Battery Replacement and Cold Cranking Amps

I have a Gill G25 battery in my Piper Arrow III (PA28R-201T). I
recently had a situation where I ran out of juice after 4 attempted
starts. While I am sure that I can improve my starting technique (I am
a newbie for this particular plane), I would like to have a bit more
power in my battery, especially in very cold conditions such as we have
up here in central Wisconsin.

An A&P told me recently that I am "stuck" with my G25 battery. He said
that he tested it and that it was "fine."

Based on a recent article in "Aviation Consumer", I learned that the G25
has only about 225 cold cranking amps. I noted that the G35S has 250
cold cranking amps.

(1) Is it true that I am stuck with a G25 battery and that NO OTHER
battery in the world can go in my plane? I find that a little hard to
believe.

(2) If there are other possibilities, can someone recommend one that has
better cold cranking amps that the G25?

Thanks in advance.

-Sami (N2057M, Piper Turbo Arrow III owner)

"O. Sami Saydjari" <ssaydjari@m> wrote in message news:101c0n2hqknsb7c@corp.supernews.com...
> I have a Gill G25 battery in my Piper Arrow III (PA28R-201T). I
> recently had a situation where I ran out of juice after 4 attempted
> starts.

The other thing you may wish to look at is the cable between the
battery and the engine. I believe that a lot of the Cherokee's benefit
from having this replaced.

Of course, your other option is to get an APU cable for your plane.
Used to help the Saratoga in the next tie down start his plane on
cold mornings.

> 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

>
> The other thing you may wish to look at is the cable between the
> battery and the engine. I believe that a lot of the Cherokee's benefit
> from having this replaced.

That is done, but good thought!

>
> Of course, your other option is to get an APU cable for your plane.
> Used to help the Saratoga in the next tie down start his plane on
> cold mornings.

I was hoping to avoid parasitism :)

>The most critical (and perhaps
>counter-intuitive) thing to remember is that the mixture needs to be in full
>LEAN (i.e. cutoff) position while cranking. You need to keep your right
>hand on the mixture while you turn the key with your left hand so that you
>can quickly move the mixture to full rich as soon as the engine begins to
>fire.

Over the years, a lot of people have recommended this procedure (mostly
CFIs), but no one has explained to my satisfaction WHY this would work.
Why are you leaning the mixture at exactly the time an extra-rich
mixture is needed? After all, that is why we prime and crank with the
throttle mostly closed. I have come to believe it is one of those old
wives tails that CFIs propagate to make it appear to students that they
are "fixing" a bad start.

Since I have been working on my instrument rating through the fall and
winter, I have been doing a lot more cold weather (well, California
cold) starts than I have in past years. My starts improved immensely after
I started doing one thing: after priming about 150% of my usual
warm-weather cold-start procedure, WAIT for 30-60 sec. before cranking.
This gives the primer fuel time to evaporate in the cylinders and form a
combustible mixture. Works every time, with no pumping of the mixture
control.


Ross Oliver

> Over the years, a lot of people have recommended this procedure (mostly
> CFIs), but no one has explained to my satisfaction WHY this would work.
> Why are you leaning the mixture at exactly the time an extra-rich
> mixture is needed? After all, that is why we prime and crank with the
> throttle mostly closed. I have come to believe it is one of those old
> wives tails that CFIs propagate to make it appear to students that they
> are "fixing" a bad start.
>

Well, (1) it's what my POH says to do, and (2) it seems to work.

Remove SHIRT to reply directly.

Dave

> Over the years, a lot of people have recommended this procedure (mostly
> CFIs), but no one has explained to my satisfaction WHY this would work.
> Why are you leaning the mixture at exactly the time an extra-rich
> mixture is needed? After all, that is why we prime and crank with the
> throttle mostly closed. I have come to believe it is one of those old
> wives tails that CFIs propagate to make it appear to students that they
> are "fixing" a bad start.

Mainly because if the electric boost pump is running and the mixture
control is in any position other than idle cut-off fuel is being
sprayed into the engine through the injection system.

You want to add slightly more than enuff fuel to get the engine
started, then shut off the flow of fuel (mixure to ICO), it'll lean
slightly when cranking (and after starting, with the mixture back, no
more is being added), reach the proper ratio to start-and-run, then
shove the mixture ahead to add metered fuel to keep it running.

No OWT's-just the operating parameters/limitations of "modern"
continuous-flow fuel injection.

TC

Here is an update on the battery saga. I had a different A&P do a
capacity test. He advised me that my battery fell below some reaonsable
threshold voltage within seconds. Time for a new battery. Arg, I am so
frustrated with the other A&P for not taking the time to do a real test.

Oh, and the previous A&P advised me that I had a Gill G25 battery. So,
I ordered a Concorde RG 25XC to get the added cranking power. Well,
unfortunately, it turns out I have a Gill G35, so they ordered the wrong
battery and it would cause a 2-3 day delay in the replacement to order
the RG-35AXC. So, now I am going with a new Gill 35.

-Sami
N2057M Piper Turno Arrow III