Charging laptop battery from car 12V

[Vidor Wolf]

I posted the request below to alt.electronics, but got no response and
seeing as this appears to be a more active group, can anyone give me an idea
if this is ok...?
Cheers.
Mark H.

Over the next 4 day Easter weekend, I'll be in a place with no electricity
except the car.
I have an iBook that uses a 24V 3A PSU/Charger.
Can I use the car cigarette lighter socket to charge the laptop battery?
(Not run the laptop)
I was going to use a 27Ohm 3 Watt resistor to limit the current (it's what's
in my bits box) and feed this into a regulator (LM317T) to give me 12V at
around 500mA.
For the use it would get, I don't want to have to buy a car adapter and just
want a quick fix to recharge the battery a few times.
Many thanks.
Mark H.

 

[Garrett Mace]

Over the next 4 day Easter weekend, I'll be in a place with no electricity
except the car.
I have an iBook that uses a 24V 3A PSU/Charger.
Can I use the car cigarette lighter socket to charge the laptop battery?
(Not run the laptop)
I was going to use a 27Ohm 3 Watt resistor to limit the current (it's
what's
in my bits box) and feed this into a regulator (LM317T) to give me 12V at
around 500mA.
For the use it would get, I don't want to have to buy a car adapter and
just
want a quick fix to recharge the battery a few times.
Many thanks.
Mark H.

Just get a cheap power inverter. Cost ya $30 or so. Since you'll be without
electricity, you can use it to charge up your electric shaver, your cell
phone, a small TV, or whatever in addition to the laptop. So you're
converting 12V into some higher voltage and frequency, then down to 60 Hz
120VAC, then to your laptop supply which converts 60Hz 120VAC into some
higher voltage and frequency and then back to 24V DC. It'll work.

 

[Vidor Wolf]

"Garrett Mace" <g.ryan@macetech.com> wrote in message
news:WVOcc.48320$z%1.23950@twister.rdc-kc.rr.com...

Over the next 4 day Easter weekend, I'll be in a place with no
electricity
except the car.
I have an iBook that uses a 24V 3A PSU/Charger.
Can I use the car cigarette lighter socket to charge the laptop battery?
(Not run the laptop)
I was going to use a 27Ohm 3 Watt resistor to limit the current (it's
what's
in my bits box) and feed this into a regulator (LM317T) to give me 12V
at
around 500mA.
For the use it would get, I don't want to have to buy a car adapter and
just
want a quick fix to recharge the battery a few times.
Many thanks.
Mark H.


Just get a cheap power inverter. Cost ya $30 or so. Since you'll be
without
electricity, you can use it to charge up your electric shaver, your cell
phone, a small TV, or whatever in addition to the laptop. So you're
converting 12V into some higher voltage and frequency, then down to 60 Hz
120VAC, then to your laptop supply which converts 60Hz 120VAC into some
higher voltage and frequency and then back to 24V DC. It'll work.


Cheers for that...

The only reason I wanted to build, is I have the parts and this is a one off
trip. It was a free get out to charge the battery.
I'm in the UK and we tend to get ripped off on inverters etc.
Appreciated all the same, Mark.

 

[Vidor Wolf]

"Garrett Mace" <g.ryan@macetech.com> wrote in message
news:WVOcc.48320$z%1.23950@twister.rdc-kc.rr.com...

Just get a cheap power inverter. Cost ya $30 or so. Since you'll be
without
electricity, you can use it to charge up your electric shaver, your cell
phone, a small TV, or whatever in addition to the laptop. So you're
converting 12V into some higher voltage and frequency, then down to 60 Hz
120VAC, then to your laptop supply which converts 60Hz 120VAC into some
higher voltage and frequency and then back to 24V DC. It'll work.


OK, I've taken the advice on board and have bought a 150W inverter for 30

pounds from Maplins (Not my ideal choice of vendor, but they're local.)
Cheers.
Mark H.