Does someone have an idea on why the charging test is high? Do I need to replace the alternator?

 

Are you sure that's high? Cause it's supposed to be in the 14v range when the alternator is in high output mode (ie charging).

What voltage were you expecting?

 

I'm not sure what Voltage I was expecting. I just saw the charging test was high. After the car sits over night. The changing test said high. After driving it says normal.


All summer we have been having a starting issue, had trouble starting the car in the mornings only, since it has got colder out, the car starts no problem. So we bought a tester to try and figure out what is going on.

 

How old is the battery?

 

About 3 months

 

that ripple shows me that a diod is sticking. when the car worms up the diod opens. time to get a new alt.

 

had a feeling i would need a new alt. do you know what the ripple should be around at?

 

If the meter is low quality, the measurements at the limit are always suspect. How old is your battery? Go to a garage or big parts supplier and get both the battery and alternator tested with professional gear first.

As a general matter, I don't think 21mv of ripple is a problem. The diodes will always leave some AC ripple but that will vary among cars. If you have a scope to look at the waveform that helps. I would be concerned at over 500mv but maybe over 100mv depending on the car. There are all kinds of opinions and references on the internet but here are a few:

https://www.picoauto.com/library/aut...le-diode-test/
https://www.tirereview.com/alternator-ripple-testing/
https://www.hagerty.com/articles-vid...ing-system-pt2

If the alternator runs too much voltage (say roughly above 14.7v in typical cars), then you run the risk of boiling the battery, which seems to be what the test is indicating. Before replacing parts, try cleaning the electrical contacts to see if excessive resistance is screwing up your system calibration.

Winter salt and water cause terrible corrosion in the Fit engine area, moreso than I have seen on my other cars. You might get better electrical performance by cleaning the major power contacts (e.g. battery terminals / clamps, large wires at fuse boxes, all contacts at the alternator, major grounds to body and engine, etc.). In particular the alternator will have contacts for positive, negative and computer; clean them all. As you have starting issues, clean the contacts for the starter also if accessable.

You can do a "voltage drop" test before and after with a simple DMM. This can improve performance and life of battery/alternator/starter, which matters for you as your car has a tiny battery and suffers very cold Canadian winters.

Always use extreme caution around the battery with goggles, gloves, etc. They can explode or seriously shock, so do your research on safety before continuting.

 

I agree with Fitting. Get a better test done. 20mV is not much of a ripple.

 

It would be interesting to know the charging system voltage when it fails. That would make a big difference in the diagnostic approach to this problem. If the voltage I low, I would suspect a slipping belt due to a weak tensioner. If it is too high, I would suspect a bad voltage feed back line to the BCM or a bad regulator inside the alternator. Again without knowing the voltage at the time it fails, it is difficult to know where to start looking.