Capacitor back-up??

1/16/2010 2:08:27 PMElton

Hi all I drive truck and as all truckers do , I built a radio box to house the C.B. and stereo radio, this truck the power is switched by the key so to keep the memory on the radio, I use a 9 volt battery. It works OK but the down side is I have to replace the battery every few months. Is there a circuit that could use a capacitor to replace the battery in this case? and save me batteries?
Thanks
Elton

1/16/2010 3:15:41 PMWarren

From the key power switch, (hot side) add a inline fuse and wire to your radios. No need for any 9 volt back up then.

1/16/2010 8:33:00 PMDave A.

Warren's suggestion below is the best, most widely accepted solution - Common for car radios. Does not take much to hold memory only. Is there a reason not to do this?

If it is going to power more than that, you may want a switch in series (with the fuse) to be able to switch off in case of extended down time or low battery.

Dave

:From the key power switch, (hot side) add a inline fuse and wire to your radios. No need for any 9 volt back up then.

1/16/2010 8:44:26 PMSteve in Missouri

:From the key power switch, (hot side) add a inline fuse and wire to your radios. No need for any 9 volt back up then.
:
The way I read the post, he has the CB and the stereo in a box so he can remove them from the truck. He may drive a different truck each day and not be able to hard wire them to an unswitched source.
Steve

1/16/2010 10:53:28 PMElton

::From the key power switch, (hot side) add a inline fuse and wire to your radios. No need for any 9 volt back up then.
::
: The way I read the post, he has the CB and the stereo in a box so he can remove them from the truck. He may drive a different truck each day and not be able to hard wire them to an unswitched source.
: Steve

Hi Steve, you are correct we can't hard wire to any of the trucks , I guess they have had too many computer failures due to bad wiring hooh ups.
Elton
:

1/16/2010 11:32:05 PMWarren

Oh .. Okay then. I that case how about a NiCad 9 volt battery. Wire in a simple NiCad charger in with your radios in the box. (trickle charge) This way the battery is always getting charged while you drive.

1/16/2010 11:40:42 PMThomas Dermody

Cigarette lighter sockets are, often enough, always on. Some of the newer cars have them on the switched side, but traditionally they are wired before the switch. Purchase a cigarette lighter accessory cord and use this to power your CB.

1/16/2010 11:46:25 PMThomas Dermody

Though, actually, Warren's idea should be good enough. Connect the NiCad to the radio's power wiring through a resistor to adequately limit charging current (I don't know what it should be). Parallel the resistor with a diode that is wired so that the 9 volt can discharge into the radio at full power, but full power cannot be applied to the 9 volt. Also place a diode in the radio's power wiring prior to both the radio and the battery so that power can go to the radio and the battery, but the battery's power cannot go back into the wiring of the truck, or else when you turn the ignition switch off, the 9 volt will be powering everything that was fed by the ignition switch.

1/16/2010 3:18:31 PMJay W.

:Hi all I drive truck and as all truckers do , I built a radio box to house the C.B. and stereo radio, this truck the power is switched by the key so to keep the memory on the radio, I use a 9 volt battery. It works OK but the down side is I have to replace the battery every few months. Is there a circuit that could use a capacitor to replace the battery in this case? and save me batteries?
:Thanks
:Elton
:

You will need a pretty huge value capacitor to replace the 9V battery.You can find memory ackup capacitors on the market for a few dollars (1F) but they are only 5V. There might be some available at higher voltages.

Look at websites such as electronics goldmine and similar surplus websites. Search for at least 1F capacitors (that is 1 Farad, not microFarad!)

1/16/2010 5:31:39 PMLewis L

::Hi all I drive truck and as all truckers do , I built a radio box to house the C.B. and stereo radio, this truck the power is switched by the key so to keep the memory on the radio, I use a 9 volt battery. It works OK but the down side is I have to replace the battery every few months. Is there a circuit that could use a capacitor to replace the battery in this case? and save me batteries?
::Thanks
::Elton

Something else to think about is to use a rechargable 9 Volt battery. BG Micro has one at a very good price, I have a charger and change the depleated battery with a fresh one as required.
Lewis
::
:
:You will need a pretty huge value capacitor to replace the 9V battery.You can find memory ackup capacitors on the market for a few dollars (1F) but they are only 5V. There might be some available at higher voltages.
:
:Look at websites such as electronics goldmine and similar surplus websites. Search for at least 1F capacitors (that is 1 Farad, not microFarad!)
:

1/20/2010 2:10:16 AMPenlite Cells or Larger

It seems a little odd that the batteries only last a few months. It should take almost nothing (uamps) to keep the memory up. How is the battery connected? Have you measured the current drain? Are you sure the battery is only holding up the memory?

If you have room, a holder with 6 penlite (AA) cells wired in series will make up a 9 volt battery that will last at least five times longer than a single 9 volt. Larger cells will last even longer.

:::Hi all I drive truck and as all truckers do , I built a radio box to house the C.B. and stereo radio, this truck the power is switched by the key so to keep the memory on the radio, I use a 9 volt battery. It works OK but the down side is I have to replace the battery every few months. Is there a circuit that could use a capacitor to replace the battery in this case? and save me batteries?
:::Thanks
:::Elton
:
:

1/23/2010 1:53:57 PMElton

I had a buddy who has done this with his radio check my set up out , It appears that their is something wrong with my particular radio , the way it is wired ... it seems the memory wire also needs to be hooked to the main switched power to operate, if you just hook it to a seperate battery it will not operate , but if you connect it also to the main red wire it will work??? guess I need to buy a good radio instead of buying the cheap crap from wally world...
E.
:It seems a little odd that the batteries only last a few months. It should take almost nothing (uamps) to keep the memory up. How is the battery connected? Have you measured the current drain? Are you sure the battery is only holding up the memory?
:
:If you have room, a holder with 6 penlite (AA) cells wired in series will make up a 9 volt battery that will last at least five times longer than a single 9 volt. Larger cells will last even longer.
:
:
:
::::Hi all I drive truck and as all truckers do , I built a radio box to house the C.B. and stereo radio, this truck the power is switched by the key so to keep the memory on the radio, I use a 9 volt battery. It works OK but the down side is I have to replace the battery every few months. Is there a circuit that could use a capacitor to replace the battery in this case? and save me batteries?
::::Thanks
::::Elton
::
::
:
:

1/23/2010 5:07:55 PMEdd

Sir Elton. . . . . (John?)

Methinks that if you have that radio hook up as per diagram # 1, that you are getting some additional current
consumption on that battery that you are showing used as memory retention.

Look via the Fuscia path and one sees the YELLOW resistor indicating potential phantom leakage thru the radio proper.

If the hook up was changed, as per # 2, the backward leakage path would be blocked by the aditional use of an isolation / steering
diode as is shown by its FUSCIA path .

Could be as simple as a common switching diode 1N914 / 4148 or as commonly found as a power diode
1N4001---4007.

Plus . . . no extra charge . . . when being used in ye olde trucke . . .there is a very mild trickle charge being provided for the add on memory storage battery via the 330 ohm 1/2 watt .

Your 9V alkaline should then almost be shelf life, with that systems CMOS’s , femto - - - micro ampere memory retention requirements drain.

73's de Edd

1/23/2010 9:26:57 PMElton

:Edd,
Thanks for your info I was considering using some sort of diode to block the leakage did'nt think of the resistor thou... I will try it and see how it works
Thanks
E.
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:Sir Elton. . . . . (John?)
:
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:Methinks that if you have that radio hook up as per diagram # 1, that you are getting some additional current
:consumption on that battery that you are showing used as memory retention.
:
:
:Look via the Fuscia path and one sees the YELLOW resistor indicating potential phantom leakage thru the radio proper.
:
:
:
:
:If the hook up was changed, as per # 2, the backward leakage path would be blocked by the aditional use of an isolation / steering
:diode as is shown by its FUSCIA path .
:
:
:Could be as simple as a common switching diode 1N914 / 4148 or as commonly found as a power diode
:1N4001---4007.
:
:
:
:Plus . . . no extra charge . . . when being used in ye olde trucke . . .there is a very mild trickle charge being provided for the add on memory storage battery via the 330 ohm 1/2 watt .
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:Your 9V alkaline should then almost be shelf life, with that systems CMOS’s , femto - - - micro ampere memory retention requirements drain.
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:73's de Edd
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