'74 Super battery problem

My wife's '74 has me scratching my head for awhile now. The battery
will die with no warning or reason, and when I jump start the car it works
fine for several months. I have since then replaced the battery and
alternator. Works fine and all voltage measurements are good after each
repair and jump start.
Is there some place I should look next?

carl mciver wrote:

> My wife's '74 has me scratching my head for awhile now. The battery
> will die with no warning or reason, and when I jump start the car it works
> fine for several months. I have since then replaced the battery and
> alternator. Works fine and all voltage measurements are good after each
> repair and jump start.
> Is there some place I should look next?
>

You replaced the Alt. With an internally regulated one?
Or external and you re-used the old regulator?

If it were mine, I would jury rig a voltmeter on the
back seat (or somewhere) to monitor charging voltage
all the time. Make sure that under the heaviest loads
the battery voltage stays at ~13.5V or so.

Battery charging is tricky. Most new regulators
assume the battery only needs a little topping up
after cranking. If it consistently gets heavily
discharged, the alternator may not put enough bulk
charge back in.

If it was charging right up to time of failure again,
then test for battery drain overnight. Seems unlikely
there would be an intermittent drain though.

Of course, there is the stock advice to check all cables
and connections, including the ground strap on the tranny.

Speedy Jim
http://www.nls.net/mp/volks/

.....
> If it were mine, I would jury rig a voltmeter on the
> back seat (or somewhere) to monitor charging voltage
> all the time. Make sure that under the heaviest loads
> the battery voltage stays at ~13.5V or so.
.....

How about the 6v units??
When i put on the headlights and windscreen wiper the voltage drops to about
4.5v (idle) leaving no juse left for the horn and semaphores. This is, to my
opinion, not normal... is it?

TIA
Roger

bug '59 wrote:
> ....
>
>> If it were mine, I would jury rig a voltmeter on the
>> back seat (or somewhere) to monitor charging voltage
>> all the time. Make sure that under the heaviest loads
>> the battery voltage stays at ~13.5V or so.
>
> ....
>
> How about the 6v units??
> When i put on the headlights and windscreen wiper the voltage drops to about
> 4.5v (idle) leaving no juse left for the horn and semaphores. This is, to my
> opinion, not normal... is it?
>
> TIA
> Roger
>
>
Voltage drop is a much bigger problem on 6V cars.
Every connection has to be tight and free of corrosion.
Fuses too.
On early cars the Headlight switch fed power to *evrything*
and there was often voltage drop in the switch terminals.

Best method is to actually measure the voltage at each
point along the way and find out where the major drop is
occurring. Check voltage right at the battery too (with all
accessories running) to be sure dynamo can maintain ~6.8V

Speedy Jim
http://www.nls.net/mp/volks/

Thanks, will do (in time...:-)

Roger


"Speedy Jim" > schreef in bericht
...
> Voltage drop is a much bigger problem on 6V cars.
> Every connection has to be tight and free of corrosion.
> Fuses too.
> On early cars the Headlight switch fed power to *evrything*
> and there was often voltage drop in the switch terminals.
>
> Best method is to actually measure the voltage at each
> point along the way and find out where the major drop is
> occurring. Check voltage right at the battery too (with all
> accessories running) to be sure dynamo can maintain ~6.8V
>
> Speedy Jim
> http://www.nls.net/mp/volks/

On Sun, 24 Apr 2005 15:05:30 +0200 "bug '59"
> wrote:

>> If it were mine, I would jury rig a voltmeter on the
>> back seat (or somewhere) to monitor charging voltage
>> all the time. Make sure that under the heaviest loads
>> the battery voltage stays at ~13.5V or so.

>How about the 6v units??
>When i put on the headlights and windscreen wiper the voltage drops to about
>4.5v (idle) leaving no juse left for the horn and semaphores. This is, to my
>opinion, not normal... is it?

System voltage at idle doesn't really tell you anything about the
charging system, because the generator doesn't start to put out
anything until it gets a bit above idle.

4.5V at idle means either that the battery is in poor shape, or that
you have some bad connections which are giving you a lot of voltage
drop, or your meter is out of calibration.

-
-----------------------------------------------
Jim Adney
Madison, WI 53711 USA
-----------------------------------------------

check the earthing. mine has that problem. whenever i hit the horn, it
would give me a shock! not that great but its bad enough. anyway, my
cousin's mini cooper 73 had the same problem. it was due to a faulty
immobilizer which has an awful earthing. regards, dev