Battery charger voltage, is this normal?

Nov 19, 2022
Hi everyone!
I bought a car battery charger and plugged it on my car battery to test it (normal battery not AGM). my battery was probably already fully charged because I drove with my car just before using the charger. So this happened: the voltage on the charger started at around 12v? (not sure exactly... maybe a bit lower) and then slowly went up to 15.8v in about 5 minutes then I unplugged it because I wasnt sure if that is normal, I never charged a car battery before.

Is it normal that the voltage went that high and how high is it supposed to go?
Does the charger come with a user’s manual? If yes, what does it say? If it is a smart charger like CTEK then it is normal. Again, check your user’s manual.


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Most "recondition" or "recovery" modes will bring a battery to over 15v for a period of time.

What charger?