Strange things happened to my 1994 Camry. 1) Car would not start - no click, engine would not turn over. But I noticed some low voltage interior lights still on. 2) Jumped it. Started right up. 3) Took it on the road to charge the battery. 4) ABS light cycled on and off. 5) Felt like the timing was being cut back from 1500 to 1200 rpm. Could not go over 20 MPH. 5) Was able to drive it about 1/4 mile, but the car died while moving - fortunately coasted back into my garage. 6) Went out to jump again later, same symptoms. 7) An hour later, tried to start without a jump, and it started! No ABS warning light. 8) Replaced battery and checked ground. Battery was toast, alternator fine, ground ok. No symptoms since, other that several dash lights no longer working. What happened? What was wrong? Is it fixed for good?
Besides supplying juice [my dear departed father’s term] to start the car the battery stabilizes the voltage of the electrical system.
The alternator does not put out steady current and the many electrical devices in a modern car do not draw current at a steady rate.
So without a good battery to even things out the voltage can jump allover the place and cause all kinds of havoc.
This is why one should NEVER disconnect the battery while the engine is running on a modern car to test the alternator.