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Is there a 12VDC power regulator / timer?

Mark2536

Oct 25, 2019
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Oct 25, 2019
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The scene: a vehicle sits idle (not driven at all) for up to two weeks.
When parked, there IS some IOD (Ignition Off Draw) that slowly drains the battery.
That IOD draw is not enough to drain the battery to where the car will not start.
However, IN the vehicle is also a cell phone that is used as an anti-theft device.
That's actually a fairly cool idea (me thinks), fully described at:
https://www.howardforums.com/showth...old-cell-phone-as-a-vehicle-GPS-tracker/page1
OK, it won't keep the car from being stolen, but it will Locate the stolen vehicle.
And a cell phone charger will drain the car battery if it is forever charging.
The problem: how to keep that cell phone charged, Without draining the car battery.
Is there a device that can be constantly hooked up to the 12VDC power,
and it can be set to Do Nothing (close to Zero power draw) for 22 hours of the day,
and for the other two hours daily it will allow power to go to the cell phone charger?
Hopefully, that will keep the cell phone alive without draining the battery too much.
Does it exist? Can it be easily built? Ideas?
Thanks, people.
Mark2536
 

AnalogKid

Jun 10, 2015
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Jun 10, 2015
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If by "device" you mean something you can purchase, I don't know of one. As a circuit it would be fairly simple. I like the CD4060 oscillator/divider as the basis for loooong timer circuits. It is at its most simple when the requirements are binary relationships, like one hour on in every 16 hours. Would that be enough to keep the phone topped off?

ak
 
Last edited:

bushtech

Sep 13, 2016
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How about an intelligent maintenance battery charger for the vehicle?. Can be left attached attached indefinitely as it just tops up the car battery as required.
 

Mark2536

Oct 25, 2019
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Oct 25, 2019
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AK, Wow. I just looked up a CD4060 and that stuff is all beyond my comprehension,
with Oscillators and Frequency generators and Ripple-carries and Crystals and other technical jargon.
I'm just a rookie here. o_O I'll study it in more depth, to see if I can create such a thing.
Can ya' point me toward some links that might show how to do that?

Bush, yes, there's already a maintenance charger on the car when it's in my garage,
but the scenario that I'm asking about is when the car is Gone / stolen.

Thanks.
 

dave9

Mar 5, 2017
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Mar 5, 2017
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That will not make much difference. You have to leave the cell phone running so it is always consuming the same amount of power either way.

That is the amount of power that has to be put back into it from the vehicle battery. If your charging circuit is always live but the phone is fully charged, it draws very little, practically no power being live, using very close to the same total amount of power as if you had only had it on and charging two hours a day.

You could do one of two things, or both.

1) Put a solar panel on/in the vehicle to charge the battery.

2) Add an additional battery, either a lead acid 12V in parallel with the vehicle battery so the vehicle charging system will recharge it, or provide your own charging circuit for a different chemistry or voltage battery that is isolated from the vehicle battery and that charging circuit runs when the engine is on (alternator is outputting).

Also keep in mind that using an old phone, means an old battery, so for long term use you will need to replace the battery every X # of months. Frankly I would consider not using its battery at all, instead only one conversion using a buck switcher to give the phone 3.7V so you are not suffering the additional losses of converting 12V down to 5V/USB, then converting to the battery charging rate, then the battery itself having loss charging (more goes in than comes out). I don't know how a phone would react to only power and ground hooked up instead of also having the additional battery protection board wire(s) hooked up.
 

Terry01

Jul 5, 2017
206
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Jul 5, 2017
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Buddy you can buy a proper GPS tracker for under £10 that wires right into your battery that is low drain. Check Ebay and the likes.
 
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