George,
Most of the motorcycles will still show at least 11 volts while
cranking and those are small batteries. They will jump back up to at least 12.5
after cranking. I agree that 9.5 volts is almost totally dead for practical
purposes. Most battery based systems will have trouble at around 10 volts. Use a
backup battery and a changeover system with any electrically based system. The
EXP Buss (I think) is sold by the anywhere map people. Makes it very easy to set
up a battery backup system and still charge both. I think Eggenfellner also
sells them. Good looking product, a good friend has one.
For battery info go to the Yuasa web site. In the technical
section they have a excellent do's and don'ts of battery operation. There is
also a good description of the different battery types and their discharge
rates. Good info to know about this VITAL system part!
Bill Jepson
In a message dated 2/15/2005 11:34:28 PM Pacific Standard Time,
lendich@optusnet.com.au writes:
Bill,
What would you expect the battery to show under starting
load.
George ( down under)
>
> > I suspected a
charging system failure immediately and checked the
> >battery
voltage in the SDS monitor. This read 9.5 volts so I knew then
that
>
>we had a charging system failure. At the time, I was not worried
about
> >making it to an airport, assuming that the alternator had
failed just in
the
> >last few minutes and believing that I had
20-25 minutes of battery power
> >remaining. In fact, it is likely
that the alternator failed soon after
> >takeoff from Springbank but
I did not notice signs of the failure until
the
> >battery was
well over half dead.