New 110 alternator only putting out 14.1 volts.

[Wetty]

Hey All.
Got a question for you electrical minded folk out there, I just replaced my alternator (again it was only about 14 months old) with a "new out of the box" 110amp job from Deerings here in Perth, the old one was always delivering around 14.2-14.7 but this new one only reads between 13.8 and 14.2. . . . . . .tried a quick search but found nothing about normal voltage, so I would like to know if this is an acceptable range for a new alternator? It also has a fairly new belt tensioner and a nissan genuine belt so I am am hoping that isn't the issue if indeed there is one.
Cheers
Andrew.

[the evil twin]

Yes, that is OK

13.8 at idle is the minimum anything below that is bad.
14.2 at high idle and above is OK

[mudski]

Yes, that is OK

13.8 at idle is the minimum anything below that is bad.
14.2 at high idle and above is OK

At what point would you say an alternator is over charging?

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[the evil twin]

At what point would you say an alternator is over charging?

Sent from my SM-P600 using Tapatalk

IMHO 14.4 from an Alternator into a Lead Acid is as much as I would like to see and 14.2 is about ideal.

Gotta remember an Alternator is the most basic charging cct out there, no temperature compensation and relies on the Battery physics alone.

[dom14]

1q

IMHO 14.4 from an Alternator into a Lead Acid is as much as I would like to see and 14.2 is about ideal.

Gotta remember an Alternator is the most basic charging cct out there, no temperature compensation .

Why does the average car alternator need temperature compensation?

Are there some smart alternators with smart regulators that controls the output from temperature readings of the alternator core or ECU controlled temperature compensation?

and relies on the Battery physics alone.

How does the alternator rely on battery physics?

Thanx

[the evil twin]

I never said an Alternator needs temp compensation... I said it doesn't have it.
That means that you can't compare Alt output voltage to Battery Charger Voltages etc and it also means that if the battery is hot a high Alt OP voltage will cook it

The current that flows from an Alt thru a Battery is the Charge acceptance rate (CAR).
The CAR is dependant on the physics of battery technology, cell capacity and State of Charge and has no relation to Alternator AH.

Rule of thumb for a standard Lead Acid vented battery at better than 50% charge is the CAR will be max 30% of the capacity IE 30 Amps
The limiting factor to current flow is the physics behind the battery
For the same battery at 80% the CAR will drop to around 15% of capacity.

If the CAR for a battery at a given point in time is, say, 30 amps it won't matter a rats whether you have a 70 AH, 90 AH or 110 AH alternator.
The battery will take the same amount of time to recharge to the same level.

[AGman]

Are there some smart alternators with smart regulators that controls the output from temperature readings of the alternator core or ECU controlled temperature compensation?

Thanx

I notice some newer cars have a temperature sensor on the battery. I think the manufacturers are actually pushing higher voltages (and therefore more charge) into their batteries now to compensate for the auto-start function. Re-starting the engine at every intersection in a congested city must be hard on a battery/charging system, so they balance on the the bleeding edge of max current & temperature to keep the battery topped up.

Its probably why Ive switched it off in my vehicle, screw the fuel economy advantages!

[dom14]

I never said an Alternator needs temp compensation... I said it doesn't have it.
That means that you can't compare Alt output voltage to Battery Charger Voltages etc and it also means that if the battery is hot a high Alt OP voltage will cook it

The current that flows from an Alt thru a Battery is the Charge acceptance rate (CAR).
The CAR is dependant on the physics of battery technology, cell capacity and State of Charge and has no relation to Alternator AH.

Rule of thumb for a standard Lead Acid vented battery at better than 50% charge is the CAR will be max 30% of the capacity IE 30 Amps
The limiting factor to current flow is the physics behind the battery
For the same battery at 80% the CAR will drop to around 15% of capacity.

If the CAR for a battery at a given point in time is, say, 30 amps it won't matter a rats whether you have a 70 AH, 90 AH or 110 AH alternator.
The battery will take the same amount of time to recharge to the same level.

I upgraded the 60A alternator to a 110A one. The original charge wire was around 30A capacity with a 30A fuse.
I added a second charge wire with a 60A fuse. So, the combined ampacity of the two wires was roughly 90A(30+60).
The battery is generally at least 80% of it's state of charge, so the second 60A wire was not much of any use for a single battery most of the time, so I thought. 60A fuse of the second wire accidentally got blown & oddly enough, the alternator warning light on the dash came on. When I checked the wires and fuses, the old 30A fuse was still going, but getting pretty hot.
What was apparently happening was the Charge Acceptance Rate(CAR) of the battery was high enough to draw significant amount of amps from the alternator, and the old 30A wire and fuse was not quite enough.

My point being, that such an alternator upgrade does matter, even when a second auxiliary battery is not there to draw the extra possible amps from the alternator. The cranker for the most part is still capable of utilizing the advantage of the upgraded alternator, provided the charge wire and fuse are also upgraded accordingly.

http://www.nissanpatrol.com.au/forum...-short-circuit

http://www.nissanpatrol.com.au/forum...or-RB30-Patrol

So, the above rule of thumb,

("Rule of thumb for a standard Lead Acid vented battery at better than 50% charge is the CAR will be max 30% of the capacity IE 30 Amps
The limiting factor to current flow is the physics behind the battery
For the same battery at 80% the CAR will drop to around 15% of capacity.")

In my case, the battery is obviously on a far better charge state than 50%.
I would say 80% or more, yet it managed to draw way above 30A from the alternator, since the upgraded alternator was very much capable of outputting closer to at least 100A(for an alternator with a rating of 110A).

[the evil twin]

If you have a standard lead acid battery that is more than 80% charged and it has "way above" 30 amps current passing thru it... the your Battery is either screwed or will be in a short space of time.

How are you measuring the current flow thru the Battery?

[dom14]

If you have a standard lead acid battery that is more than 80% charged and it has "way above" 30 amps current passing thru it

The way above "80%" is a rough estimation from the voltage reading of the battery.

... the your Battery is either screwed or will be in a short space of time.

Pretty sure the battery is good. It's cca readings are still good and cranks like hell.

How are you measuring the current flow thru the Battery?

didn't measure it. Just estimated from the 30A fuse.
I don't have an ammeter capable of measuring amps that high.