Altinator Charge Voltage low at 13Volts ? Or is this Normal

[Brian the Sn@il]

I have a automatic split charge relay fitted last week.
It switches when the Main battery is charging over 13.4 Volts

Problem I have with mine is the Charge is never over 13Volts ( when engine is revving)

I would expect the Altinator to be the original on the vehicle so is 11 years old.

I have two options.

Replace the Altinator hoping a new one will charge at higher volts.

Or to install a different split charge unit.


Has anyone tested their charge Volts on their Land cruiser ?

 

[Chris]

Now I get a bit hazy when it comes to all this talk of Voles and Hams. Never mind Homes and Currants. But this could be the case that your battery won't take a full charge. The change over relay isn't triggered by the alternator, it's triggered by the battery being full. Alternators run on a sort of demand basis. They only put out what is asked of them. Someone with an electrical brain could explain better, but as I say, in simple terms if the battery won't take that charge then the alternator won't be being asked to supply it.

 

[Chas]

According to the meter I've installed in my dash my alternator charges at approx 13.4v also if I use a multimeter across the battery terminals it reads the same, (the alternator has always been like this from new) but when an external charger is connected to the batteries the dash & multimeter read approx. 14.4v could this mean my alternator is slightly faulty?
As I understand it an alternator is always 12v, the stated amperage of an alternator will be the maximum it can supply, that will change according to demand (please correct me if I'm wrong here)

 

[Doodle]

Don't panic Chas. The full explanation is long and complicated, but 12v is the nominal voltage and to actually charge properly it requires about 10% more. However, too much (>14.7v) is bad.

This might explain better: http://www.madelectrical.com/electricaltech/howitworks.shtml

 

[Chas]

Don't panic Chas. The full explanation is long and complicated, but 12v is the nominal voltage and to actually charge properly it requires about 10% more. However, too much (>14.7v) is bad.

This might explain better: http://www.madelectrical.com/electricaltech/howitworks.shtml

Thanks Doodle, I'll give that a read. So 13.4 should be OK, why then does the charger read 14.4?
As I smoke and my wife has Asthma I retire to the garage and listen to the car radio while puffing, it might be a few days before the truck gets driven so the batteries get low and now and again I have to connect a charger. I was wondering if this would affect the life of the batteries (frequent external charging)
I ought to say in my previous (working) life I was an electrician, I know the principals are the same but auto electrics have always baffled me.

 

[Doodle]

The charger will charge at its ideal voltage (i.e. 14.4v). Some alternator/regulator setups seem to sit a little below this, but that's fine.

However, if your batteries are losing charge after a few days such that you have to charge them before the truck will start, then either you have a current drain somewhere in the system or your batteries are on their way out. I've left a 'cruiser parked for 4 or 5 months and it started first time.

 

[Chas]

I think I may have another problem, as sometimes I just get the 'click' of dodgy starter contacts but if I repeatedly turn the key it will eventually fire up.

 

[uHu]

I have a automatic split charge relay fitted last week.
It switches when the Main battery is charging over 13.4 Volts

Problem I have with mine is the Charge is never over 13Volts ( when engine is revving)

I would expect the Altinator to be the original on the vehicle so is 11 years old.

I have two options.

Replace the Altinator hoping a new one will charge at higher volts.

Or to install a different split charge unit.


Has anyone tested their charge Volts on their Land cruiser ?

I have 14.3 volts at 600 RPM, and also at any higher rev.
At 13.4 you have either a bad alt. or a shorted battery cell (and one thing often leads to the other).
Not unlikely to be one bad diode, if the battery is OK.

 

[Jon Wildsmith]

sounds like bad alternator. You should have 14.2v - 14.5v at startup tapering off to 13.6v - 13.8v ish when the battery has recharged. 13.4v is a normal threshold to detect engine running / alternator charge available.

 

[Brian the Sn@il]

Thanks guys, I did have a new battery fitted last month.
So I have A New main battery and a new Aux battery.
Just seems the Alt is charging at a slight lower Voltage than it should, but I expect the amps charge rate is far more important than the voltage charge ?
Ill get auto test man to check charge amps tomorrow when hes fitting a different type of split charge relay

 

[Brian the Sn@il]

A little update on this
The Auto electrician tested the charge and it was at 14volts this morning ( cold start)
Which split charge unit cutting in and charging Aux battery.
The fault maybe when the engine / altinator is very hot.

Ill check again

 

[Steve Wright]

A little update on this
The Auto electrician tested the charge and it was at 14volts this morning ( cold start)
Which split charge unit cutting in and charging Aux battery.
The fault maybe when the engine / altinator is very hot.

Ill check again

Hi Brian

A few years ago in the days of the "Lucus" type Alternators the main problem for low (or High) voltages was the Voltage Regulator ! and if it was faulty
you could just change for a higher one, as I did a couple of times, but yours could be actually faulty, as you said it was 14 volts.

Now as John said it should be more like 14.2 to 14.5 volts.

Not sure about these type of alternators nowadays if you cand get replacement voltage regs, but see if you could get a new one and it might cure you problem
in one go, and last time I bought one it was about £10 ish but also check the brushes and again these should be readily available, and only pennys.

 

[Garfieldus]

@Brian the Sn@il - How did you get on? I think I have the same problem.

 

[Brian the Sn@il]

Sorry for the delay, im in the air con trade and its mental.

All sorted (just) the Charge rate does rise to 14v a few moments after starting, and does settle down to 13.6 volts.
Only just enough to keep the solenoid in to charge the 2nd battery.
What I have found usefeull and is something I have just purchased is a Fridge with a Wireless controller which shows you the input voltage to the fridge
http://www.mps-trading.co.uk/waeco-cfx-65-fridge-freezer~73

Really pleased with the fridge and remote controller,