Electronics Question

[John Shepardson]

I have a portable 12 volt power station (jump starter) that I want to
use as a camping trip power supply. I took it apart and found that it
has a 20 amp hour battery and a charger (actually a wall wart stuffed
inside) rated at 0.5 amps at 12 volts.

The problem is it takes 2 days to charge the battery up, and I want it
to fully charge in 8 hours on the road.

So I need a charger rated at 3 amps & 12 volts (or 14 volts, my car¹s
normal setting is fine) to charge this battery in one day of driving.
It can¹t be much more than 3 amps, because it has to plug into my cigar
lighter in the interior (5A fuse). It can¹t be much less because it
won¹t charge in one day.

I guess what I need is to restrict the maximum amps that flow into the
power station. How do I do this?

Thanks for any help,
John

[Matt Ion]

John Shepardson wrote:
> I have a portable 12 volt power station (jump starter) that I want to
> use as a camping trip power supply. I took it apart and found that it
> has a 20 amp hour battery and a charger (actually a wall wart stuffed
> inside) rated at 0.5 amps at 12 volts.
>
> The problem is it takes 2 days to charge the battery up, and I want it
> to fully charge in 8 hours on the road.
>
> So I need a charger rated at 3 amps & 12 volts (or 14 volts, my car¹s
> normal setting is fine) to charge this battery in one day of driving.
> It can¹t be much more than 3 amps, because it has to plug into my cigar
> lighter in the interior (5A fuse). It can¹t be much less because it
> won¹t charge in one day.
>
> I guess what I need is to restrict the maximum amps that flow into the
> power station. How do I do this?

A resistor is the easiest way, although you'd need one with a pretty
hefty power rating. A better option would be a constant-current power
supply, but that's expensive.

The other consideration is whether the battery will survive that high a
charge rate.

Best solution is to plug it in at home two days before you leave.


---
avast! Antivirus: Outbound message clean.
Virus Database (VPS): 0613-2, 03/31/2006
Tested on: 4/1/2006 11:25:26 AM
avast! - copyright (c) 1988-2005 ALWIL Software.
http://www.avast.com

[Tony F]

Hey John. I apologize for rudely cutting in on your discussion (truth is I
have NO idea how to answer your question about the battery). But I was
wondering how you got the number "1" to appear instead of apostophes in your
text? It just struck me as weird, that's all.

For example, "It can¹t be much less because it won¹t charge in one day."

Tony


--
2001 Nissan Maxima SE Anniversary Edition
Clarion DRZ9255 Head Unit, Phoenix Gold ZX475ti, ZX450 and Xenon X1200.1
Amplifiers, Dynaudio System 360 Tri-Amped In Front and Focal 130HCs For Rear
Fill, Image Dynamics IDMAX10 D4 v.3 Sub

2001 Chevy S10 ZR2
Pioneer DEH-P9600MP Head Unit, Phoenix Gold Ti500.4 Amp, Focal 165HC
Speakers & Image Dynamics ID8 D4 v.3 Sub

2006 Mustang GT Coupe

[MOSFET]

> Hey John. I apologize for rudely cutting in on your discussion (truth is
> I
> have NO idea how to answer your question about the battery). But I was
> wondering how you got the number "1" to appear instead of apostophes in
> your text? It just struck me as weird, that's all.
>
> For example, "It can¹t be much less because it won¹t charge in one day."

Whoa, that's NOT how that looked to me. That's REALLY WEIRD. Time to join
the world, Tony, and switch to MS OE.

Nick

[MOSFET]

Duh. Sorry Tony. Yes, that IS how it looked to me. :)

Nick

[Austin Becker]

I was wondering when you were going to realize. :)

--
- AUSTIN BECKER
"MOSFET" > wrote in message
m...
> Duh. Sorry Tony. Yes, that IS how it looked to me. :)
>
> Nick
>
>