Any one or more of the following:
-nothing
-battery explosion (and resulting damage possibly including permanent injury)
-fire
-blown fuses
-burned wiring
-damaged alternator or AC compressor
-damaged electronics including such things as radio, engine computer, body computer, gages, ignition module, transmission computer, antitheft computer, door latches, airbags, etc.
you can blow fuses or the battery Possible computer damage.
You cross the battery.
Overheat he battery to the point of busting it.
It will be reverse biased and will not light.
The voltage of a battery with three cells connected in series is the sum of the individual cell voltages. If one cell is connected the wrong way round, the total voltage will be reduced by the voltage of that cell.
Engine won't start
Nothing as long as it was a 12 volt battery.
It may do this if you have the leads to the meter connected to the wrong ends of the battery.
No, not the battery. But anything that has a diode, transistor or is in any other way dependent on polarity may be fried... including your alternator.
try a new battrey and check if it works. can i know what car is is?
You can't recharge it hooked up in reverse. You will destroy the battery or the charger if you try it.
charger i had was wired wrong. soon as it was plugged in the charger stopped working. if wires are wrong it just will not charge and can be dangerous!