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
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)?
I had to do this on my father in law's cadillac where the whole car
gets a brain transplant when you disconnect the battery. I just
connected it up to my car with jumper cables, swapped the battery and
hooked it back up. Just be careful not to let anything short out.
This caddy has a "jumper" terminal away from the battery so the hookup
was easy. I just put the terminals in heavy leather work gloves
because I had that handy.
This sounded a little like overkill, but is sounding better all the time.
No worry about cig lighter is on, or door is open for lights. And (not
mentioned except by you) disconnected hot battery terminal can't be
Temporarily connecting a 9V battery to 12V doesn't do anything?
That depends on what the voltage requirement of the Non-Volatile RAM.
Lot's of auto computers run partially on regulated 5 volts powered by
the 12vdc battery. If so, the 9vdc would work just fine. Not to
mention that most non-volatile ram doesn't need full rated working
voltage to hold memory. I've seen lots of 5VDC ram that only need 2.5
to 3 volts to hold the memory.
On 3/25/2010 5:00 PM hr(bob) email@example.com spake thus:
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.
You were wrong, and I'm man enough to admit it.
Most recent cars don't call it a cigarette lighter any more, they call
it a 'power outlet', and it has a little flipper cover over it. Some
switch, some don't. Usual convention is a picture of a battery for
non-switched, and a picture of a key for switched. A lot of cars don't
even have one. Other alternative is to go to Harbor Freight, and buy
some big alligator clips and some wire, and just make it so you can clip
it on the next connector and available ground point downstream from the
My truck and car each have two power outlets. One of the ones in my truck is
a "cigar lighter" and one is an aux power outlet. IIRC, one is switched, but
I don't remember which one. Neither of the outlets in the car is switched.
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