DC current appears at alternator "B" terminal. In addition, the charging voltage of this alternator is regulated by the battery voltage detection system.
Alternator Management System
Alternator management system controls the charging voltage set point in order to improve fuel economy, manage alternator load under various operating conditions, keep the battery charged, and protect the battery from over-charging. ECM controls generating voltage by duty cycle (charging control, discharging control, normal control) based on the battery conditions and vehicle operating conditions.
The system conducts discharging control when accelerating a vehicle. Vehicle reduces an alternator load and consumes an electric power form a battery.
The system conducts charging control when decelerating a vehicle. Vehicle increases an alternator load and charges a battery.

Rather than posting, check repair procedures:

Kia Optima: Repair procedures - Charging System - Engine Electrical System - Kia Optima TF 2011-2025 Service Manual

 

What ended up being your fix? Ours just died Thursday and replacement alternators aren't working.

 

Has anyone had success with this? My 2012 Kia optima is not charging. I've checked virtually everything. I am leaning towards the ecm. The battery indicator light on the dashboard does not illuminate when you turn the key on. It only comes on once the battery is just under 9 volts.

 

Our problem ended up being the mechanic received 2 bad alternators from their distributor.

 

The mechanic had a hard time finding alternators. Their supplier had 2 rebuilt (the two bad ones). They finally were able to source a new one. That resolved the problem.
The rebuilt ones would only produce 12V.
The AC compressor has crapped out too. (next project)

 

My 2012 EX is doing the same thing..
One night before I was moving from Oregon to Washington my battery was dead.. So I asked my son-in-law if he could jump me. While I was doing something else he hooked up his jump Box to my battery the wrong way (mix the cables) and I heard this horrible screeching noise. He assured me that he didn't do anything Which I believed them because I didn't see any sparks or anything but the jump Box making a squealing noise. So I drove to the store and I noticed that my lights kind of that my lights kind of dimmed a little and then went back to bright didn't think anything about it. Next day I was driving to go pick up my u-haul and have my car loaded onto the car trailer and my battery light came on again I didn't really think about it because I was busy with this move To Washington. So After I took the car off the car trailer trailer I shut the car off and then went back to it and it when it started all the lights came on on the - lights I'd never seen before. I figured it was a dead battery because we couldn't jump it so I went and bought a new battery. I drove about 5 miles with the new battery and it started to get sluggish and all the lights started coming back on and I pulled over and it died. So I assumed the alternator was bad I got an alternator put it in put it in drove about a mile down the road and the same thing happened I couldn't go faster than 25 miles an hour couldn't go over 2000 RP m's or 2000 rpm's. I stirred it to the side of the road and it died. I can't figure out what's going on with it. After reading this I'm wondering if I bought a bad alternator alternator. Or or did my son-in-law fry my ECM?

 

My 2012 EX is doing the same thing..
One night before I was moving from Oregon to Washington my battery was dead.. So I asked my son-in-law if he could jump me. While I was doing something else he hooked up his jump Box to my battery the wrong way (mix the cables) and I heard this horrible screeching noise. He assured me that he didn't do anything Which I believed them because I didn't see any sparks or anything but the jump Box making a squealing noise. So I drove to the store and I noticed that my lights kind of that my lights kind of dimmed a little and then went back to bright didn't think anything about it. Next day I was driving to go pick up my u-haul and have my car loaded onto the car trailer and my battery light came on again I didn't really think about it because I was busy with this move To Washington. So After I took the car off the car trailer trailer I shut the car off and then went back to it and it when it started all the lights came on on the - lights I'd never seen before. I figured it was a dead battery because we couldn't jump it so I went and bought a new battery. I drove about 5 miles with the new battery and it started to get sluggish and all the lights started coming back on and I pulled over and it died. So I assumed the alternator was bad I got an alternator put it in put it in drove about a mile down the road and the same thing happened I couldn't go faster than 25 miles an hour couldn't go over 2000 RP m's or 2000 rpm's. I stirred it to the side of the road and it died. I can't figure out what's going on with it. After reading this I'm wondering if I bought a bad alternator alternator. Or or did my son-in-law fry my ECM?

The vehicle may need to be scanned for codes because it sounds like vehicle went into a limp mode to restrict rpm's. If no codes then check charging system.

 

I

 

I'm sorry to say that those of you who were told by your "mechanics" they were given bad alternators...... you were lied to. What most likely happened was they finally realized your car has a battery and an alternator management system to save on gas mileage. And on your positive battery cable end there is a "battery fuse" (Dorman part # 926-011) it costs around $10 at ALL local auto parts stores or the internet. And with a simple ohm meter test they found it was bad. Sometimes they will melt sometimes they will burn thru the blade like most fuses but that IS YOUR PROBLEM. now did you really need that alternator. Maybe it could've burned the fuse or just the fuse was burnt. Anyway hope this helps. Also there are cases of ground wires and defective alternators but 99 out of 100 is this 926-011 battery fuse. You need a 10mm n a 12mm to replace it Simple

 

But then you need to figure out, why is the car burning through fuses? Will my car blow another fuse in the middle of a road trip?

 

Maybe in your odd case. But as you'll see I posted most cases. If you keep burning thru then I'd star by asking questions of accident and history etc. And probably follow your harness ... so probably in your case follow the repair instructions. Yours is a case based on your car not "design" like most of the cases.