Acclaim tail cone circuit breakers

[OneAuburnFan]

Good evening all.

I was inspecting the linkage to my oxygen bottle today in the tail cone of my Acclaim and noticed a strip of breakers next to the left battery. 3 of the breakers were labeled battery and the one labeled  “1 battery” was actually tripped. I had just returned from a quick trip today and flew 5 hours yesterday with no issues.

Questions....

1. Why would there be 3 breakers for 2 batteries?

2. I’ve reset the breaker though I wasn’t having problems. Is this a bad idea since I don’t know what it serves?  

Thanks in advance. 

[carusoam]

There are a few things back there... 

Most, you would notice immediately if they were disrupted... power to and from the batteries... and their interconnects.

The one thing that is back there that doesn’t get used very much would be the ground power supply... it’s possible that somebody grounded something that shouldn’t have been...

 

Got a pic of what you are describing? This would be really helpful... 

A handful of people may know exactly what you are describing... but would know better if they saw it too...

Best regards,

-a-

[exM20K]

Trickle charger for the battery not selected.  Mine used to do the same thing.  I’m searching my memory unsuccessfully to recall how we fixed it.

will update if I can find the work order

-Dan 

[OneAuburnFan]

23 hours ago, carusoam said:

There are a few things back there... 

Most, you would notice immediately if they were disrupted... power to and from the batteries... and their interconnects.

The one thing that is back there that doesn’t get used very much would be the ground power supply... it’s possible that somebody grounded something that shouldn’t have been...

 

Got a pic of what you are describing? This would be really helpful... 

A handful of people may know exactly what you are describing... but would know better if they saw it too...

Best regards,

-a-

I swung by the hangar this afternoon and took a  picture. The port side battery is next to this on the right as the picture was taken and the strip of breakers can be seen in the middle of the wire loom. Thanks in advance for any input.

[Little Dipper]

What does the labeling say underneath the breakers?

 

[OneAuburnFan]

the labels say Battery 1, 2, 3 on the breakers in question. I’m trying to figure out why there are 3 for a 2 battery system. And potential reasons why the one labeled battery 1 would have been tripped. 

[carusoam]

When the holidays are over...

This would be a great question to post on the Mooney.com site...

Of course, if you have the MM, the wiring diagrams aren’t that hard to follow back there...

Best regards,

-a-

[Yetti]

Maybe covered in the Operators Manual.   They got better as the years went on.

[EricJ]

Is there not a schematic in the SMM?

 

[atpdave]

On 12/28/2020 at 6:49 PM, OneAuburnFan said:

I swung by the hangar this afternoon and took a  picture. The port side battery is next to this on the right as the picture was taken and the strip of breakers can be seen in the middle of the wire loom. Thanks in advance for any input.

I don't have the schematic diagram for a M20TN but those circuit breakers correspond to a bunch of 3AG fuses installed in inline fuse holders in the tailcone of my M20R.

Assuming (1) the CBs are wired in the same way as my fuses and (2) my reading of my schematic diagram is accurate:

The three 10A battery CBs are for the battery trickle charge system.  I'd guess the BATTERY 3 CB feeds the diode bridge from the aircraft main bus.  1 and 2 would feed each battery from the bridge.  I really wish I had CBs for this circuit since a blown fuse is not obvious here.  In the absence of other faults, if battery 1 were disconnected, the + cable grounded, and the master was on with battery 2 selected, the BATTERY 1 CB could trip if BATTERY 3 CB didn't beat it to it.

The 5A EMER LIGHT 1 and 2 CBs feed the EMER LIGHT relay from each battery through some diodes.

The 5A CABIN LIGHT CB feeds the cabin light circuit from battery 1 and/or the aircraft main bus.  While troubleshooting a cabin light problem in my M20R I learned that this fuse (CB) also feeds the Hobbs meter in the baggage compartment.  In my plane (early G1000) the Hobbs meter is turned on by the second set of contacts in the landing gear airspeed safety switch, so when this fuse is blown (CB tripped) and the plane is airborne, the Hobbs stops.  Reading various Hobbs entries in my maintenance logs it seems that few maintenance people who have worked on this plane know this, and probably even fewer pilots do, which is why I'm mentioning it here.  I think the baggage light timer may be the culprit with my occasional blown fuses here.

The 10A VOLT COVT CB feeds the 14V DC-DC converter (powers the accessory socket) from the aircraft main bus.  The fuse in my plane is 5A.

The 25A COND POWER CB feeds the air conditioning condenser relay from the aircraft main bus.

If any of the above is incorrect I'd appreciate a correction.  Hope this helps.

- Dave

 

Edited January 4, 2021 by atpdave
Hobbs operation clarification

[carusoam]

Great details Dave!

The O1s came with no DC to DC converter for the plug in the inst, panel...  So that thing is delivering 24V straight to anything that gets plugged into it... 

We didn’t get a cabin light timer either...  Battery #1 is a simple switch bump away from running out of juice...

Best regards,

-a-