[M-terkait]

I've got a warning message about low voltage battery yesterday while driving on the highway, after stopping at home i went to secret menu and showed battery v11.5, and thats very low but not sure why the car says start the engine and i was doing around 60mph when i got it .

Is it a bad IBS or Alternator?
Im not sure where is the IBS though if its the only thing needs replacing.

[M-terkait]

After I started inspecting the car. I noticed that the red cap for battery terminal near fuse box is melted and saw smoke coming from the terminal. the plastic on the terminal was melting which explains the bad smell when turning on AC; I was getting since a few weeks ago.

when turning off the car it doesn't happen.

I cleaned the contact points with a knife and after that, the car started somehow better and it charged up from 11.1v to 13.2v for few revs in a minute which is weird but it was still smoking.

[jv004]

I think there's a recall for something related to this. Mine got replaced under this recall, should look to see if that's related.

[M-terkait]

I think the alternator is shorted internally. that causes all this heat.
I'll test on alternator after work. With multimeter as far as my research

Test plan:
Ill turn ign ON
Probe1 red Alternator, probe2 Red jumper terminal
Probe1 ground, probe2 alternator case/housing

[Billfitz]

The alternator should either work or not. A loose wire between the alternator and the battery would explain the heat and the low battery voltage. I don't know how the wiring runs, but since the alternator and the charging post are both under the hood it makes sense that the alternator wiring connects to the charging post, which then connects to the battery. That would seem born out by the heat there. With the car running measure the voltage at the alternator, at the post and at the battery. They should all be the same, roughly 13v. If not there's a bad connection, perhaps even a bad cable somewhere.

[M-terkait]

Originally Posted by Billfitz

The alternator should either work or not. A loose wire between the alternator and the battery would explain the heat and the low battery voltage. I don't know how the wiring runs, but since the alternator and the charging post are both under the hood it makes sense that the alternator wiring connects to the charging post, which then connects to the battery. That would seem born out by the heat there. With the car running measure the voltage at the alternator, at the post and at the battery. They should all be the same, roughly 13v. If not there's a bad connection, perhaps even a bad cable somewhere.

I took it to the indy and he told me a loose nut on the jumping post/terminal would cause this, so we just cleaned up the post and put a new wire in and it worked fine.

[M-terkait]

Im still getting low battery after 3-4days undriven, yet it starts like new car. and the voltage read by dashboard Ubatt = 14.8 at idle, went to 15.0-15.2 while driving (~2k rpm)

[Billfitz]

What does the voltage read after sitting a few days before you start it? What you read when the engine is running is the alternator output. If the battery voltage drops to lower than 12v before you start the car the battery needs to be replaced.

[M-terkait]

Originally Posted by Billfitz

What does the voltage read after sitting a few days before you start it? What you read when the engine is running is the alternator output. If the battery voltage drops to lower than 12v before you start the car the battery needs to be replaced.

I remember it was around 12.6-12.8 which is supposed to be ideal.
will try to pop the secret menu again tomorrow morning before firing it.