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