Alternator Charge Rate

[southsideguy]

Hello there. Would like to put out some tests results obtained using a multimeter and cigarette lighter voltage display.

Tools Used - Innova Cigarette Lighter Tester & Etepon True RMS Multimeter. Got these testers to sell also for those who interested.

Engine Off | Ignition On
Cigarette Voltage Tester - 12.6v
Multimeter on Battery - 12.6v

Engine Running
Cigarette Voltage Tester - 12.5v to 14v [Not constant but rarely goes up to 14, basically most of the time between 12 and 13]
Multimeter on Battery - In the 13, rarely goes to 14.

Question is why are the readings seldom 14? Vehicle is a Mazda 3.

[hong kong phooey]

Yes
If you want to know your charging voltage test with a multimeter at the battery.

[southsideguy]

I did. At the battery while engine running, hardly ever gets up to 14. Always in the 13.

[gastly369]

What car?

[Galvatron]

Check the condition and tension of the alternator belt, the earth strap, ensuring all connections are clean and tight and the condition of the battery.

[southsideguy]

Mazda 3. Electrician check it, he say everything normal. New brand battery.

[southsideguy]

Had to buy new battery as previous battery was suddenly dead overnight.

[maxtech]

Charging voltage for cars are normally 13.8 to 14.5....OP you alternator not charging the battery. Even if you purchase a new battery it will eventually damage that battery too. You can check you belt tension around the alternator to make sure it's tight enough.

When you change you alternator change your electrician too.

[adnj]

Charging voltage for cars are normally 13.8 to 14.5....OP you alternator not charging the battery. Even if you purchase a new battery it will eventually damage that battery too. You can check you belt tension around the alternator to make sure it's tight enough.

When you change you alternator change your electrician too.

+1. Your alternator's voltage regulation is faulty. Check the voltage at the alternator output and go from there.

[hong kong phooey]

No that sounds about right.
Did you rev the car ?
some vehicles the alternator produces about 13 V when the rpm increases then the voltage goes up to 13.8 V

[hong kong phooey]

southside guy
was it sorted ? share your findings it can be a learning experience for us

[RedVEVO]

13 good, it a range value ..

10 and under is bad

[southsideguy]

Here is my findings. I am using two pieces of tools, a voltage display on the cigarette lighter and a multimeter on the battery.

At engine off with ignition on:
[1] 12.6v on the cigarette lighter device

At engine off with ignition off:
[1] 12.6v on the battery using the multimeter

At engine running with no ac or anything else:
[1] 12.4v to 13.5v on the cigarette lighter device [it varies, does not remain constant]
[2] 13.5v at the battery terminals [constant]

[sMASH]

Start it, disconnect the battery and see what the alternator supplies on its own...

New tech giving less than 14v is suspec

[adnj]

13.5 volts at the battery terminals indicates that the voltage regulator is working below range. 12.6 volts with the engine off and the battery connected indicates that your battery is at or near (80% to 100%) full charge.

A 12 volt battery will have a 2.2 volt drop across each cell during charging (13.2 volts typical). You must overcome this potential to charge your battery. You charging system is working but not as well as it should.

Your cigar lighter outlet will likely show a different voltage than the B+ terminal voltage because of the added resistance of the wiring, fuse and terminals through the wire harness.

Increasing the electrical vehicle load may cause a voltage drop on the alternator as it sources current while at the same time the battery is at a higher voltage than the alternator and begins to dischagre.

Voltage fluctuations are likely due to electrical current draw from the ignition and control circuits, float at the negative connection to ground of the cigar lighter circuit, and possibly the design of the meter.

The only accurate way to read your battery voltage with your instrument panel meter is to wire it directly to the charge cable or the maxi fuse block of your car.

Here is my findings. I am using two pieces of tools, a voltage display on the cigarette lighter and a multimeter on the battery.

At engine off with ignition on:
[1] 12.6v on the cigarette lighter device

At engine off with ignition off:
[1] 12.6v on the battery using the multimeter

At engine running with no ac or anything else:
[1] 12.4v to 13.5v on the cigarette lighter device [it varies, does not remain constant]
[2] 13.5v at the battery terminals [constant]

[kripplerz]

Any updates with your situation. Is your batter still ok, alternator working fine ? Curious to find out.

[eitech]

Came across this link. Have a look at the comments All i have been hearing about alternators is once u start is 13-14v and anything else means something is wrong. Of course there will be the nay sayers.

https://www.quora.com/My-car-battery-vo ... alternator

[kripplerz]

There is alot more to take into account when it comes checking an alternator by just referencing the voltage by the battery terminals. All alternators now are controlled by the ecu. If the battery is fully charged there is no need for the alternator to output 14v.
Other aspects must be taken into account before you say an alternator is bad.
Internal wiring ?
Is the diodes functioning properly ?
Is the alternator outputting too much AC ?
Is the alternator receiving a proper signal from the ecu to control its output ?

[eitech]

Went by a technician in arima yesterday and he says that the newer vehicles control charging through the ecu. The signal from the ecu stops the alternator from charging. Its a problem with the tiidas as they carry 3 wire harness unlike olde model two wire systems. He eliminates that third wire and now my charging is constant

[learningcars1]

hi, i have a problem with my hatchback tiida and i am not sure if its similiar to what you had.
with a new battery, i have a no problems. but once the battery reaches 5-6 months old, i start getting 'weaker/lazier' starts, and must run the car everyday.
i have had persons check the alternator, they say its good, car charging good no parasitic drain nothing. they say bad battery and thats it. but its a recurring problem.
why are batteries getting "weaker" after 4-5 months?
eliminating the 3rd wire in the ECU helped you?

[eitech]

hi, i have a problem with my hatchback tiida and i am not sure if its similiar to what you had.
with a new battery, i have a no problems. but once the battery reaches 5-6 months old, i start getting 'weaker/lazier' starts, and must run the car everyday.
i have had persons check the alternator, they say its good, car charging good no parasitic drain nothing. they say bad battery and thats it. but its a recurring problem.
why are batteries getting "weaker" after 4-5 months?
eliminating the 3rd wire in the ECU helped you?

Yea so when i bought the car the ppl gave me a lil notebook of repair history. I observed they replaced alternator and battery a couple of times in a short space. It didnt occur to me until after two days of not starting the batter used to run down real quick. I started monitoring the charging voltage and observed it wasnt constant like in my b15. Sometimes it would be 13.5-14v, other times 12.5 volts and that while engine running. It seems as though something was turning the charge on and off. So I went to a tech and he explained what was happening. He eliminated the third wire (yellow i think, need to chk) , and i get a 13.5- 14.1 constant charging. I can leave the vehicle down for like maybe 3-4 days and it starts. The wire he cut was by the alternator connector. It,s the signal wire from the ecu. I thought i had a battery issue too but it wasnt

[learningcars1]

Sounds like my problem. Where was the tech located? Whenever i go by an electrician, they just check the poles, alternator, say it's the battery. And brush it aside. I dont know any techs that may know about this

[eitech]

Sounds like my problem. Where was the tech located? Whenever i go by an electrician, they just check the poles, alternator, say it's the battery. And brush it aside. I dont know any techs that may know about this

It’s a tech on omeara road arima just after you pass the fancy overhanging welcome sign on your left

[kripplerz]

Cutting a wire to fix a problem, what effect did that cause on the system, would it cause any further problems.

[eitech]

Cutting a wire to fix a problem, what effect did that cause on the system, would it cause any further problems.

He did say i could try replacing the brain but it wouldn’t guarantee to solve the problem. He claimed to have seen it in many of the tiidas. I haven’t had any issues since then and its almost 1 year.

[learningcars1]

Cutting a wire to fix a problem, what effect did that cause on the system, would it cause any further problems.

Do you experience a similar problem with your vehichle?