Voltage Multiplier ?

[Gaz]

G'day to the group.

I'm trying to work out how to run my laptop from my car battery.

Here's the problem : The laptop needs 19V DC at about 4A.

Of course the car battery is only 12V so I need something to step up
the voltage, and it also needs to deliver a pretty hefty current.

I remember a while ago dealing with a voltage multiplier which could
double, quadruple etc a DC potential difference.

Does anybody know where to look for a circuit, and am I on the right
track with a voltage multiplier? Or is the requirement of 4A too much?

I guess I could also use a step-up transformer but the process of
converting to AC, then step-up, then rectifying to DC, then regulating
to 19V sounds a bit complicated.

Thanks.

Gaz

 

[Phil Allison]

"Gaz" <gaz@gaz.com>

I'm trying to work out how to run my laptop from my car battery.

** Go buy an adaptor for intended the purpose.

If you can afford a laptop you can afford the car adaptor.

Here's the problem : The laptop needs 19V DC at about 4A.
Of course the car battery is only 12V so I need something to step up
the voltage, and it also needs to deliver a pretty hefty current.
I remember a while ago dealing with a voltage multiplier which could
double, quadruple etc a DC potential difference.

** Voltage multipliers require an AC input.

Does anybody know where to look for a circuit, and am I on the right
track with a voltage multiplier?

** You could always get another car battery to double the voltage.

I guess I could also use a step-up transformer but the process of
converting to AC, then step-up, then rectifying to DC, then regulating
to 19V sounds a bit complicated.

** Electronics was never meant to be easy .........




.......... Phil

 

[Gaz]

Phil, you are right. I should just buy the adaptor, and I seriously
did think about just wiring an extra battery in series, then stepping
down the ruslting 24V.

I know I've seen some circuits that require an ac input but somewhere
I recall seeing one that used DC also.....Damn brain ! Perhaps it had
a sine-wave generator in the circuit - I'm not sure.

And yes, I should not ask for everything to be easy. In fact I do have
an easy solution to the problem (below) and I thought I'd try the
less-than-easy path and see if I could build something myself.

In fact my laptop is a very obscure brand (EXCEL) and I can't find an
adaptor specifically for it. I think I can just just buy a 12-to-240V
invertor and then use the laptop's mains adaptor into this.



On Tue, 25 May 2004 21:54:52 +1000, "Phil Allison"
<philallison@tpg.com.au> wrote:

"Gaz" <gaz@gaz.com


I'm trying to work out how to run my laptop from my car battery.


** Go buy an adaptor for intended the purpose.

If you can afford a laptop you can afford the car adaptor.



Here's the problem : The laptop needs 19V DC at about 4A.
Of course the car battery is only 12V so I need something to step up
the voltage, and it also needs to deliver a pretty hefty current.
I remember a while ago dealing with a voltage multiplier which could
double, quadruple etc a DC potential difference.



** Voltage multipliers require an AC input.


Does anybody know where to look for a circuit, and am I on the right
track with a voltage multiplier?


** You could always get another car battery to double the voltage.


I guess I could also use a step-up transformer but the process of
converting to AC, then step-up, then rectifying to DC, then regulating
to 19V sounds a bit complicated.


** Electronics was never meant to be easy .........




......... Phil

 

[Phil Allison]

"Gaz" <gaz@gaz.com>

Phil, you are right. I should just buy the adaptor, and I seriously
did think about just wiring an extra battery in series, then stepping
down the ruslting 24V.

** It was a joke - Joyce.

In fact my laptop is a very obscure brand (EXCEL) and I can't find an
adaptor specifically for it.

** Any 12 volt to 19 volt at 4 amp adaptor will do the job - you just
need to get the DC connector to the laptop right.

I think I can just just buy a 12-to-240V
invertor and then use the laptop's mains adaptor into this.

** That is the **wimp's** way out .....




........... Phil

 

[Kevin]

"Gaz" <gaz@gaz.com> wrote in message
news:c5c6b01vhomv03suao3r9ntglh9f140imh@4ax.com...

G'day to the group.

I'm trying to work out how to run my laptop from my car battery.

Here's the problem : The laptop needs 19V DC at about 4A.

Of course the car battery is only 12V so I need something to step up
the voltage, and it also needs to deliver a pretty hefty current.

real cars have dual battery.

I remember a while ago dealing with a voltage multiplier which could
double, quadruple etc a DC potential difference.

Does anybody know where to look for a circuit, and am I on the right
track with a voltage multiplier? Or is the requirement of 4A too much?

I guess I could also use a step-up transformer but the process of
converting to AC, then step-up, then rectifying to DC, then regulating
to 19V sounds a bit complicated.

Thanks.

Gaz

 

[Craig Hart]

** Any 12 volt to 19 volt at 4 amp adaptor will do the job - you just
need to get the DC connector to the laptop right.

Targus sell that sort of thing -
http://www.targus.com/au/accessories_power.asp

The voltage isn't terribly critical - a straight 12v from the car (which
will be more like 13.8v anyhow) will do, once filtered and (sort-of)
regulated by one of these things.

 

[Rod Speed]

Just buy one intended for that, powering laptops from cars.

Plenty on ebay and the yank ones are very good value.


"Gaz" <gaz@gaz.com> wrote in message news:c5c6b01vhomv03suao3r9ntglh9f140imh@4ax.com...

G'day to the group.

I'm trying to work out how to run my laptop from my car battery.

Here's the problem : The laptop needs 19V DC at about 4A.

Of course the car battery is only 12V so I need something to step up
the voltage, and it also needs to deliver a pretty hefty current.

I remember a while ago dealing with a voltage multiplier which could
double, quadruple etc a DC potential difference.

Does anybody know where to look for a circuit, and am I on the right
track with a voltage multiplier? Or is the requirement of 4A too much?

I guess I could also use a step-up transformer but the process of
converting to AC, then step-up, then rectifying to DC, then regulating
to 19V sounds a bit complicated.

Thanks.

Gaz