# Charging laptop battery from car 12V

V

#### Vidor Wolf

Jan 1, 1970
0
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.

G

#### Garrett Mace

Jan 1, 1970
0
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. V #### Vidor Wolf Jan 1, 1970 0 Garrett Mace said: 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.

V

#### Vidor Wolf

Jan 1, 1970
0
Garrett Mace said:
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.

Replies
7
Views
2K
T
Replies
10
Views
5K
Clint Sharp
C
M
Replies
13
Views
20K