Re: Can a dead battery damage an alternator? For starters, mine did. Even if not originally, it was fitted as we had fried the alternator quite a few times. The ignition light was the only clue of a defect in the charging system.
I am aware of the cutout function, and if any of the coils opened the ignition light would come on. after staring at it for a few years my father decided on the ammeter and using of manual control. This was in the 70s, when few mechs in Calcutta knew much about the electrical system. Quote:
The main fuse does all this?
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Lack of overcurrent protection has the risk of any of this, or all of this, or any combination thereof.
In any closed-loop system an overcurrent condition will fry the weakest component. Hopefully a fuse or a breaker. Mechanical malfunctions aside, a break in the field will stop current from flowing through each component and this protects the alternator as well as connected components. Quote:
You 'trickle' charge a Lead Acid Accumulator to a terminal voltage above its norm
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As long as the overvoltage is within norms (14.7 max for 6-cell 12V LA, IIRC) it should be fine for the battery, and will simply demand less current. Fault conditions excepted, a normal car electrical system with engine running will not generate more than that. Given this terminal voltage a car battery cannot be damaged or overcharged.
Any CV charging system depends on a certain overvoltage to properly charge the battery. In case of small deficit the current flowing can be calculated by the potential difference between the battery and the source, divided by the impedance of the total system. As the battery rises to charge its internal impedance decreases (which increases risk of overcharging for large potential differences) but cell voltage rises much faster, reducing the potential difference to reduce the system current.
Battery in deep discharge state cannot be handled the same way as a partially charged battery. Nor are the calculations valid because the currents involved are very high and system non-linearity comes into play. |