CHARGING VOLTAGE problems 740 1990 Volvo turbo

[John Robertson]

I have a Volvo 740 TURBO 1990 and recently put a Optima battery in to
replace my old worn out battery.
I seem to get only 13.7 volts when revving up and with the air-conditioner
and fan on my voltage goes right down .If I use the fan in front of the
condenser it draws so much power the car slows a bit .The voltage drops
quickly .We do get very hot weather here and I need very cool air due to
health issues .
I have just ordered an adjustable voltage regulator from IPD so I need to
know what voltage I should set it at as the whole time I have had the car it
has been lazy in charging even new brushes didn't help .
I have tightened and doubled all wiring to and from the battery and
regulator as well as earth wires clean and tight .
So I hope to up the voltage a little to what ever it needs to be ?
This car will out last me !
Thank you from down under down under .
John

[Boris Mohar]

On Thu, 2 Feb 2012 22:28:39 +1100, "John Robertson" <jon...@bigpond.com>
wrote:

Lead acid batteries have negative voltage coefficient, meaning that in hot
weather the battery voltage will be lower.



Regards,

Boris Mohar

Got Knock? - see:
Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca

void _-void-_ in the obvious place

[John Robertson]

Hot or cold the battery reads low but a slow trickle seems to lift the
battery somewhat .
There are no shorts or leaks just never up there .
One car I had shorted out on the towbar pinching a poorly installed wiring
loom for the power to the connector .
REALLY was a problem daily it would run well leave it for a week and down it
went The was flattened and split open shorting out .Any Idea what Voltage
should be when charged please?

Thanks fellow Volvo nutters





"Boris Mohar" <borism...@sympatico.ca> wrote in message
news:dbuki71nj0ihb0kr7...@4ax.com...

[Reed]

On 2/2/12 6:30 PM, John Robertson wrote:
> Hot or cold the battery reads low but a slow trickle seems to lift the
> battery somewhat .
> There are no shorts or leaks just never up there .
> One car I had shorted out on the towbar pinching a poorly installed wiring
> loom for the power to the connector .
> REALLY was a problem daily it would run well leave it for a week and down it
> went The was flattened and split open shorting out .Any Idea what Voltage
> should be when charged please?
>
> Thanks fellow Volvo nutters
>

Depends on which Optima model you have

Check the charging info here for specs:
http://www.optimabatteries.com/product_support/charging.php

[cl...@snyder.on.ca]

GENERALLY 13.8 to 14.2 volts is about normal for a car charging
system. If the voltage drops at low speed it is NOT the regulator. You
have an alternator problem or a real heavy load.

[Asbjørn]

"John Robertson" <jon...@bigpond.com> wrote in message
news:zruWq.2710$%E2....@viwinnwfe01.internal.bigpond.com...

Your condenser fan slows your CAR ? How much?
Your engine and alternator may both be too weak for your electric power
needs.
There is no free energy.

Are you sure that your battery is good ? Even a new battery could be bad.
The battery voltage ought to be at least 12.4 V one hour after stopping the
engine, with nothing turned on.
With the engine running at about 2000 r/min and nothing turned on, the
voltage ought to be around 14.4 V at the battery terminals.
That is in my climate, may be a little lower for you.
A modern intelligent charging regulator would measure both battery
temperature and charging current, and regulate the voltage from 12 to 15
V.in timed periods.
The charging voltage is often (by old habit) set as low as 13.7 in many
cars, which will be too low in cold areas and/or if you have power consuming
equipment e.g. big stereos, heavy AC use, and/or use the headlamps as
running lights, e.t.c.
(These exact voltages are temperature dependent, and the preferred charging
voltage is highest at cold temperatures.)

Google is your friend, google for instance "car battery charging voltage" or
look at for instance:
http://www.landiss.com/battery.htm
and
http://www.aa1car.com/library/battery_runs_down.htm
e.t.c.

Asbjørn
Norway

[John Robertson]

Waiting for an adjustable regulator from IPD which will charge at a higher
rate that the present one ,13.7 .
It seems the setting is too low and with 132a gas in the condenser all is
working harder .R 12 was great and the system was designed for it .Thank
your ideas and it seems charging voltage is the answer .We shall see .




"Asbjørn" <asb...@frisurf.no> wrote in message
news:jghkaf$9ai$1...@dont-email.me...

[Boris Mohar]

On Sun, 5 Feb 2012 13:47:08 +1100, "John Robertson" <jon...@bigpond.com>
wrote:

>Waiting for an adjustable regulator from IPD which will charge at a higher
>rate that the present one ,13.7 .
>It seems the setting is too low and with 132a gas in the condenser all is
>working harder .R 12 was great and the system was designed for it .Thank
>your ideas and it seems charging voltage is the answer .We shall see .
>

Make sure that the belt is not slipping, especially when the alternator is
under load.

[John Robertson]

Thanks Boris I used to leave my steering pump belts just a little loose to
stop my drivers overloading the pump .I never cease to be amazed at people
holding the steering on full lock while waiting to turn...
The low voltage has always been an issue and now I need cold air so I can
breathe the air con is more important than ever .I have disconnected the
condenser fan as it draws heaps of juice .Don,t like the low charge rate so
I will up it to 14.4 hopefully that will help .

"Boris Mohar" <borism...@sympatico.ca> wrote in message

news:svnsi7h353611ue19...@4ax.com...

[cl...@snyder.on.ca]

On Sun, 5 Feb 2012 23:02:35 +1100, "John Robertson"
<jon...@bigpond.com> wrote:

>Thanks Boris I used to leave my steering pump belts just a little loose to
>stop my drivers overloading the pump .I never cease to be amazed at people
>holding the steering on full lock while waiting to turn...
>The low voltage has always been an issue and now I need cold air so I can
>breathe the air con is more important than ever .I have disconnected the
>condenser fan as it draws heaps of juice .Don,t like the low charge rate so
>I will up it to 14.4 hopefully that will help .

You don't get it. The regulator only LIMITS the charge. If it charges
enough at speed, but not at low speds/idle, a new regulator, no matter
WHAT the setting, will NOT solve your problem.

And disconnecting the condenser fan will only make the compressor draw
MORE power, because you will raise the head pressure significantly -
and eventually blow the overpressure protection plug in the AC system.
It will also greatly reduce the effectiveness and efficiency of your
AC.

Have you tried putting an AC voltmeter across your battery with the
engine running and electrical loads turned on? Start on 20 volt scale,
then if no reading crank down to 2 volt scale, You should NOT have any
reading at all. If you do, you have a bad stator or diode in the
alternator - either of which will cause the problem you describe.

[John Robertson]

I do get it ,it doesn't charge enough at speed and as the gas makes the air
con work harder it needs more juice .
The regulator is set to low and is a common issue I believe .It never fails
just leaves the battery low after rain and head lights being on as well or
slow traffic with the air on .


<cl...@snyder.on.ca> wrote in message
news:92qti7hhurjumuvl4...@4ax.com...

[Asbj�rn]

"John Robertson" <jon...@bigpond.com> wrote in message

news:CnEXq.2685$v14...@viwinnwfe02.internal.bigpond.com...

I find "bottom posting" to be the most logical choice, that is with newt
messages added at the bottom, in chronological order.
Why can't you quit mixing top and bottom posting, this has become a mess.

Well, Clare is right, in that your generator may well be to small and not
able to produce 14.4 Volts at the needed current (Amperes).
Then you need a bigger generator or you need to loose some of the power
consumers.
A bigger battery may help somewhat, and you could use a home trickle
charger........

Asbj�rn

[cl...@snyder.on.ca]

On Mon, 6 Feb 2012 10:36:17 +1100, "John Robertson"
<jon...@bigpond.com> wrote:

>I do get it ,it doesn't charge enough at speed and as the gas makes the air
>con work harder it needs more juice .
>The regulator is set to low and is a common issue I believe .It never fails
>just leaves the battery low after rain and head lights being on as well or
>slow traffic with the air on .
>

Like I said - you don't get it - if the charging voltage is low at low
speeds it is not the regulator. If it is low under load, but comes up
with o load, it is not the regulator.

Also, the gas i n the air conditioner may make the compressor work
harder, but it CAN NOT make anything draw more electrical current.

Absolutely impossible. I've worked on automotive electrical and AC
since about 1969.

[John Robertson]

Alternator charges up as revs rise but still very low as it has always been
.Now the IPD adjustable regulator has put the voltage up where it should be
and all is fine .
Thank fellow Volvo enthusiasts .
<cl...@snyder.on.ca> wrote in message
news:qc30j7d4j1o7h7qgh...@4ax.com...

[jon]

..ALL IS WELL MY PROBLEMS SOLVED an adjustable regulator fixed up my low
charge rate even the fan rans smoother THANK YOU ALL;
EX IS A HAS BEEN SPURT IS A DRIP UNDER PRESSURE .
"John Robertson" wrote in message
news:7jmYq.2923$%E2....@viwinnwfe01.internal.bigpond.com...