Bad battery or Real Drain???

[Releew]

Had a strange problem this weekend..... Went to start the Mooney, flipped the Master and NOTHING! No click, no lights....Nothing!

I placed the Fluke meter on the Battery and is was not reading a Single Volt.... The plane had sat for three days since my partner flew her last. All switches were off and everything appeared to be normal. I placed a 5 amp charger on the battery for an hour and she started right up as usual. The Battery was drained as I saw the Alternator doing its job making voltage and current. I stayed on the ground for an extended period of time until I saw the amperage start to back down to slightly above ZERO. All systems looked fine so I flew the aircraft on a short hop. All electrical equipment was operating as designed.

I have heard a lot of Bad about Gill Batteries but in this case I think there was reason for the full discharge. My question is......Is it possible for the Relay normally activated by the Master to stay partially engaged or for the coil to stay hot? I also see a diode attached as well. Could that have created the drain?

The mooney is a 1992 M20J. Any advice would be appreciated. If anyone knows how to acquire electrical diagram it would be extremely helpful.

FYI.... This site has been very valuable. What a great group of enthusiast helping each other maintain their passion for these great airplanes. Even with minor problems, these aircraft have some of THE BEST engineering I have seen in a very long time!

Thanks, Rick

[carusoam]

Your POH should have the basic electrical diagram...?

The classic sign of a Gil being a Gil.... When it dies, it usually doesn't resurrect itself. Not even using a Gil battery charger.

Best regards,

-a-

[Piloto]

Check the overhead light switch. If left on the lights will discharge the battery even with the master off. I rewired mine to get power from the stall/gear buzzer supply line so they will be switched off when I turn the master off.

 

José 

[Jerry 5TJ]

If you suspect a 'vampire' drain on the battery even with the master switched off you could run a test while parked and on the ground:  Connect a current meter (your Fluke if it has an amps mode) in series with one of the battery leads.  (that is to day, disconnect one of the leads from the battery and insert the meter between the battery and the disconnected lead)   Test with the Master Switched OFF.   A drain of even a few tens of milliamperes that can take the battery flat in a week.   

[201er]

Check the overhead light switch. If left on the lights will discharge the battery even with the master off. I rewired mine to get power from the stall/gear buzzer supply line so they will be switched off when I turn the master off.

 

José

Then how do you light things up for your passengers getting out at night after shutdown. The system makes sense. Just don't forget to turn it off.

[DonMuncy]

Or you can put a timer in the system.

[ArtVandelay]

Then how do you light things up for your passengers getting out at night after shutdown.

Flashlight?

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[jkhirsch]

Then how do you light things up for your passengers getting out at night after shutdown. The system makes sense. Just don't forget to turn it off.

 

Park right in front of the FBO

[Piloto]

I had two events were the lights were accidentally turned on while loading the plane with large baggage and one that a curious nephew turned on. All during daytime. These lights are more suited for inflight use than for guiding someone to the foot step at night. I would rather use a flashlight than face a discharged battery on my departure.

 

José

[201er]

Good points.

[carusoam]

Or get the circuit mounted with a timer...?

And a second battery...

Or Go O!

-a-

[Danb]

Jose make a strong point this is a screwed up setup Mooney has. I've been lucky it's the last item on my shutdown checklist.

[DonMuncy]

If you put the timer in the circuit, you do not need a second battery. There is no way you can leave it on (longer than the time designed into the timer.)

[carusoam]

And use an led light....

Whelen supplies a nice simple LED for the IP.

Best regards,

-a-

[Releew]

Thanks very much everyone! It was the overhead lights….. My partner took a friend that had "wandering fingers!!!!" He flipped the rocker to Dim and the lights stayed on for 3 days. I went to the Airport this morning to quickly check the battery and did not open the main hangar door. I hit the Master and NOTHING again!!! As I backed out of the aircraft I saw a dim glow. AMAZING how something so simple was that easy to miss. Lets say I feel very inept! I knewthe circuit was direct but still failed to take a hard look at it! I did not notice it until there was low ambient light and enough charge in the battery toshow a glow!! I will put a LED facing down to make it more obvious when the switch is on.

Appreciate the replies!!

Rick

[201er]

Thank you Rick for making such a dumb mistake so that we could all learn from it

 

This will add to the ever-growing list of tidbits I've learned on this forum.

[Marauder]

Thank you Rick for making such a dumb mistake so that we could all learn from it

This will add to the ever-growing list of tidbits I've learned on this forum.

We're waiting for your list...

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[Releew]

Looks like a few others made that dumb mistake as well. That's the best attribute of this forum. It full of learning experiences...... Mistakes are regrets.... I have none!