I'm looking at the battery testing section on page 13 in section one and am wondering how a shorted battery would cause too much AC voltage in the system?
Can someone help me understand this?
Thanks!
Nissan Technician
The following user(s) said Thank You: aboudi.naddaf
I haven't got access to my book untill later but thinking about it the way I would look at it is consider the current rather than the the voltage.
An alternator is a 3 phase AC generator that is rectified so there is always going to be some AC ripple. Taking a 120 amp car or truck alternator as an example, with a good fully charged battery and low electrical loads off it might be kicking out less than 20 amps to meet the loads and maintain the battery. If the alternator produces 1% ripple then the ripple will be 0.2 amps.
Now if the alternator is at full field struggling to charge a bad battery and meet electrical loads it will be putting out say 120 amps and the ripple will be 1.2 amp and if we put a multimeter set to AC Volts on the output we will see this as an as an x6 increse in ripple voltage,
In addition a good battery with low internal ressistance will smooth the voltage and current because it is better at providing current/voltage to fill in the dips in the alternator ripple.
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Last edit: 5 years 7 months ago by Andy.MacFadyen.
The following user(s) said Thank You: Noah, Tutti57, aboudi.naddaf
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