2001 Hyundai Coupe [email protected]

Do you have any aftermarket stereo equipment, lights or other accessories in the car?

sir,

i did not add the stereo and light are the same before, i already tight the terminal of the battery, but sometimes when i push the accelerator its charging it range 14v.

but when i release its coming down again in 11v or 12v.

thanks

it will discharge after 3 days.

The bottom line is that you are drawing too much current for the RPM the alternator is turning.

I don't know that you really answered my question about the stereo. I don't care who installed it. Does it have an aftermarket stereo or amplifier because that will draw the excessive current I'm referring to.
It shouldn't be a big problem if you don't let it idle for extended time.

sir i change the stereo and xenon headlights last two years and the car good charging, but last week it suddenly happen this, the mechanic overhaul my transmission two weeks ago.

If you can bring the RPMs up slightly and see 14v, there is nothing wrong with your charging system. Look elsewhere for your problem if there is one.

the rpm range 3 only and the battery charging its showing 14v, but again when i release after 3 to 5 minutes it will show 12v only. i go to mechanic he said need to change the alternator. but i dont believe bacause its charging when the car run.