electrical shorts

my 99 ram 2500 has a short its drawing power from somewhere and killing the battery. ?. i have 220,000 miles on the body. do you think the ignition is to blame? if not possible solutions?please help me.!

Reply to
nick6
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Reply to
RamMan

How old is the battery? Any weak component in the charging loop seems to= create havoc, sometimes without any advance notice. To eliminate most of the = accessories you might try (overnight, on a temporary basis) pulling out the fuses. Putting a = ammeter in series with the + battery terminal would allow you to see how much current is being = drawn by the failing assembly. Then (while watching the reading on the meter) begin = to remove/disconnect as many things as possible that run off of 12v. When = you see the measured current drop to almost "0" whatever assembly you just unhooked = is a prime candidate for being the failing unit. Don't forget to unplug /disconnect= the alternator first thing in your elimination process, I have seen these cause similar = problems before. If it began all of a sudden try to remember if there were any other = things done to the vehicle in that time frame and just keep eliminating your vehicles = components that use 12v until you find the one that is creating the "short" and discharging your = battery. Hope this is of help, Joe Brophy. Joe Brophy CountryTech Computer email: snipped-for-privacy@spiretech.com

Reply to
Joe Brophy

I had a similar problem once, it was the cable from the battery to the starter. It looked good, but when I cut it in half, it was green and junkified (TM). The green oxidation over the years had built up resistance in the cable and would drain the battery in a few days. I tried everything else first.

If you haven't change the cable yet, it might be the cause.

Reply to
MoParMaN

OK, I'll bite. How exactly does corrosion inside the cable jacket discharge the battery?

Reply to
TBone

Your kidding, right?

Reply to
MoParMaN

Why is this kidding? How does added resistance on a wire that carries no current unless the starter is engaged going to discharge a battery? Am I missing something?

Reply to
TBone

Residue build up around and in wires cause resististance. Which act like a large capacitor, dissipating electricity. We see it all the time in the computer/electronics field. That's one reason we clean the insides of them bastards. You see the same thing happen if you didn't take a shit for about a month.

Reply to
MoParMaN

because, dickweed..................corrosion in there is generally caused by a BREAK in the INSULATION, which allows water to enter, which then forms the corrosion, said corrosion product is conductive, and discharges the battery, either to ground or to another wire which is also corroded

good grief.........................

Reply to
TranSurgeon

Once again Gary, you jump on a thread and make an ass out of yourself. First of all, we are not talking about a short which is what you are describing here. MoParMaN clearly stated that he didn't even know that the wire was affected until he cut it open so there was no obvious breech in the wires insulation or visible corrosion forming on the outside of the wire in contact with a metal object conducing current to ground. Now perhaps you might want to read my question again and to further clarify it, how does CORROSION INSIDE OF THE JACKET ONLY cause a drain on the battery? You really need to do a little growing up there, dude.

Reply to
TBone

Interesting idea. I'll have to think about that one for a while.

Reply to
TBone

As Gary explained, corrosion doesn't get inside the cable without starting somewhere on the outside.

"Acid residue or a build up of dirt on the battery case can cause a small electrical discharge and weaken the battery, so it should be cleaned off also."

(

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) Anytime corrosion is present, battery drainage can occur. Corrosion inside the cable can cause a split in the insulation, or be cause by moisture getting in through that break. Either way, the battery can drain.

Reply to
Max Dodge
*NOT* x-posted to rec.sports.football.college

M> Residue build up around and in wires cause resististance. Which act like a

I've been watching this thread mainly because everytime I see the title I think, "No, I have some electric socks, but no electrical shorts." As an EE, I am amused by the lack of understanding, on both sides of this thread, of basic electricity. The problem with corrosion in a DC circuit is that the copper oxide has a greater resistance than the copper alloy used in wire. Greater DC resistance causes a greater I*R voltage drop. This converts into either a lower voltage available at the load, perhaps a relay or lamp, that causes it *not* to operate, or generates heat which can eventually cause the insulation to melt or burn causing a potential short. Unless the AWG of the wire is waaaaaay underspec'd even a 25% surface area corrosion shouldn't make much difference at DC.

It takes a potential difference between two points before current can flow. Basic Kirchoff's Law. Resistance never looks like capacitance to a DC circuit. Capacitance in series will *open* a circuit. Capacitance in a parallel circuit, i.e., capacitance between +12VDC and ground, will tend to smooth the waveform in state changes, eg. turn on/turn offs. It can't cause a short, unless it ceases to be a capacitor and becomes a resistor.

OK, end of rant. It grinds me to say it, but I gotta go with TBone this one time. End of electrical shorts and on to more heated seats and swamp butt.

Reply to
Langerhans

Agreed to all that you say, except that you forgot to mention the possible drainage from battery acid leakage. This may be what cause the corrosion to begin with. I'll counter this with the condition that I doubt it would completely drain a battery unless left for an extended time.

Further playing devils advocate, I'd suggest that the resistance from a corroded cable, clamp etc. could look initially like the battery was drained.

I'll end by saying that in disregard of all known electrical theory, DC current in a 12v negative ground system acts as it sees fit at times, and almost anything can happen if the system is not maintained well.

Reply to
Max Dodge

If you are talking about a pool of battery acid somehow lying between the + and - terminals, that would be a fairly high resistance, although somewhat conductive. (Mostly it would depend on the shape of the pool.) I would imagine that at 12V, it would draw on the order of a few milliamps. Certainly much less important than the inherent self-discharge rate of a lead-acid battery.

Depends on how you "look". A voltmeter between the terminal and the clamp should reveal no potential difference. If it does, make a better connection by whatever means works.

'Lectric thangs airn't trustworthy. Most of the time, they are compelled to follow the laws of physics, and when they misbehave there is usually a good reason, if you know where and how to look. Except the time I was standing inside the transmitter of an FM station tweakin' on stuff, and the 25KW final tube decided to jump out and bite me in the calf through a faraday shield (HD grounded aluminum cage). I took 7200V at about 4A at 100MHz. Burned a 2" hole in my calf, vaporized the frizz on my socks, and melted the sole of my Hush Puppies. Even the factory engineers from Collins couldn't figure out how that happened.

Reply to
Langerhans

I tend to agree, however this is ther main reason proper battery maintenance includes washing the battery. Thus I have to conclude that the drainage is significant enough to affect battery performance.

Most certainly.

That hurt just reading about it.

Reply to
Max Dodge

not a month, I hope.. *g*

mac

Please remove splinters before emailing

Reply to
mac davis

HAAAAA, you owe me a new monitor.

Reply to
MoParMaN

Na, just a week while I was at the VB developers conference in Boston.

Reply to
TBone

we have been in the 2-way service for over 55 years, and I want to see just one "LONG" in their radio instead of "shorts" and I also want to know how the internal corrosion will discharge the battery?????????? just asking, and willing to learn... carl & dee yankees in alabama vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv

Reply to
carl wesser

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