>> He bought a new battery the other day, connected it up, tried to start the
>> car a couple of times and it turned over okay (it didn't start for some fuel
>> related reason or other). Then, while trying for the fourth time he saw a
>> big spark and the positive terminal on the battery melt! I mean the metal!
>> I've had a look at the car and agree that it's pretty hard to connect up the
>> wrong way round and we treble checked the battery is of the correct type.
>
> Hooking up the battery backwards probably wouldn't have hurt it (the battery),
> but all the electronics in the car would have gotten toasted. I don't think
> this was your friends problem.
My knowledge of automotive electronics is generally limited to knowing
that voltmeters aren't as cool as ammeters for a reason I've still never
been able to internalize, but I've had some practical experience that might
shed a little light (if occasionally in blinding blue flashes of short
duration) on this issue.
1. Hooking Batteries Up Backwards. As Pat says, this does nothing to
the battery but it makes various components in the car's electrical
system unhappy. I got all confused on a Chevrolet one time, after
having read so many "WARNING -- NEGATIVE EARTH" signs in my LBCs, that I
figured, "Well, then 'Merican cars must be positive earth." Nope. Good
thing Chevy parts are so cheap, I got a new alternator and a new voltage
regulator for under $40. Used the same battery for over a year, till
I sold the car just last month. (Waitaminit... Come to think of it, when
I had the battery in backwards, there *was* a little sizzling smoke coming
off one of the greased terminals... any ideas on why? No, I didn't use
bacon fat, I used the Bosch electrical terminal grease.)
2. Hooking JUMPER CABLES Up Backwards. This is another ball of falafel
altogether. Had a friend years ago with a Saab, which had a leak in
one of the electrical circuits somewhere, and all the volts would
trickle out over time. It seems that about once a fortnight I'd pull up
next to the Saab with my Midget, haul out the jumper cables (I'd put
them in my Midget thinking I'd need to receive jump starts, but I
was always the donor), hook up the Swedish Wonder, and crank away.
One day late in the relationship, I wasn't paying attention; I'd
become careless; I fecklessly hooked up the red to the + and the black
to the - on my car, then hooked up the red to the - on the Saab. So
far so good. When I brought the black cable near the + on the Lutefiskmobile,
there was an almighty GZZZZZT that had me looking up expecting to hear
the voice of Jupiter (or maybe Thor would be more appropriate). A
blinding blue flash made me leap back from the car.
"I dunno," I said. "Maybe the MG remembers Lindisfarne." I tried again.
Another GZZZT, this time with blobs of hot lead spewing off the by-now
holed and eaten battery terminal like the tears of a baby dragon whose
big sister has just snatched its helping of flame-broiled maiden-on-a-spear.
"Oh," I said, looking more carefully at the layout. "I see. I have the
wires reversed." We tried again. The car still wouldn't start. My
friend released me from my obligation and sent me home; she later called
AAA, who kindly informed her that the automatic transmission on that model
year had a lockout so that you couldn't engage the starter unless it was
in Park.
At least I didn't do the dumbest thing that day, but I came close.
So Jon, did your mate perchance hook up a jumper to try to get the car
to crank?
--Scott "Red to black, black to red, GZZZZZT FOOM!" Fisher
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