Battery Replacement and Cold Cranking Amps

wrote:


Since you live in central Wisconsin, you know how cold can sap a battery's
charge, particularly if left idle for a few days. But when you say it "ran
out of juice after 4 attempted starts" I am wondering (a) what you mean by
no juice,

I mean that the battery would no longer turn the engine over. The
instruments were still powered.

and (b) what constitutes an "attempt."

An attempt was about 30 seconds of turning the engine over in attempt to
get it to start.

If you mean that the
battery is discharged to a point where the prop will no longer turn with the
starter, that could mean a lot of things, including a defective starter.

Hmmm, how does one determine if the starter is the problem?



Four prolonged start attempts with a very cold engine could easily drain a
very cold battery. How, if at all, do you preheat?

I pre-heated with an external forced air heater under the cowl and a
warming blanket on top of the cowl. This was done for about 2 hours in
advance of the flight.





I presume that you have studied the
start procedure shown in the manual.

Yes, I followed the procedure as descrobed in the POH, including the one
you described.


By the way, thanks so much for taking the time and energy to offer your
good advice here. I am so impressed by just how generous folks are with
their willingness to share their experience and expertise on this forum.

-Sami

On 27-Jan-2004, "O. Sami Saydjari" wrote:

But when you say it "ran out of juice after 4 attempted starts" I am
wondering (a) what you mean
by no juice,

I mean that the battery would no longer turn the engine over. The
instruments were still powered.

and (b) what constitutes an "attempt."

An attempt was about 30 seconds of turning the engine over in attempt to
get it to start.

Well, from what you say your (cold) battery is able to crank the engine for
a total of about 2 minutes before it gets run down. That doesn't sound too
bad to me. You should note, however, that cranking non-stop for 30 seconds
is way too long. You are probably over-heating your starter. Anyway, the
real problem isn't your battery but that your (preheated) engine failed to
start. Properly preheated, it SHOULD start with no difficulty. I would
strongly suspect the impulse gear in the left mag. Or you may be flooding
the engine because of improper start technique (a preheated engine needs
only a little bit of priming) or because of a mechanical problem with the
fuel injection system. After cranking unsuccessfully for a bit, try the
"flooded engine" start technique. (Electric fuel pump OFF, Throttle FULL
OPEN, mixture to IDLE CUT-OFF.)



If you mean that the battery is discharged to a point where the prop
will no longer turn with
the starter, that could mean a lot of things, including a defective
starter.


Hmmm, how does one determine if the starter is the problem?

That doesn't sound like your problem, but a starter would be suspect if it
failed to vigorously crank the engine with a freshly charged battery. Of
course, that problem could be caused by other problems such as loose
electrical connections or corroded battery terminals.


-Elliott Drucker