Battery charging C172

Due to a prolonged period of non use the 24V battery went flat on my
C172N. Is there any way a charger can be connected through the
external power point rather than the hassle of removing cowls to
connect battery charger alligator clips. It could be handy to connect
a trickle charger ocassionaly during long periods of non use? Arthur

It could be handy to connect
a trickle charger ocassionaly during long periods of non use

I don't mean to hijack your thread; I think this is relative.
Talk about a coincidence! I also have a November model. When I plug
in the yellow "jumper" tool, the gyros spool up as though the master
is turned on. I would attach alligators from the charger to the
external power point, through the yellow "jumper" tool, but i don't
want to leave the gyros spinning for hours while the battery charges.
How can I charge the battery without the gyros spinning? (with the
cowl on) Maybe someone here knows both answers. TIA

rowntree wrote:
Due to a prolonged period of non use the 24V battery went flat on my
C172N. Is there any way a charger can be connected through the
external power point rather than the hassle of removing cowls to
connect battery charger alligator clips. It could be handy to connect
a trickle charger ocassionaly during long periods of non use? Arthur

Not positive about the 172N, but most external power plugs are designed to
deliver current to the starter, not the battery. I've seen a few different
designs. With some you need to leave the master off to start, some you don't.
One thing they did have in common is that they typically bypassed the battery,
making the connection unsuitable for battery charging. There should be a
schematic for the external power plug in the flight manual. You should have
a look.

John Galban=====N4BQ (PA28-180)

--
Message posted via AviationKB.com
http://www.aviationkb.com/Uwe/Forums...ation/200801/1

If you have a cigarette lighter, the hole left after its removal just
exactly fits a 2.1mm power jack such as the Mouser #163-4302 or the Jameco
#151590. The mating power plugs are in the same general area of the
catalog. The mated pair costs about $2. "hobby shack" used to carry them;
I'm not sure if they still do.

Wire the power jack to the clock circuit. The clock uses a fuse/breaker
directly off the battery and does not go through the gyros, master switch,
or any of that. However, you have to limit the current of the trickle
charger to less than that fuse/breaker or it will trip it instantly.

Jim

--
"If you think you can, or think you can't, you're right."
--Henry Ford

"rowntree" wrote in message
...
Due to a prolonged period of non use the 24V battery went flat on my
C172N. Is there any way a charger can be connected through the
external power point rather than the hassle of removing cowls to
connect battery charger alligator clips. It could be handy to connect
a trickle charger ocassionaly during long periods of non use? Arthur
163-4302

One potential problem in this set up is if the orginal
Cessna clock circuit has be modified.

On my 172, someone in the past rewired the clock
to be on the switched side of the master contactor.
I'm guessing it was to prevent the clock from running
down the battery during long periods of non-use.

You can tell by the fact that the clock stops when the
master switch is turned off.

Anyway, I left the clock wiring like it was and simply
added a fused lead with 3 prong "tailer light" type connector
to the battery terminals. The connector was mounted with
a couple of large tie-wraps to the external power connector
housing. Now, just open the aux power door, and plug in the
float charger.


"RST Engineering" wrote in message
...
If you have a cigarette lighter, the hole left after its removal just
exactly fits a 2.1mm power jack such as the Mouser #163-4302 or the Jameco
#151590. The mating power plugs are in the same general area of the
catalog. The mated pair costs about $2. "hobby shack" used to carry
them; I'm not sure if they still do.

Wire the power jack to the clock circuit. The clock uses a fuse/breaker
directly off the battery and does not go through the gyros, master switch,
or any of that. However, you have to limit the current of the trickle
charger to less than that fuse/breaker or it will trip it instantly.

Jim

--
"If you think you can, or think you can't, you're right."
--Henry Ford

"rowntree" wrote in message
...
Due to a prolonged period of non use the 24V battery went flat on my
C172N. Is there any way a charger can be connected through the
external power point rather than the hassle of removing cowls to
connect battery charger alligator clips. It could be handy to connect
a trickle charger ocassionaly during long periods of non use? Arthur
163-4302

Thanks, Jim. I have been looking for something like this, though for a
different purpose. I hate the cigarette lighter outlet but I need it
for portable GPS power. If you so much as sneeze on the current setup
it may break the connection and interrupt the power. It's also butt ugly.

It does bring up a couple of questions for me.

1) How can I find out how much power the Jameco 151590 can handle. I
can't find anything in the POH that tells me how big of a circuit
breaker the cig. lighter is on, but I assume it's a whopper. (I
actually have the old cig. lighter somewhere and it looks like you could
light a cigar with it.)

2) Especially if I don't have to rewire to another (lower amperage)
breaker, this would be a trivial change, right? Nothing more than a
logbook entry from a cooperative A&E?

Tom


RST Engineering wrote:
If you have a cigarette lighter, the hole left after its removal just
exactly fits a 2.1mm power jack such as the Mouser #163-4302 or the Jameco
#151590. The mating power plugs are in the same general area of the
catalog. The mated pair costs about $2. "hobby shack" used to carry them;
I'm not sure if they still do.

Wire the power jack to the clock circuit. The clock uses a fuse/breaker
directly off the battery and does not go through the gyros, master switch,
or any of that. However, you have to limit the current of the trickle
charger to less than that fuse/breaker or it will trip it instantly.

Jim

--
"If you think you can, or think you can't, you're right."
--Henry Ford

"T. McQuinn" wrote in message
...
Thanks, Jim. I have been looking for something like this, though for a
different purpose. I hate the cigarette lighter outlet but I need it for
portable GPS power. If you so much as sneeze on the current setup it may
break the connection and interrupt the power. It's also butt ugly.

No you don't need the ciggie lighter jack in the airplane. Two ways of
proceeding. One, the sanitary way, cut the ciggie plug off and rewire it to
a nice small 2.1mm plug. Two, get yourself a ciggie jack and make a patch
cord from your gps ciggie plug to a 2.1mm plug.



It does bring up a couple of questions for me.

1) How can I find out how much power the Jameco 151590 can handle. I
can't find anything in the POH that tells me how big of a circuit breaker
the cig. lighter is on, but I assume it's a whopper. (I actually have the
old cig. lighter somewhere and it looks like you could light a cigar with
it.)

Jameco is notoriously short on specifications in their catalog. Mouser,
however, has the manufacturer's data sheet showing the connector to be rated
at half an amp at 12/24 volts. The keep-alive breaker (clock, radio memory,
etc.) can be up to 5 amps by regulation, and most of us throttle it back
down to an amp or two with a smaller breaker. My suspicion is that little
connector could stand a couple of amps in short circuit mode until the
breaker popped in fault mode. I'd NEVER use the same circuit that the old
ciggie lighter used for a couple of reasons. One, it isn't direct to the
battery so you could never use it for trickle charging. Two, who needs 15
amps of aux power unless you are trying to run a ham rig with lots of
transmit power.



2) Especially if I don't have to rewire to another (lower amperage)
breaker, this would be a trivial change, right? Nothing more than a
logbook entry from a cooperative A&E?

Even IF you rewire it to another breaker, it is a minor (logbook)
modification by my standards. BTW, FAA policy is clear on this. It is the
INSTALLING A&P's decision as to whether a modification is major (337 & field
approval) or minor (logbook entry). Clearly, hanging an O-470 on a C-150 is
a major mod. Wiring a small circuit breaker by THIS A&P's decision is not.

Jim

Jim

Not sure what's up here but Thunderbird refuses to let me quote Jim's
reply normally................

Thanks, the 'sanitary' way (remove the cig. lighter and replace with
something decent) is what I have in mind. The parts shipped from Jameco
today so now I need to find out if my friendly A&P will really let me do
some of the work. I guarantee you he's too busy to do it himself. My
situation here is a nightmare as far as maintenance goes. To even get
on the grounds of my county airport you have to pass signs that tell you
nobody from the outside is allowed to do work on planes there without
their express permission. But I know a guy ten minutes away who might
be willing to work with me for a reasonable fee.

I haven't been to the plane yet but I imagine I have the typical circuit
breakers. Maybe the new connector could just be wired to an in-line
fuse and connected to the existing cig. lighter wiring. But that will
be up to what the guy signing off on the job wants to see!

Tom

T. McQuinn wrote:
Not sure what's up here but Thunderbird refuses to let me quote Jim's
reply normally................

Thanks, the 'sanitary' way (remove the cig. lighter and replace with
something decent) is what I have in mind. The parts shipped from Jameco
today so now I need to find out if my friendly A&P will really let me do
some of the work. I guarantee you he's too busy to do it himself. My
situation here is a nightmare as far as maintenance goes. To even get
on the grounds of my county airport you have to pass signs that tell you
nobody from the outside is allowed to do work on planes there without
their express permission. But I know a guy ten minutes away who might
be willing to work with me for a reasonable fee.

That's not legal. Tell them to pound salt.

Just go to Radio Shack and get a cig lighter socket from them. Have the
mechanic mount it under the panel on copilots side. I've had one for
years and I have a 3-1 splitter plugged in also. Right now I have the
GPS and satellite radio plugged in.




T. McQuinn wrote:

Thanks, Jim. I have been looking for something like this, though for a
different purpose. I hate the cigarette lighter outlet but I need it
for portable GPS power. If you so much as sneeze on the current setup
it may break the connection and interrupt the power. It's also butt ugly.

It does bring up a couple of questions for me.

1) How can I find out how much power the Jameco 151590 can handle. I
can't find anything in the POH that tells me how big of a circuit
breaker the cig. lighter is on, but I assume it's a whopper. (I
actually have the old cig. lighter somewhere and it looks like you could
light a cigar with it.)

2) Especially if I don't have to rewire to another (lower amperage)
breaker, this would be a trivial change, right? Nothing more than a
logbook entry from a cooperative A&E?

Tom


RST Engineering wrote:

If you have a cigarette lighter, the hole left after its removal just
exactly fits a 2.1mm power jack such as the Mouser #163-4302 or the
Jameco #151590. The mating power plugs are in the same general area
of the catalog. The mated pair costs about $2. "hobby shack" used to
carry them; I'm not sure if they still do.

Wire the power jack to the clock circuit. The clock uses a
fuse/breaker directly off the battery and does not go through the
gyros, master switch, or any of that. However, you have to limit the
current of the trickle charger to less than that fuse/breaker or it
will trip it instantly.

Jim