Plug and Jump

[NVArt]

Problem grows out of a six month old RG battery that won't hold a
charge for two weeks. Bought a plug and Jump from Aircraft Spruce.
Neato idea; I don't have to remove the cowl. I was going to use it to
trickle charge the battery. Trouble is, when I plug in the Plug and
Jump, it powers the panel. I don't want the gyros spinning for hours
while the charger is charging the battery. What's a mother to do? C172N
model.


5217D
HTH

[Mike W.]

Maybe attach some kind of quick-disconnect plug to the battery. Then you
could just open the oil door and hook it up? Something similar to a trailer
light plug on the battery and a matching plug to the charger.
I assume this thing you are talking about attaches somewhere in the interior
of the plane?

"NVArt" > wrote in message
oups.com...
> Problem grows out of a six month old RG battery that won't hold a
> charge for two weeks. Bought a plug and Jump from Aircraft Spruce.
> Neato idea; I don't have to remove the cowl. I was going to use it to
> trickle charge the battery. Trouble is, when I plug in the Plug and
> Jump, it powers the panel. I don't want the gyros spinning for hours
> while the charger is charging the battery. What's a mother to do? C172N
> model.
>
>
> 5217D
> HTH
>

[NVArt]

> I assume this thing you are talking about attaches somewhere in the
interior
> of the plane?
>
> Thanx for the quick response. The Plug and Jump installs through a
small door on the left side of the lower cowl. I would prefer to use
this access, but I may be pushed to your idea, even without field
approval. I'm trying to keep the bird as factory original as I can,
'cuz even though I don't believe Cessna is perfect, they're probably
better than my own imagineering.
> >
> >
> > 5217D
> > HTH
> >

[Steve Foley]

Pull the fuse/breaker for the gyro

"NVArt" > wrote in message
oups.com...
> Problem grows out of a six month old RG battery that won't hold a
> charge for two weeks. Bought a plug and Jump from Aircraft Spruce.
> Neato idea; I don't have to remove the cowl. I was going to use it to
> trickle charge the battery. Trouble is, when I plug in the Plug and
> Jump, it powers the panel. I don't want the gyros spinning for hours
> while the charger is charging the battery. What's a mother to do? C172N
> model.
>
>
> 5217D
> HTH
>

[Ben Jackson]

On 2005-03-26, Steve Foley > wrote:
> Pull the fuse/breaker for the gyro

Breakers aren't meant to be switches. If you use them as switches you'll
wear them out prematurely.

--
Ben Jackson
>
http://www.ben.com/

[[email protected]]

NVArt wrote:
> Problem grows out of a six month old RG battery that won't hold a
> charge for two weeks. Bought a plug and Jump from Aircraft Spruce.
> Neato idea; I don't have to remove the cowl. I was going to use it to
> trickle charge the battery. Trouble is, when I plug in the Plug and
> Jump, it powers the panel. I don't want the gyros spinning for hours
> while the charger is charging the battery. What's a mother to do?
C172N
> model.
>
>
> 5217D
> HTH

HTH...

Some bad advice so far.

Your description of the small door on the left suggests you have the
normal external power circuit. When you apply power to those big stud
it causes the battery solenoid to make and that allows power to be
applied to the battery.Any accessrry which is not switch controllable
will be energized. The feature allows external power to start the
engine, that being the reason the terminals are so large.

You did not say if you can switch off the gyros and I don't know but
suspect they are connected to the bus and cannot be disabled?? And
Cessna has long chosen the cheapest circuit breakers which are
unpullable.

Back to fundamentals. If the battery is that new/old, then there is
something draining it when the plane sits or there is something wrong
with the battery. What have you done to check the battery?

If you jury rig a connection which allows a trickle charge to the
battery and then hook a dead battery to a source which has the ability
to apply a lot of current, the jury rig will quickly fry.

Suggestion to plug a trickle charger into the cigar lighter are doomed
as well since that socket it only powered when the master is on and
you are right back to the gyros running.

Start with basics. Battery....get tested and fully charged and then
find out if you have a sneak path which is drawing current when the
plane is not running....there is often a clock circuit which is hooked
up "around" the master solenoid and it takes power constantly, though
only enought to keep the clock running.

Your POH should have a rudimentary circuit near the back.

Neal

[Vaughn]

"NVArt" > wrote in message
oups.com...
>... I was going to use it to
> trickle charge the battery.

Be aware that your normal, cheap, trickle charger will ruin your battery in
just a few months, take it from someone who has learned the hard way. They make
special trickle chargers (called "float chargers) that can be left connected
indefinitely, but they are not cheap. I use this company's products:
http://www.batterytender.com/ but there are others on the market.

Also, notice the rows of airplanes at your field that do not have trickle
chargers connected, yet always seem to start. What makes your plane different?
Why don't you just take the trouble to find the problem and get it fixed?

Vaughn

[Jim Burns]

> find out if you have a sneak path which is drawing current when the
> plane is not running....there is often a clock circuit which is hooked
> up "around" the master solenoid and it takes power constantly, though
> only enough to keep the clock running.
> Neal
>

Neal's got a good idea. We flew an Archer once that had the same symptoms.
Turned out to be the clock circuit was drawing way too much power and
draining the battery. It had an inline fuse back by the battery so all we
had to do was pull the fuse. We believed that there was a shorted wire in
the clock circuit allowing it to draw more than the clock required. The
plane was sold before they ever told me what they had found.

Jim

[tom418]

Walk up to the "P6" C/B panel on a B727 and pull the Battery Charger and
"ESS DC BUS TIE" C/Bs. These will pull out a lot easier than the others,
since they get pulled when performing a daily check of the battery charger.
"Ben Jackson" > wrote in message
...
> On 2005-03-26, Steve Foley > wrote:
> > Pull the fuse/breaker for the gyro
>
> Breakers aren't meant to be switches. If you use them as switches you'll
> wear them out prematurely.
>
> --
> Ben Jackson
> >
> http://www.ben.com/

[NVArt]

> Also, notice the rows of airplanes at your field that do not
have trickle
> chargers connected, yet always seem to start. What makes your plane
different?
> Why don't you just take the trouble to find the problem and get it
fixed?
>
> Vaughn

My ride wasn't *different* until I got the RG battery, so I *know*
where the problem is. I was just trying to find an easier temporary fix
than screwing with a return/replacement, downtime, etc. until I buy
another lead-acid battery which typically have lasted at least three
years. Am I being too lazy? (exposing my soft underbelly)I dunno. I
built a hangar with electricity so a quick plug in for an hour would
not be much of a problem. Oh, and I'm three minutes from residence to
hangar. Out in the middle of BF., Nevada. We have three planes based
here. But I get your point.
Thanx to all that responded.

5217D @HTH

[Steve Foley]

Batteries aren't meant to die after 2 weeks.

"Ben Jackson" > wrote in message
...
> On 2005-03-26, Steve Foley > wrote:
> > Pull the fuse/breaker for the gyro
>
> Breakers aren't meant to be switches. If you use them as switches you'll
> wear them out prematurely.
>
> --
> Ben Jackson
> >
> http://www.ben.com/

[nrp]

I also have a 172M (N5132H) but I get about 8 years minimum on the last
three ordinary lead acid battery - with no between flight recharges.
The clock still works too. I suspect if it ever quits, there is the
possibility that it could draw current continuously rather than as a
simple pulse. Otherwise the golden rule on batteries is to keep the
plates covered at all times - even if the water has to come freom the
tap or a mud puddle.

The battery can be recharged thru my ground service plug, but it
requires a fairly high voltage from the charger to charge the 12 V
battery. From the circuit it seems to bring the charge current thru a
series resistor and an isolating diode. It also requires the basic bus
to be energized running the rate-of-turn, in order to charge.

If you let the A/C battery become fully discharged (such as leaving the
master on) there is nothing to self energize the alternator even if you
get it started thru the ground service receptacle (sp?). Leaving the
ground service plug in place for a few minutes before attempting a
start, allows a little bit of charge to get in the A/C battery,
allowing the alternator to start. These few minutes are not going to
hurt the rate of turn. If you wanted to charge more extensively, you
could reach behind the panel and unscrew the connector on the back of
the R/T. Don't let it dangle though as it might get in the control
column travel.

Why Cessna did it this way, I don't know unless to protect the
electronics?. Does anyone else know? In general I think they had a
very good electrical system.

For that matter, do I have it right? Where is that darn charge-thru
diode and resistor? What is the value of the resistor (maybe 5 ohms?)?
The schematics I have looked at in the pilots manual and the Cessna
service manual don't seem correct, consistent, or even look complete in
that area.

nrp

[Vaughn]

"nrp" > wrote in message
oups.com...
>
>
> If you let the A/C battery become fully discharged (such as leaving the
> master on) there is nothing to self energize the alternator even if you
> get it started thru the ground service receptacle (sp?).

It happens sometimes, but recognize that running a battery until it is
discharged flat is one of the worst things you can do to it. The very worst
thing that you can do is run a battery flat and then leave it discharged for any
length of time. It is sort of like us humans after a bad heart attack. They
may bring us back to apparent health, but we will never be quite the same and
our life expectancy will, on average, be significantly reduced.

Vaughn