Hyundai Forum: Hyundai Performance Forum banner
1 - 9 of 9 Posts

· Registered
Joined
·
5 Posts
Discussion Starter · #1 ·
The battery light is turned on most of the times when driving. The parking brake lamp is also on.


The alternator is charging 16V to the battery under load (heaters on, full fan etc). Is 16V too much?


I have replaced the battery with a brand new and the problem persist. The old battery died while the car was driving and it ended with 11.90V in the battery, the car would not start after this obviously.


Where do I begin? I would imagine and hope I could find a relay for the alternator that is burned up and can replace it easily. But I am not sure where to find the relay specifically for the alternator, and what pins would I measure?



Thanks
 

· Super Moderator
2000 model Hyundai Lantra GLS 2.0 (G4GF) factory 5 speed manual. Fully optioned. Most things work...
Joined
·
148 Posts
16v is too much. There are diodes in the alternator that act as a voltage rectifier/regulator. If you set your multimeter to AC while the engine is running and get any reading other than zero at the battery terminals, one of those diodes has failed. Ideal voltage in DC should not exceed approx 14v under load (battery in charging state with onboard accessories running etc) Go to a JY and pick up a used alternator. Alternators are easy enough to swap out.
 

· Registered
Joined
·
5 Posts
Discussion Starter · #3 ·
16v is too much. There are diodes in the alternator that act as a voltage rectifier/regulator. If you set your multimeter to AC while the engine is running and get any reading other than zero at the battery terminals, one of those diodes has failed. Ideal voltage in DC should not exceed approx 14v under load (battery in charging state with onboard accessories running etc) Go to a JY and pick up a used alternator. Alternators are easy enough to swap out.
Alright, thanks for the tip. Will check if the alternator is producing AC. Do you think the brand new battery can be damaged if driving around while the alternator is charging 16V?
 

· Super Moderator
2000 model Hyundai Lantra GLS 2.0 (G4GF) factory 5 speed manual. Fully optioned. Most things work...
Joined
·
148 Posts
It may be ok if the alternator hasn't boiled the battery dry on any of the cells. Hard to tell without trying, but if you haven't run it for long under those conditions it is possible it hasn't been damaged...
 

· Registered
Joined
·
5 Posts
Discussion Starter · #5 ·
It may be ok if the alternator hasn't boiled the battery dry on any of the cells. Hard to tell without trying, but if you haven't run it for long under those conditions it is possible it hasn't been damaged...
Ok, the car was driven only for 2-4 min after the new battery got in, so it could be fine hopefully. Just out of curiosity, do you know what is getting damaged inside the battery cell if it starts boiling?
 

· Registered
Joined
·
5 Posts
Discussion Starter · #6 ·
It may be ok if the alternator hasn't boiled the battery dry on any of the cells. Hard to tell without trying, but if you haven't run it for long under those conditions it is possible it hasn't been damaged...
Ok, the car was driven only for 2-4 min after the new battery got in, so it could be fine hopefully. Just out of curiosity, do you know what is getting damaged inside the battery cell if it starts boiling?

Is there any voltage regulator relay that could be burned that I could check before starting to spend more serious amount of effort into replacing the alternator?


Thanks!
 

· Super Moderator
2000 model Hyundai Lantra GLS 2.0 (G4GF) factory 5 speed manual. Fully optioned. Most things work...
Joined
·
148 Posts
All of the rectifier and regulator components are inside the rear housing of the alternator. Google images for Valeo Hyundai alternators. The parts themselves are relatively cheap but you will still need to remove and install the alternator and in some cases aren't as easy as removing screws etc to replace the regulator and rectifier. In the alternator I have the rectifier is nothing more than some standard diodes bridged across a couple of terminals but you will still need the skills to test and desolder them and know how to read their values or research them.
 

· Super Moderator
2000 model Hyundai Lantra GLS 2.0 (G4GF) factory 5 speed manual. Fully optioned. Most things work...
Joined
·
148 Posts
And to answer your question about what is inside of a car battery - there are interlaced metal plates that are bridged together. The plates that produce the positive ions are treated with lead dioxide while the negative plates are treated with a spongy lead active material. Overcharging them or the plates themselves not being submerged in the acid causes these coatings to break down, reducing their ability to hold charge and their efficiency.
 
1 - 9 of 9 Posts
Top