I have a 2019 Honda Civic 2.0 liter cvt. How long does it take the alternator to charge the battery if the battery is at 12.3 volts on cold start up?
If you don't drive that long and the trip is less than 2-3 miles, you should take it for 20-30 min spin every week or so to keep the battery charged up, keep moisture out of the crankcase and fluids, and to keep the catalytic converters from "plugging" up.
Don't be afraid to do an Italian tune up here and there.
Almost instantly once the engine is started and the belt and pulleys are moving.
@mrrangerzr1
But what I mean is how long until the battery is fully charged though?
@mrrangerzr1
Because I drive short distances and just wanted to know how long I would have to drive to get my battery back to fully charged
If you have 14 volts + the alternator is working.....
Well lets say the starter pulls approx 300A for a few seconds.
An alternator at idle will charge the battery with around 30A. So it needs about about 10s to put back what the starter used in 1s. So we're talking about a minute. Maybe more if your headlights are on or maybe you turn on the heat or something. That's for a battery that was full.
12.3V is not full. So it will take a while longer to charge a battery back up to 100% (12.6V). This depends on many things like the battery capacity, and the alternator output.
Also cold weather negatively affects how a battery delivers power and how it charges. So you need to consider that as well.
How long are your short trips?
@mountainmanjoe
My short trips are 2 miles away from my house for work and my battery has 500 cold cranking amps
that is pretty short. I would say take it for a proper drive once a week.
... or use a trickle charger