question about Sirius radio car docking kit power supply

[Dave]

Folks;

Silly electronics question ....

I have the JVC KT-SR1000 Sirius radio tuner, and the JVC KS-K6002 car
docking kit. It uses a 12V DC cigarette lighter power cord. I'd like
to use this docking kit in my home, as well, off of AC power. Can I
use any ol' AC to 12V DC converter? All I know is that the existing
cigarette lighter power cord contains a 3 amp fuse, and that the
manual which came with the docking kit says to make sure that the
power supply has a negative ground.

Thanks in advance.

[Mark Hansen]

On 7/15/2004 10:33, Dave wrote:

> Folks;
>
> Silly electronics question ....
>
> I have the JVC KT-SR1000 Sirius radio tuner, and the JVC KS-K6002 car
> docking kit. It uses a 12V DC cigarette lighter power cord. I'd like
> to use this docking kit in my home, as well, off of AC power. Can I
> use any ol' AC to 12V DC converter? All I know is that the existing
> cigarette lighter power cord contains a 3 amp fuse, and that the
> manual which came with the docking kit says to make sure that the
> power supply has a negative ground.

In the U.S., negative ground is pretty common, so you should not have
to worry about that (assuming you're in the U.S.). 12 volts is 12 volts.
However, you need to make sure that the power supply can support the
current requirements of the device. It should state this in its spec
sheet.

For example, if it draws 800ma (milliamps), then your power supply needs
to be able to support that much or you'll burn it up.

Note also that the device may be designed for use on a battery supply,
and may not tolerate the noise that can be found with some wall wart
power supplies.


>
> Thanks in advance.

[Bruce Chang]

"Mark Hansen" > wrote in message
...
> On 7/15/2004 10:33, Dave wrote:
>
> > Folks;
> >
> > Silly electronics question ....
> >
> > I have the JVC KT-SR1000 Sirius radio tuner, and the JVC KS-K6002 car
> > docking kit. It uses a 12V DC cigarette lighter power cord. I'd like
> > to use this docking kit in my home, as well, off of AC power. Can I
> > use any ol' AC to 12V DC converter? All I know is that the existing
> > cigarette lighter power cord contains a 3 amp fuse, and that the
> > manual which came with the docking kit says to make sure that the
> > power supply has a negative ground.
>
> In the U.S., negative ground is pretty common, so you should not have
> to worry about that (assuming you're in the U.S.). 12 volts is 12 volts.
> However, you need to make sure that the power supply can support the
> current requirements of the device. It should state this in its spec
> sheet.
>
> For example, if it draws 800ma (milliamps), then your power supply needs
> to be able to support that much or you'll burn it up.
>
> Note also that the device may be designed for use on a battery supply,
> and may not tolerate the noise that can be found with some wall wart
> power supplies.
>

You'll need to be careful if the power supply you're using is unregulated
power. It may say "12V" but that is the voltage at the rated load, at no
load it could be 18+ volts. Typically I haven't had any problems using
unregulated power supplies but that doesn't mean that no one will ever have
any problems. The only other thing is to watch out for the polarity. Some
companies like to switch polarities around, apparently to **** me off..

-Bruce

[Dave Platt]

In article >,
Bruce Chang > wrote:

>You'll need to be careful if the power supply you're using is unregulated
>power. It may say "12V" but that is the voltage at the rated load, at no
>load it could be 18+ volts. Typically I haven't had any problems using
>unregulated power supplies but that doesn't mean that no one will ever have
>any problems.

That's good advice. Fortunately (for the original poster), electronic
devices which are designed to plug into a vehicle's cigarette lighter
outlet are almost certainly designed to survive moderate overvoltage
with good grace.

The reasons are twofold. First, an automobile's "12-volt" voltage is
poorly regulated at best. It's often down around 12-point-something
volts when the engine is off, is usually considered to have a nominal
rating of 13.6 - 13.8 volts, and often rises up to 14.5 - 15 volts
when the alternator is working hard to recharge the battery after a
start.

The second is that an automobile's "12-volt" voltage is often _very_
noisy. There's a phenomenon known as "load dump" which occurs when
you shut off an electrical load (e.g. turn off the headlights) when
the alternator is powering the load. An inductive "kickback" occurs
when this happens, and it generates a short-duration high-voltage
spike on the car's power wiring.

My recollection is that load dumps can easily generate a spike of up
to 50 volts. Any lighter-outlet-powered device which can't survive
this would probably have a rather short lifetme in automobile service.

I agree, though - pick yourself a good, well-regulated 12-volt or
13.8-volt power supply, and your Sirius should be quite happy with it.

--
Dave Platt > AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

[Dave]

Mark Hansen > wrote in message >...
> On 7/15/2004 10:33, Dave wrote:
>
> > Folks;
> >
> > Silly electronics question ....
> >
> > I have the JVC KT-SR1000 Sirius radio tuner, and the JVC KS-K6002 car
> > docking kit. It uses a 12V DC cigarette lighter power cord. I'd like
> > to use this docking kit in my home, as well, off of AC power. Can I
> > use any ol' AC to 12V DC converter? All I know is that the existing
> > cigarette lighter power cord contains a 3 amp fuse, and that the
> > manual which came with the docking kit says to make sure that the
> > power supply has a negative ground.
>
> In the U.S., negative ground is pretty common, so you should not have
> to worry about that (assuming you're in the U.S.). 12 volts is 12 volts.
> However, you need to make sure that the power supply can support the
> current requirements of the device. It should state this in its spec
> sheet.

Unfortunately I can't find the spec sheet, and JVC tech support won't
tell me, they just keep saying "you need to buy the home docking kit"
(of course).

[Larry]

You may want to try a DC to AC convertor, one that plugs into a 120v
outlet and gives you a cigarette lighter receptacle. I use it to
recharge my PDA and cell phones. I'm not sure how many amps the radio
draws but the output is rated at 0.5A.

http://www.igo.com/Product_Detail.asp?PageSource=&CategoryID=&ItemID=4519&ModelGroupID=&BrandID=&ModelID=

(Dave) wrote in message >...
> Mark Hansen > wrote in message >...
> > On 7/15/2004 10:33, Dave wrote:
> >
> > > Folks;
> > >
> > > Silly electronics question ....
> > >
> > > I have the JVC KT-SR1000 Sirius radio tuner, and the JVC KS-K6002 car
> > > docking kit. It uses a 12V DC cigarette lighter power cord. I'd like
> > > to use this docking kit in my home, as well, off of AC power. Can I
> > > use any ol' AC to 12V DC converter? All I know is that the existing
> > > cigarette lighter power cord contains a 3 amp fuse, and that the
> > > manual which came with the docking kit says to make sure that the
> > > power supply has a negative ground.
> >
> > In the U.S., negative ground is pretty common, so you should not have
> > to worry about that (assuming you're in the U.S.). 12 volts is 12 volts.
> > However, you need to make sure that the power supply can support the
> > current requirements of the device. It should state this in its spec
> > sheet.
>
> Unfortunately I can't find the spec sheet, and JVC tech support won't
> tell me, they just keep saying "you need to buy the home docking kit"
> (of course).