DIYbanter - View Single Post - Keeping car electronics alive while changing battery

chaniarts

Tony wrote:
Jim Yanik wrote:
"Charlie" wrote in
:

"David Nebenzahl" wrote in message
.com...
On 3/25/2010 5:00 PM hr(bob) spake thus:

On Mar 25, 6:07 pm, blueman wrote:

I need to clean the terminals and change out my car battery.
I would rather not lose the setttings on my radio.
But I also would rather not invest in a charger just for this
application.

I have several variable voltage DC power supplies (supplying
about 1A). Could I use such a supply set at say about 13-14V to
supply temporary power while the battery is removed?

Other than getting the voltage and polarity right, anything to be
worried about here or any chance of causing damage (to either car
electonics or to my power supply)?
Set the voltage at 14.0 +/- 0.25V and you should be fine. Like
you indicated, just keep the polarities correct.
Sounds like way overkill on the precision (and voltage) to me.
Someone else here said to just use a 9-volt battery plugged into
the cigarette lighter socket (does this car even have one of
those???). 9 volts might be a mite low, but I'd say just use a
12-volt supply and be done with it. Remember, you're not charging
the battery, only powering the radio's NOVRAM stay-alive power.

That will probably work well if you make sure that opening a door
doesn't turn on interior lights and suck down the battery.

Charlie

what if your car turns off the cig lighter outlet when the car is
off? Will the 9v fixture still hold the memory?

Most don't turn off the cigar lighter.

all 3 of my cars do: a 90, 94, and 96.

Although I do question what
happens when the door is opened and the little 9v tries to power the
interior lights?