Alternator current not enough

[ThushanthaSrimal]

My car is Honda city 2001 type Z

My alternator current seems to be not enough when the AC is on. I checked it with a multi meter and when the engine is in idle with AC on voltage keeps dropping in the batt terminals.

Also a sound is coming from the alternator.

Can this be a problem in the brushes?

I did a alternator coil replacement recently.

Can anyone identify the problem? What are the good places for a repair in Colombo?

[PerfMad]

4 minutes ago, ThushanthaSrimal said:

My car is Honda city 2001 type Z

My alternator current seems to be not enough when the AC is on. I checked it with a multi meter and when the engine is in idle with AC on voltage keeps dropping in the batt terminals.

Also a sound is coming from the alternator.

Can this be a problem in the brushes?

I did a alternator coil replacement recently.

Can anyone identify the problem? What are the good places for a repair in Colombo?

What's the status of your battery ? is it in good condition ? Can recommend a place around nawala, if its close by for you.

[ThushanthaSrimal]

Batt is fine. I tried with a new one also

Yes I like to know the place please

[Davy]

When you say "voltage keeps dropping", what readings do you get when AC is on and off? Something between 13.8V and 14.2V is considered normal range. Does yours drop below 13.8V?

If yes, then obviously the alternator is at fault, assuming your drive belt is not slipping.  Check the tension of your drive belt first to make sure it doesn't slip on load. If this started happening after the coil was replaced, the job may have not been done properly. Get the alternator checked (rectifier circuit especially) first. If the coil has been tampered with, you are better off buying a reconditioned alternator IMO. 

Edited April 21, 2017 by Davy
Added more information

[Rumesh88]

To check the alternator correctly, switch on all electrical loads (ie head lights and AC), rev the engine to 2000 rpm and measure the battery voltage with a digital meter. You should get a reading of not less than 13.8 volts.

[ThushanthaSrimal]

Yep it drops for around 11v

Do u have any idea about the cost it will cause me if I'm gonna change the coil

 

[PerfMad]

7 minutes ago, ThushanthaSrimal said:

Yep it drops for around 11v

Do u have any idea about the cost it will cause me if I'm gonna change the coil

 

I did the coil replacement as well (if im not mistaken) and it cost me somewhere around 7500 ~ (not exactly sure) because the part was given along with some other components as the shop owner told they won't sell only the coil. ( this is what my mechanic told)

However my issue was alternator stopped charging at all, therefore once we check for the root cause it was found out to be blown coil pack (if i recall properly) 

[Twin Turbo]

Loose alternator belt?  if belt is ok, bestvget a replacement alternator as your unit has all system components like the regulator built in.

Edited April 21, 2017 by Twin Turbo

[ThushanthaSrimal]

I repaired my alternator.

Issue was in the diode plate. One diode was not functioning. So the average voltage was too low.

Thanks everyone 

Edited April 24, 2017 by ThushanthaSrimal

[PerfMad]

2 minutes ago, ThushanthaSrimal said:

I repaired my alternator.

Issue was in the diode plate. One diode was not functioning. So the average voltage was too low.

Thanks everyone 

thanks for the update machan.. if you dont mind mention the place(contact details) and cost for the job as well  

[Davy]

The "diode plate" is the rectifier circuit that converts the alternator's AC current to DC to charge the battery. A bit surprised that the City has a rectifier with replaceable diodes since almost all new cars now have a sealed rectifier circuit which you just have to replace. Anyway, glad you got the problem sorted.