Testing current draw

[Larry Newman]

All - thanks for the response so quickly.  The battery is almost 2 years old,
not an expensive one if I remember correctly.  While it was running recently, I
hooked a real voltmeter to the the charging circuit and it charged at 13.5 to
13.9 volts consistently.  Would this be a satisfactory indicator of charging
circuit health?

I was impressed with Simon's calculation.  I wish I had thought of that.  One
question, though:  I suspect that the starter will fail even with a battery not
completely flat.  I wonder what that ampere/hour value is that will not quite be
enough to start the car.

Another piece of evidence: I drove for about an hour, parked the car for about
20 minutes, and when I opened the door to start it again, a buzzer sounded off
and wouldn't quit.  Needless to say, the car wouldn't start, didn't make a
sound.  I got a boost and went on my way.  I drove for another 2 hours, to take
my wife to the Montreal airport and another 2 hours to drive home without
shutting off the engine.  When I got home, it started fine for a couple of days,
after which it died again.

Initially, I had Sears test the battery and they put a load test on it and found
no problem.  They also said they tested the charging circuit and found it to be
working fine.  Later, after it failed again, I charged it overnight and put a
voltmeter on it while I cranked it ten times with the coil wire disconnected.
After the tenth crank, the voltmeter read 11.6, which I assumed was probably
normal.

Do either of these further symptoms support any of your ideas?



Simon Allcorn wrote:

> Huw, Larry,
>
>         That (Huw's assumption that the battery / charger may not be working
> correctly) seems quite sensible, lets do some ball park figures:
>
> Current draw = 0.017 A (0.204 Watts)
>
> Assume the battery is 48Ah (I think this is about the capacity of a normal
> battery - I'm sure it won't be any less)
>
> If the battery is fully charged then it should last with a drain of 0.017A
> for:
>
> 48 / 0.017 = 2823 hours = 117 days  = 16.8 weeks !
>
> Simon
>
> > considering how low a draw that is, even if it slightly higher than has
> > been said here is appropriate, I would investigate your charging system
> > integrity as well.  Specifically, I believe the type 44 has, among its
> > many unique and aggravating traits, a splice in the main battery wire
> > under the passenger side carpet (?) which is trouble prone.  Check the
> > battery ground and alternator functions as well, of course.
> >
> > The type 44 consumes a *lot* of electricity while running, so a poor
> > conductor to the battery might result in minimal recharging, and your
> > small "off use" curent draw could be enough to flatten your battery.  Do
> > this over and over again and you shorten the battery life, as well.  How
> > old *is* the battery, anyway?
> >
> > --
> > Huw Powell
> >
> > http://www.humanspeakers.com/audi/
> >
> > http://www.humanthoughts.org/