Inquirer, the three connections you posted would not complete a circuit and no current would flow, and the cables would not of smoked. There must of been another connection, like the negative of the good vehicle ( from the frame, or engine block, or some metal on the engine such as the alternator mount bracket, or the negative of the battery of the good vehicle ) to the negative of the bad vehicle such as ( the frame, or engine block, or some metal on the engine such as the alternator mount bracket, or the negative of the battery of the bad vehicle ), in order to complete the circuit so current would flow and cause the cables to smoke.
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In the old days I would of included the possible negative connection of touching the bumpers together, but now days they are almost always plastic or plastic coated.
BTW, Back in the day, when cars had metal bumpers that were bolted to metal frames, I once jump started a bad battery when no one had any jumper cables, by touching the metal front bumper of my car to the metal front bumper of the bad car, and then holding the L type lug wrenches from both cars touching together the screw driver blade ends ( the large flat blade ends for removing hub-caps ) and having the lug ends each touching a positive so the two L lug wrenches made the + connections ( with me touching the positive lug wrenches, aware that 12 Volts would not hurt me but I did not touch the vehicles because there frames were negative, and I had on dry boots ), and the owner of the bad car cranked his car while I held the lug wrenches this way. It worked and the bad car started. There is one for MacGyver.
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Back to the topic at hand, Inquirer, assuming you did make some means of connecting the negatives to complete the circuit ( because the cables did smoke, so the current did flow ), what you described is placing a very heavy load on the good vehicle. Fortunately for the owner of the dead vehicle, what you described did not actually apply a complete reversal of polarity to the dead vehicle and therefore did NOT damage any thing in the dead vehicle. However, you placed a very heavy load on the battery and the alternator of the good vehicle, ( basically a short with the current limited by the very low resistance of the cables and there connections, and the ability of the good battery and alternator to supply the current ).
WHAT YOU HAVE TO NOW WATCH OUT FOR IS THE POSIBALITY THAT YOU DAMAGED ONE OF THE HIGH CURRENT DIODES IN THE OUTPUT CIRCUIT OF THE ALTERNATOR OF THE GOOD VEHICLE THAT HAD THE ENGINE RUNNING WHEN YOU PLACED THAT LARGE LOAD ON IT.
WHAT CAN SOMETIMES HAPPEN WHEN YOU ABUSE THE OUTPUT DIODES OF AN ANTERNATOR THE WAY YOU DID IS THAT ONE OR MORE OF THE DIODES WILL BECOME ELECTRICALLY LEAKY IN THE REVERSE DIRECTION AND THIS WILL PLACE AN ELECTRIC LOAD ON THE BATTERY THAT WILL SLOWLY DRAIN THE BATTERY WHEN THE VEHICLE IS NOT RUNNING. USUALLY THIS ONLY SHOW UP WHEN YOU LET THE VEHICLE SIT FOR 2 OR MORE DAYS WITHOUT EVER RUNNING IT. BECAUSE MOST PEOPLE USE VEHICLES DAILY, IF IT IS A LONG TIME BEFORE THE GOOD VEHICLE IS LEFT TO SIT FOR 2 OR MORE DAYS, IT CAN BE A LONG TIME BEFORE THIS SHOW UP. HOWEVER IF YOU DID DAMAGE AN OUTPUT DIODE THIS WAY, THE FIRST TIME THE GOOD VEHICLE IS LEFT TO SIT FOR 2 OR MORE DAYS WITHOUT BEING RAN, IF THE BATTERY APPEARS DEAD, IT IS MORE THAN LIKLEY THAT THE ALTERNATOR IS DRAING THE BATTERY AND SLOWLY DISCHARGING IT BECAUSE OF A BAD LEAKY OUTPUT DIODE.
Most alternators in modern vehicles now days use pulse with modulation of the output and are not as prone to damaging the output diodes as the older alternators of the 1970's and 1980's that used a simple linear voltage regulator would have. So the chances are your alternator is probably OK. But the only ways to find out for sure is to have someone do a leakage test to see what the output of the good alternators reverse leakage is when its positive output is connected to the positive of the battery and of course its frame ground is connected to the battery ground, or just let the vehicle sit for 2 or more days and see if the battery gets discharged and the vehicle will not start.
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Back in the day, before modern alternators with pulse with modulation, it was common to damage one or more of the output diodes of an alternator by jump starting a dead vehicle, with the engine running in the good vehicle, and the alternator of the good vehicle could sometimes put out too much current when the bad vehicle cranked, and damage one or more of the output diodes of the good vehicles alternator, and the bad diode(s) would become electrically leaky and draw some current when the good vehicle was shut off every time after that had happened. Often it would be a long time such as a month or more before the good vehicle was not use 2 or more days in a row, and only then would the good vehicle not start. Because of the long delay, it was sometimes hard to make the connection to how the output diodes were damaged.
It is still not a good idea to run the engine of the good vehicle when jump-starting a bad vehicle, because even with the polarity connected properly, there is a slight chance of the output of the good alternator putting out too much current and damaging one or more output diodes.
You should not run the engine of the good car when you jump start a bad car. With the engine of the good car not running there is no chance of damaging the alternator of the good car.
