nospam" in the address.

In this case I'm considering using the laptop battery itself, not opening
it up and extracting the cells. Overcharging shouldn't be a problem,
because I'd be using the laptop itself to recharge the battery. I don't
think that I'll be drawing too much current, either, as the DSW-40 (an
original one) only puts out about 2 watts.

BUT, with the warnings about Li-Ion cells in mind I think I'll see if I
can learn more about the battery packs made for my particular laptop to
determine if I really want to do this.


At 2 watts, your DSW-40 current requirment is pretty low....way below the
battery's A/H rating. WAY BELOW. I=P/E = 2/12 = 160ma.

If you are that worried about using the laptop battery, get a 12v lantern
battery. It will last for months of QSO's. I used one with an HW-8 and it
was FB for about 3 or 4 months. It lasted so long, I thought it would never
run down. With your DSW-40, it might lose more energy through shelf-life
than operating time. :-)

Either way you go, go for it.

73
dale, kg5u

In this case I'm considering using the laptop battery itself, not opening
it up and extracting the cells. Overcharging shouldn't be a problem,
because I'd be using the laptop itself to recharge the battery. I don't
think that I'll be drawing too much current, either, as the DSW-40 (an
original one) only puts out about 2 watts.

BUT, with the warnings about Li-Ion cells in mind I think I'll see if I
can learn more about the battery packs made for my particular laptop to
determine if I really want to do this.


At 2 watts, your DSW-40 current requirment is pretty low....way below the
battery's A/H rating. WAY BELOW. I=P/E = 2/12 = 160ma.

If you are that worried about using the laptop battery, get a 12v lantern
battery. It will last for months of QSO's. I used one with an HW-8 and it
was FB for about 3 or 4 months. It lasted so long, I thought it would never
run down. With your DSW-40, it might lose more energy through shelf-life
than operating time. :-)

Either way you go, go for it.

73
dale, kg5u

On Tue, 6 Jan 2004, Markus L wrote:

Thank you for the pointer to the on-line book! I had a good read.

Li-Ion batteries are dangerous, they may explode if (a) overcharged or (b)
discharged too rapidly. That's why individual cells are almost unavailable.
Battery packs come with the necessary circuitry to protect the cells. As
long as you use an existing pack I wouldn't be too concerned. Please note
that contrary to NiCd, Li-Ion cells cannot deliver high peak currents. The
expert at www.buchmann.ca indicates a peak load of 2C for Li-Ion vs 20C for
NiCd.

In this case I'm considering using the laptop battery itself, not opening
it up and extracting the cells. Overcharging shouldn't be a problem,
because I'd be using the laptop itself to recharge the battery. I don't
think that I'll be drawing too much current, either, as the DSW-40 (an
original one) only puts out about 2 watts.

BUT, with the warnings about Li-Ion cells in mind I think I'll see if I
can learn more about the battery packs made for my particular laptop to
determine if I really want to do this.

Thanks!

-Josh, AE6IQ

--


Remove the reversed "nospam" in the address.