CHARGING VOLTAGE problems 740 1990 Volvo turbo

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)

void _-void-_ in the obvious place

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:

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:

Asbjørn Norway

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.

Regards,

Boris Mohar

Got Knock? - see: Viatrack Printed Circuit Designs (among other things)

void _-void-_ in the obvious place

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.

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 .

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........

Asbjørn

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.