GF's 2013 Mazda 3. This could possibly go in the spark plug section but it's really more about electrical and the charging system.
On the above car, GF said she had the battery replaced maybe 1.5 years ago. Over the last few months she's been experiencing a low battery no start. With engine running the alternator is only putting out about 13.8 volts. Amperage is about 15 amps into the battery and about 15 amps going to the rest of the vehicle shortly after starting. Doesn't change much when tuning on loads like head lights or AC. Little bit higher to account for the additional draw but no change in voltage or current into the battery
Too the car to AutoZone to see what their machine says. Battery checked out ok. Alternator, diodes ok, but reported bad regulator. Gave her a quote for a replacement costing nearly $300 and that was their budget item. They actually where nice and said they don't recommend getting the alternator through them as they are overpriced and Rock Auto or others can provide a replacement for about half the cost
Decided to try pick and pull for $35. What is the chance a car gets junked because a bad alternative. Found a nice alternator that looked clean and the vehicle had some body damage from a small collision. Installed the replacement used alternator and the voltage was exactly the same at 13.8. ????
Unplug the connector and voltage drops to 12.5v. plug it back in and goes up to 13.8v.
Online searing seems to indicate that this vehicle is supposed to have a current sensor on the negative battery post. But I don't see one. Apparently this behavior is an indication it's bad.
The other thing I will likely do is stick my scope on the control line and the feedback line to see if this replacement alternator is receiving and sending the correct signals. Supposedly PWM with duty cycle being the output of the alternator and the feedback being how much load the alternator is being subject too.
Anyone familiar with these Mazda alternator control schemes and what I should check next?
On the above car, GF said she had the battery replaced maybe 1.5 years ago. Over the last few months she's been experiencing a low battery no start. With engine running the alternator is only putting out about 13.8 volts. Amperage is about 15 amps into the battery and about 15 amps going to the rest of the vehicle shortly after starting. Doesn't change much when tuning on loads like head lights or AC. Little bit higher to account for the additional draw but no change in voltage or current into the battery
Too the car to AutoZone to see what their machine says. Battery checked out ok. Alternator, diodes ok, but reported bad regulator. Gave her a quote for a replacement costing nearly $300 and that was their budget item. They actually where nice and said they don't recommend getting the alternator through them as they are overpriced and Rock Auto or others can provide a replacement for about half the cost
Decided to try pick and pull for $35. What is the chance a car gets junked because a bad alternative. Found a nice alternator that looked clean and the vehicle had some body damage from a small collision. Installed the replacement used alternator and the voltage was exactly the same at 13.8. ????
Unplug the connector and voltage drops to 12.5v. plug it back in and goes up to 13.8v.
Online searing seems to indicate that this vehicle is supposed to have a current sensor on the negative battery post. But I don't see one. Apparently this behavior is an indication it's bad.
The other thing I will likely do is stick my scope on the control line and the feedback line to see if this replacement alternator is receiving and sending the correct signals. Supposedly PWM with duty cycle being the output of the alternator and the feedback being how much load the alternator is being subject too.
Anyone familiar with these Mazda alternator control schemes and what I should check next?
