12V DC mobile power supply (battery pack)
Andrew Kesterson
I want to take a mobile CB radio, designed to run off of a 12 volt
power line in an automotive vehicle, and convert it to run on 9V, C, or D
cell batteries so I can put it in a backpack and take it with me when I go
on long hikes away from home and the like, and talk back to a base station
in the house.
Would it be as simple as connecting a bunch of batteries together in
circuit and using a resistor (or series of resistors) to lower the current
(if too high), or using an amplifier to raise it?
I have some basic electronics books on these subjects (basic, basic
digital, and basic communications electronics books from radio shack), but
I wanted to get some input before I went and tried to do something and
blew up my radio. :-)
Would this be possible using the methods I described? Would I need other
methods? Or would I just need to give it up and try something else?
(Also, does anyone know where I might find information about changing the
frequencies the radio runs on? If I could find a way to make it run on the
same frequencies as some smaller GMRS radios I have, that'd be awesome...
but from what I understand it would probably require changing the entire
guts of the radio... so if that's not feasible don't worry too much about
it. :-)
Thanks alot in advance
js_530
> I have been looking on google and can't find anything on this subject.
>
> I want to take a mobile CB radio, designed to run off of a 12 volt
> power line in an automotive vehicle, and convert it to run on 9V, C, or D
> cell batteries so I can put it in a backpack and take it with me when I go
> on long hikes away from home and the like, and talk back to a base station
> in the house.
>
> Would it be as simple as connecting a bunch of batteries together in
> circuit and using a resistor (or series of resistors) to lower the current
> (if too high), or using an amplifier to raise it?
You could not get a voltage higher than what you have from the
batteries, so the amplifier cannot be used. You need 12 volts or
higher from the batteries, because there's probally a good reason the
radio runs on 12 volts. If you had a voltage higher than 12 volts,
you could use a 12 volt regulator, but not resistors. The radio is
non-linear, and changes resistance based on whether or not it's being
used, so a regulator is needed. You might want to see how much
current the radio draws, and buy a 12 volt regulator higher than your
maximum current rating. If you are using a source slightly higher
than 12 volts, than you need a minimum voltage dropoff rating on the
regulator of the difference between the battery voltage and 12 volts.
> I have some basic electronics books on these subjects (basic, basic
> digital, and basic communications electronics books from radio shack), but
> I wanted to get some input before I went and tried to do something and
> blew up my radio. :-)
>
> Would this be possible using the methods I described? Would I need other
> methods? Or would I just need to give it up and try something else?
>
> (Also, does anyone know where I might find information about changing the
> frequencies the radio runs on? If I could find a way to make it run on the
> same frequencies as some smaller GMRS radios I have, that'd be awesome...
> but from what I understand it would probably require changing the entire
> guts of the radio... so if that's not feasible don't worry too much about
> it. :-)
I believe this is possible, and inexpensive, but I'm not sure how you
would do this. You would have to desolder either a crystal or a
capacitor, then solder on another one. Both componants are under a
dollar.
> Thanks alot in advance
Seth Koster
>
> I want to take a mobile CB radio, designed to run off of a 12 volt
> power line in an automotive vehicle, and convert it to run on 9V, C, or D
> cell batteries so I can put it in a backpack and take it with me when I go
> on long hikes away from home and the like, and talk back to a base station
> in the house.
>
> Would it be as simple as connecting a bunch of batteries together in
> circuit and using a resistor (or series of resistors) to lower the current
> (if too high), or using an amplifier to raise it?
>
8 1.5V batteries will give you 12V (C or D), the circuit will draw
the amperage it needs (probably more than you want, considering
battery life). You might consider buying one of those handy talky
type radios which are designed to run on batteries.
> I have some basic electronics books on these subjects (basic, basic
> digital, and basic communications electronics books from radio shack), but
> I wanted to get some input before I went and tried to do something and
> blew up my radio. :-)
>
> Would this be possible using the methods I described? Would I need other
> methods? Or would I just need to give it up and try something else?
>
> (Also, does anyone know where I might find information about changing the
> frequencies the radio runs on? If I could find a way to make it run on the
> same frequencies as some smaller GMRS radios I have, that'd be awesome...
> but from what I understand it would probably require changing the entire
> guts of the radio... so if that's not feasible don't worry too much about
> it. :-)
>
Sure its possible, its also illegal and harder than just getting a
ham radio license and then getting a lot more range by applying good
antenna designs to a good ham band radio.