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Chas
Guest
Wed Jan 18, 2012 11:55 pm
I plan to use a ''boombox" in my vehicle because the existing sound device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
.. . . . .I am of an understanding that 1.5v batterys are acutally 1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8 of the
AA's and tap off 6.
any help would be greatly appreciated.. . . chas
William Sommerwerck
Guest
Wed Jan 18, 2012 11:55 pm
You don't want to use a resistor, because if you turn up the volume, the
change in current drawn as the sound gets louder and softer will "modulate"
the voltage.
You need a properly regulated supply to step the voltage down to 9V. I don't
know who makes one, especially of the capacity needed for a boombox.
hrhofmann@att.net
Guest
Thu Jan 19, 2012 1:08 am
On Jan 18, 4:55 pm, "Chas" <footboar...@bresnan.net> wrote:
Quote:
I plan to use a ''boombox" in my vehicle because the existing sound device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally 1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8 of the
AA's and tap off 6.
any help would be greatly appreciated.. . . chas
AA batteries (regular carbon or nickel metal hydride) are 1.4 to
1.5V, NICAD AA batteries are 1.2V. So you need to drop 14V to 9V.
14V because that is the actual voltage of a car system whenever the
engine is running,12V is the nominal battery voltage when the engine
is not running.
You need to determine the current drain of the device in order to
figure out what value of resistor you need to put in series with the
14V to drop it to 9V. You need to drop 5V, the value of the resistor
needed is R=V/I where V=9, I=current drain in amps.
whit3rd
Guest
Thu Jan 19, 2012 1:51 am
On Wednesday, January 18, 2012 2:55:09 PM UTC-8, Chas wrote:
Quote:
I plan to use a ''boombox" in my vehicle because the existing sound device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox?
Well, yes there are plugs that would be safe. They're commonly
used for cellphones and such, and they contain a fuse and suitable
stepdown power supply. First, you need the power ratings of
the boombox (probably 9V at 1A will suffice to fill a small car
with tunes), and of the lighter socket.
The car power may have spikes up to 50V, so the conversion does
offer some challenges. If the 'boom box' has AC power option,
an off-the-shelf inverter to make 120VAC will be the easiest option.
Charlie
Guest
Thu Jan 19, 2012 2:35 am
If memory serves me (and it doesn't always), at the specified specific
gravity of a lead/acid cell for automotive use is the nominal voltage is2.2
volts.
Thus a fully charged 6 cell battery is nominally 13.2 volts.
But, of course, in the automotive world the battery is only used for
starting unless the engine is off. When engine is running the voltage
available to the vehicle's electrical system is determined by the alternator
and its associated regulation system.
A decent voltmeter is a handy way to check your own particular situation.
Charlie
<hrhofmann_at_att.net> wrote in message
news:5881c6c9-8bf9-4bba-98aa-83239d776dd2_at_e8g2000yqd.googlegroups.com...
On Jan 18, 4:55 pm, "Chas" <footboar...@bresnan.net> wrote:
Quote:
I plan to use a ''boombox" in my vehicle because the existing sound device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally 1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8 of
the
AA's and tap off 6.
any help would be greatly appreciated.. . . chas
AA batteries (regular carbon or nickel metal hydride) are 1.4 to
1.5V, NICAD AA batteries are 1.2V. So you need to drop 14V to 9V.
14V because that is the actual voltage of a car system whenever the
engine is running,12V is the nominal battery voltage when the engine
is not running.
You need to determine the current drain of the device in order to
figure out what value of resistor you need to put in series with the
14V to drop it to 9V. You need to drop 5V, the value of the resistor
needed is R=V/I where V=9, I=current drain in amps.
Rheilly Phoull
Guest
Thu Jan 19, 2012 3:07 am
On 1/19/2012 6:55 AM, Chas wrote:
Quote:
I plan to use a ''boombox" in my vehicle because the existing sound device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally 1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8 of the
AA's and tap off 6.
any help would be greatly appreciated.. . . chas
Just search for "three terminal regulator" until you find a circuit for
the 9volt one. This is a very simple circuit and easy to build, I have
had such in use for years in my vehicles. You can build it in a small
diecast box which would be strong and act as a heat sink for the regulator.
Rheilly P
mike
Guest
Thu Jan 19, 2012 6:08 am
On 1/18/2012 2:55 PM, Chas wrote:
Quote:
I plan to use a ''boombox" in my vehicle because the existing sound device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally 1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8 of the
AA's and tap off 6.
Don't do that. It's wrong for a lot of reasons.
You need a regulator.
If you intend building something, make sure you understand this:
http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf
Safest thing is to buy a car adapter.
Quote:
any help would be greatly appreciated.. . . chas
Rheilly Phoull
Guest
Thu Jan 19, 2012 6:43 am
On 1/19/2012 1:08 PM, mike wrote:
Quote:
On 1/18/2012 2:55 PM, Chas wrote:
I plan to use a ''boombox" in my vehicle because the existing sound
device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally
1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys
and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8
of the
AA's and tap off 6.
Don't do that. It's wrong for a lot of reasons.
You need a regulator.
If you intend building something, make sure you understand this:
http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf
Safest thing is to buy a car adapter.
any help would be greatly appreciated.. . . chas
Umm, looking at the OP's message that might be a tad over the top for
his level ??
Sure there can be lots of transients but I reckon for domestic
applications it's not necessary to go beyond some stiff caps or a
resistor and zener or even a choke where the job is to step down ?
Rheilly P
spamtrap1888
Guest
Thu Jan 19, 2012 8:38 am
On Jan 18, 9:43 pm, Rheilly Phoull <rhei...@bigslong.com> wrote:
Quote:
On 1/19/2012 1:08 PM, mike wrote:
On 1/18/2012 2:55 PM, Chas wrote:
I plan to use a ''boombox" in my vehicle because the existing sound
device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug from
the 12v cig lighter to a power plug on the boombox? I imagine I will need
some sort of voltage reducer. Anyone got any ideas on how one could build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally
1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys
and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8
of the
AA's and tap off 6.
Don't do that. It's wrong for a lot of reasons.
You need a regulator.
If you intend building something, make sure you understand this:
http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf
Safest thing is to buy a car adapter.
any help would be greatly appreciated.. . . chas
Umm, looking at the OP's message that might be a tad over the top for
his level ??
Sure there can be lots of transients but I reckon for domestic
applications it's not necessary to go beyond some stiff caps or a
resistor and zener or even a choke where the job is to step down ?
Anything's better than trying to use a battery string as a voltage
regulator. The worst that could happen using your idea is that he
would have to buy a new boom box. Second worst is that he would have
to buy a new three-terminal regulator.
Chas
Guest
Thu Jan 19, 2012 10:24 am
"Charlie" <left_at_thestation.com> wrote in message
Quote:
If memory serves me (and it doesn't always), at the specified specific
gravity of a lead/acid cell for automotive use is the nominal voltage
is2.2 volts.
.....< snip
Thus a fully charged 6 cell battery is nominally 13.2 volts.
Charlie
Yes, that is what I always see about auto battery voltages....13+vdc.
Chas
Chas
Guest
Thu Jan 19, 2012 11:03 am
Would you please share your schematic for the voltage regulator?
I would be most appreciative. . . . .Also, thanks for the guidance.
chas. L7912CV-Negative
http://www.ebay.com/itm/
2-Pcs-3-Terminals-1-5A-12V-L7912CV-Negative-Voltage-Regulator-/280803733057?pt=LH_DefaultDomain_0&hash=item416134ee41
.. . . .I'm curious...my first email to your address bounced...is it valid or
is my system messed up?
****************************
"Rheilly Phoull" <rheilly_at_bigslong.com> wrote in message
news:ztGdnW0YCOwtMIrSnZ2dnUVZ_u2dnZ2d_at_westnet.com.au...
Quote:
On 1/19/2012 1:08 PM, mike wrote:
On 1/18/2012 2:55 PM, Chas wrote:
I plan to use a ''boombox" in my vehicle because the existing sound
device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug
from
the 12v cig lighter to a power plug on the boombox? I imagine I will
need
some sort of voltage reducer. Anyone got any ideas on how one could
build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally
1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys
and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8
of the
AA's and tap off 6.
Don't do that. It's wrong for a lot of reasons.
You need a regulator.
If you intend building something, make sure you understand this:
http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf
Safest thing is to buy a car adapter.
any help would be greatly appreciated.. . . chas
Umm, looking at the OP's message that might be a tad over the top for his
level ??
Sure there can be lots of transients but I reckon for domestic
applications it's not necessary to go beyond some stiff caps or a resistor
and zener or even a choke where the job is to step down ?
Rheilly P
William Sommerwerck
Guest
Thu Jan 19, 2012 11:20 am
Here's another possibility...
Buy an inverter that converts 12V DC to 120V AC. Then use an AC power supply
("wall wart") suitable for the boombox. It might even have its own built-in
AC adapter.
William Sommerwerck
Guest
Thu Jan 19, 2012 12:28 pm
I find that UseNet groups almost always suggest the most-complex and
most-difficult-to-implement solutions one can imagine.
There are three simple solutions...
1) Use rechargeable batteries. This won't be cheap, but the OP can operate
the boombox anywhere. This is an essentially fool-proof solution.
2) Find a 9V auto cord.
http://www.radioshack.com/product/index.jsp?productId=3812864
3) Buy an inverter and use the power supply that came with the boombox.
http://www.amazon.com/Wagan-EL2402-SmartAC-Power-Inverter/dp/B000YQT6RS/ref=sr_1_2?s=electronics&ie=UTF8&qid=1326975432&sr=1-2
William Sommerwerck
Guest
Thu Jan 19, 2012 12:31 pm
Quote:
Buy an inverter that converts 12V DC to 120V AC. Then use an
AC power supply ("wall wart") suitable for the boombox. It might
even have its own built-in AC adapter.
total waste of energy ...
WHY?
It requires no energy -- it's plug 'n play.
mike
Guest
Thu Jan 19, 2012 12:33 pm
On 1/19/2012 2:03 AM, Chas wrote:
Quote:
Would you please share your schematic for the voltage regulator?
I would be most appreciative. . . . .Also, thanks for the guidance.
chas. L7912CV-Negative
http://www.ebay.com/itm/
2-Pcs-3-Terminals-1-5A-12V-L7912CV-Negative-Voltage-Regulator-/280803733057?pt=LH_DefaultDomain_0&hash=item416134ee41
. . . .I'm curious...my first email to your address bounced...is it valid or
is my system messed up?
****************************
"Rheilly Phoull"<rheilly_at_bigslong.com> wrote in message
news:ztGdnW0YCOwtMIrSnZ2dnUVZ_u2dnZ2d_at_westnet.com.au...
On 1/19/2012 1:08 PM, mike wrote:
On 1/18/2012 2:55 PM, Chas wrote:
I plan to use a ''boombox" in my vehicle because the existing sound
device
is defective and next to impossible to remove.
My boombox uses 6 AA batteries...would it be safe to just run a plug
from
the 12v cig lighter to a power plug on the boombox? I imagine I will
need
some sort of voltage reducer. Anyone got any ideas on how one could
build
such a reducer. I am fearing such a device may induce noise.
. . . . .I am of an understanding that 1.5v batterys are acutally
1.2v. Is
this correct? If so, I could run the 12v car voltage to 10 AA batterys
and
then tap off six batterys....
Else, if the AA's are truly 1.5 volts then run the 12v car power to 8
of the
AA's and tap off 6.
Don't do that. It's wrong for a lot of reasons.
You need a regulator.
If you intend building something, make sure you understand this:
http://www.littelfuse.com/data/en/Application_Notes/an9312.pdf
Safest thing is to buy a car adapter.
any help would be greatly appreciated.. . . chas
Umm, looking at the OP's message that might be a tad over the top for his
level ??
Sure there can be lots of transients but I reckon for domestic
applications it's not necessary to go beyond some stiff caps or a resistor
and zener or even a choke where the job is to step down ?
Rheilly P
Targus and Igo make universal car chargers. Can be had for $5 or so
shipped on ebay.
The problem is that they require special tips to configure the voltage
and the cheap ones come without tips.
But if you can design a regulator, you can open 'em up and add the
required voltage setting resistor and put the right plug on the wire.
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