i was running my bII i noticed i knocked the cable off ( it loose cuase if i leave the cable on while it sits for a while it drains for some reason old battery i guess) and the engine didnt skip a beat the year is 1987 for some reason the battery light didnt light up ethier also all electical stuff works too i had no clue it would run with out a battery i knew older cars did but i figured the ecm and stuff would fail if the there was no battery imput this is pretty wierd could there be somthing wrong cuasing a short for somthing like this to happen or is the bronco II really that out dated that it just works with out a battery also shouldnt the battey light come on if the battery is missing?? lol i know the light it self works cuase its on if the key in on but the engine isnt any ideas??

 

If your alternator is working correctly, that appears to be functioning exactly as it should. The battery light will come on when the voltage drops below what it should be at, like when you turn the key on without the engine running, there is a draw to the battery, and no input voltage from the alternator. The alternator will provide the necessary current to run the efi, and also provide enough voltage that the battery light shouldn't come on, as it should be reading the voltage from the alternator, which is higher than the batteries anyways. I guess popping the cable off was just a good test that your alternator is in good shape.

 

great thanks for some reason i though cars didnt run with out a battery i though ethier the battery was nessary for the compleletion of some vital circut of the alernator didnt make 14v D.C. but A.C. to charge the battery which we all know woulndt work with any of the motor components

 

Would it run without the negative? I've always thought a car won't run without the negative, but it can run without the positive.

 

And the difference is??? The only reasons the battery is there are: 1) provide storage capacity for when the vehicle isn't running, and 2) provide a filtering effect for the electrical system. You run a small risk of damage to electronic components (esp newer vehicles) running without the battery. The battery removes or lessens most of the spikes and surges that occur in the electrical system. Yes, it will run with the neg. removed.

 

I guess it's always been in my mind ever since I was a little kid that it couldn't run without negative lol. It makes sense that if it runs without the positive it would run without the negative, but I haven't ever tried it.