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Battery charger voltage ,how high should it go?

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New User

Nov 19, 2022, 9:43 AM

Post #1 of 3 (410 views)
Battery charger voltage ,how high should it go? Sign In

Hi, 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 suppoed to go?

Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Nov 19, 2022, 10:31 AM

Post #2 of 3 (404 views)
Re: Battery charger voltage ,how high should it go? Sign In

How are you measuring voltage?
For battery chargers choose a floating one that shuts off by itself.

If choice or 6 or 12v duh use 12v.

15.8?v Tad high but what are you trusting for accuracy?

You'll have a choice for amps on decent ones use10AMP and wait it out..

All questions for now it really shouldn't drip up that high,


Hammer Time
Ultimate Carjunky / Moderator
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Nov 19, 2022, 12:07 PM

Post #3 of 3 (393 views)
Re: Battery charger voltage ,how high should it go? Sign In

If you are measuring voltage while it is charging you are not measuring the battery voltage, you are measuring the charging voltage. It sounds like that charger was charging at too high a rate.


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