On 7/31/2011 10:58 PM, John Derosa wrote:
Tony,

I am with Darryl on this, with your seemingly modern electronics and a new
9AH battery, you "should not be having a problem". But of course you do
apparently seem to be having an problem. I say apparently as you say your
Dittel display disappears when you transmit but it still "... gets out
OK...". This seems like a problem with your radio, not with your battery
or wiring.

So it appears. When it happened again today, I switched the 302 to the
battery voltage screen and when I was transmitting (with the blank LCD
display), the 302 was registering 11.6 volts. So, it appears that I have
a radio or wiring problem.

What is the gauge of your wiring from the battery to your instrument panel?
If you are using small gauge wiring, and drawing considerable amps when
transmitting, then the voltage can drop considerably between the battery
and your radio. I use 12ga wiring. 14ga generally works just fine.
Anything smaller and you are throwing away voltage, which we glider pilots
cannot afford. So measure the voltage of your power system at the radio
when you hit the transmit key. If the voltage drops considerably (i.e.
from 12.5VDC to 11.5VDC) then you either have a wiring/connection issue or
your battery is bad. BTW: Only use Tefzel wiring in aircraft:
http://wingsandwheels.com/tefzel_coa...kers_louds.htm.

I will be checking the wiring to the radio very closely.

Battery Testing - Testing your batteries each year is a good idea. Darryl
mentions a very nice battery tester which does a quick job of determining
good from bad. Unfortunately, it costs $150 which is a bit steep for a
once a year effort. So here is my (slow) poor man battery testing method
that should not cost more than $10-$15:
http://aviation.derosaweb.net/#batterytest

This is nice. I typically test by putting a 1 Amp load on the battery
(using a 1156 automotive light bulb). My charger is an
accumate(http://www.accumate.com/612/), which IMHO is quite good.

Thanks for the advice!

Tony, LS6-b "6N"