Re: Bad Idea: Put 9V Flasher LED on top of 9V Battery??

From: Robert C Monsen (rcsurname_at_comcast.net)
Date: 06/19/04 

Date: Sat, 19 Jun 2004 06:56:56 GMT

"NoMailPlease" <DoNotSendMe@AnyMail.OK> wrote in message
news:KkNAc.769095$Pk3.59693@pd7tw1no...
> That sounds alot safer. I tried using 2 AA batteries to power the
flasher
> LED and it works fine. I'm very interested to see how long the AAs
work vs.
> the 9V..
>
> I also ran across a flashing circuit that's supposed to last a year
at
> http://www.discovercircuits.com/L/lite-flash.htm. If I keep going
through
> batteries or don't get brave enough to attach to the car battery, I
might
> just build it and see how it performs.
>
>

I like the second one. Its simple, but it will last for a long time.
If you use two duracell batteries, it should last well over a year.

>
>
> "Robert C Monsen" <rcsurname@comcast.net> wrote in message
> news:P%MAc.71286$HG.63775@attbi_s53...
> >
> > "NoMailPlease" <DoNotSendMe@AnyMail.OK> wrote in message
> > news:N3MAc.768306$Pk3.569221@pd7tw1no...
> > > I've always had a car alarm and in my new car I figured I'd save
the
> > $300
> > > and just put a flashing LED on the dashboard. There was a blank
> > knock-out
> > > panel on the dash, so I bought a flashing LED and mounting
grommet.
> > I fed
> > > the battery connector to the coin box and this is where I plug
the
> > LED into
> > > a 9V battery.
> > >
> > > The whole thing works great for at least 5 days until the
battery
> > dies. (I
> > > leave it flashing 24 hours per day.) I've seen articles about
> > attaching
> > > flashing LEDs to the car battery, but given my tiny knowledge of
> > > electronics, I'd rather keep this circuit separate.
> > >
> > > My dream now, is to build a better circuit that would allow the
> > flasher to
> > > live for several weeks. I never knew that 9V batteries had such
> > short
> > > lives. If I were to create the most efficient LED flasher
circuit
> > possible,
> > > would it be worth the trouble. Or, would I gain just a few more
> > hours out
> > > of the whole thing?
> > >
> > > If it's worth the trouble, do you know of any plans to build a
> > flashing LED
> > > that runs on AA's, etc??
> > >
> > > Thanks for all your help!
> > >
> >
> > You may want to consider tying into your car battery. You can get
> > cigarette lighter adapters, which will give you 12V. Use that to
power
> > a 7809 voltage regulator (which you can get anywhere electronics
parts
> > are sold, like Radio Shack, for example.) Use the output of the
7809
> > to power your flasher.
> >
> > Your flasher will probably work with 12V with a 150 ohm resistor
in
> > series; it's probably worth a try.
> >
> > The other possibility is rechargable batteries.
> >
> > Regards
> > Bob Monsen
> >
> >
>
>

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