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Author Topic: reversed battery terminals  (Read 1630 times)
Devin & Amy
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« on: August 01, 2006, 01:27:45 PM »

hi all,

i hooked up all of the 12v system, checked and double checked everything. I have a meter at the distribution point it read 12.6v.
When I closed the switch at the batts all my fuses popped. So I assumed I had underfused the system(20A) but was pretty sure I hadn't. I checked polarity again.
i put in a 30A fuse in one of the purely light circuits. 3 lights. It didn't pop. So I went to turn the lights on and they were smokin.The wires melted in about a minute. I ran back pulled the fuse and completely rechecked the entire system. I couldn't figure it out. I tested the battery , tested the voltage at the box. I kept coming up with the right voltage.

When I was sitting next to the batts for the umpteenth time I put the red lead on the neg. post and put the black lead to the chassis,bingo 12.6v.

why, how, what the heck?

Anybody have this happen to them?

Devin
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Devin, Amy, and the kids!!
Happily Bussin'!!
TomC
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« Reply #1 on: August 01, 2006, 01:41:14 PM »

OOPS!  On a D/C car type circuts, black is ground and either white or red is positive.  This is one way they keep from getting A/C and D/C mixed up.  Sorry to here about your mistake.  Make sure next time to make a diagram of what you disconnect, then this might not happen again.  Good Luck, TomC
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Tom & Donna Christman. '77 AMGeneral 10240B; 8V-71TATAIC V730.
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« Reply #2 on: August 01, 2006, 06:51:00 PM »

Yep.  I'll echo what Tom said.  He's right, in d.c. circuits, red is positive, and negative is usually black.  While we're on the subject of electricity, I will also mention that troubleshooting is often easier if you use a Simpson model 260 or similar analog meter, having a "needle", rather than an electronic or digital meter.  The digital meters tend to be so sensitive that often a little stray voltage that feeds back through a coil, winding, or bulb will mislead you.  Another thing, any electrician who claims he never burned the end off a screwdriver is either lying or he just hasn't been at it long enough! FWIW
Dennis
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jjrbus
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« Reply #3 on: August 01, 2006, 06:53:39 PM »

Most of the  people who have never done something like that, have never done nothing, if you never do anything you cannot make a mistake. The rest are just bald faced liars.
 If we learn from our mistakes, I am well on the way to becoming the smartest person in the known universe.


                                                                                                         Work?/Play safely Jim
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Devin & Amy
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« Reply #4 on: August 01, 2006, 06:53:58 PM »

Hi all,

Didn't make myself clear. The battery was wired internally backwards. The positive stud was the negative stud. Took batt back to napa and exchanged for a new one, now no problems.
 Devin
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Jeremy
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« Reply #5 on: August 02, 2006, 01:43:42 AM »

Devin

Yeah, I wasn't sure what you were saying, but I was sure you hadn't simply connected it backwards. in the UK at least the battery terminals are different, so connecting backwards shouldn't be possible.

By the way, most digital voltmeters display a minus sign (-) if the leads are connected the wrong way round - if yours does something else, or doesn't do anything at all to indicate a negative voltage, it's worth remembering that in future.

Jeremy
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« Reply #6 on: August 02, 2006, 05:17:54 AM »

Actually the battery was probably not "wired" backwards, instead, some doofus at it's factory probably charged it backwards.  Batteries can actually take, and hold a reverse charge, and a whopping one at that. It's a mistake I've made... Smiley
If this little episode screwed up anything, you may be able to get the battery dealer to "help" out with the fixin, as it is a really stupid mistake on their part...

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DrivingMissLazy
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« Reply #7 on: August 02, 2006, 05:22:04 AM »

And that is really easy to do, especially if the battery is totally discharged. Don't ask me how I know. LOL
Richard


Actually the battery was probably not "wired" backwards, instead, some doofus at it's factory probably charged it backwards.  Batteries can actually take, and hold a reverse charge, and a whopping one at that. It's a mistake I've made... Smiley
If this little episode screwed up anything, you may be able to get the battery dealer to "help" out with the fixin, as it is a really stupid mistake on their part...


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Happycampersrus
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« Reply #8 on: August 02, 2006, 05:47:33 AM »

I changed out a starter TWICE, because of that. It was at work on a old forklift we bought at auction. No one knew anything about the lift except it wouldn't start, so I assumed they had the wrong starter on the 4-53 engine. Turned out the joke was on me. LOL.
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Dale
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Len Silva
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« Reply #9 on: August 02, 2006, 05:53:31 AM »

Some batteries are available with different post configurations.  My guess is that it was put in the wrong case at the factory.

Len
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« Reply #10 on: August 02, 2006, 06:11:36 AM »

Most of the  people who have never done something like that, have never done nothing, if you never do anything you cannot make a mistake. The rest are just bald faced liars.  If we learn from our mistakes, I am well on the way to becoming the smartest person in the known universe.  Work?/Play safely Jim


Jim -  I'll have you know that I have NEVER made a mistake, except once.















Then I discovered that I was mistaken!   Grin Grin Grin Grin Grin

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RJ Long
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