A Different Battery Question

On Wednesday, October 16, 2019 at 5:57:18 PM UTC-7, Dan Marotta wrote:
Yes, that's good advice.Â* I was hoping to not have to remove the rear
console where the switches are located to do the troubleshooting.

Oh well, soaring season is coming to an end and wave season is not yet
in full swing.Â* I guess I'll need something to do in the interim.

On 10/16/2019 12:09 PM, wrote:
How about divide and conquer?

Get the system in the condition you saw with more volts at the battery than the clearnav. (Maybe disconnect the batt and make sure the clearnav powers down just to make sure you have what you think you have.)

Split the path in half by measuring the voltage drop between the battery + terminal and the clearnav +power in. Then the batt- to clearnav power-..


Choose which part of the path has most of the voltage drop and pick an accessable point in the middle. Measure the two halves.

Then repeat with smaller and smaller parts of the path until you have found it.



--
Dan, 5J

Losing over 2V is much more than can be explained by a high resistance connection (it would have to be multiple ohms). I think you have a bad ground connection for some reason, and the battery is finding a ground path thru another instrument. Measure the resistance to your a/c ground bus to the negative battery terminal. Do the same for the positive connection to the 12V bus.

Tom