Ovation 3 Battery switch?

[ERFlyer]

Hi all!  Have just started flying an Ovation with about 20 hours under my belt.  Went to fly the other day and turned on the master with battery 1 with good voltage, the G1000 came on line, everything looked normal, then when I went to start just as I turned the key, everything went black and no power.  Switched to battery 2 and everything started fine with normal voltages and the alternator was charging normally.  I did a quick flight then after shutting down, switched to battery 1 again and no juice.  The battery had normal charge and was working fine before the sudden loss of electrics.  Any tips on things to look at before paying a local non-mooney mechanic to troubleshoot?  Thanks!

[carusoam]

Welcome aboard ERF.

Sounds like simple corrosion / oxidation getting in the way. Battery terminals and relays have been known to keep power from flowing.  But, this is not normal for any Mooney.  Expect cleaning and using everything improves their operation... check to see if the battery terminals have a contact grease on them.

You should be able to hear the relays when they click on and off.  They are next to the battery.

Don't forget to include some battery details like was it a Concorde or Gill battery?

PP ideas only, not a mechanic....

Best regards,

-a-

[Cruiser]

How old is the battery #1?

Your description sounds like the battery is low on charge. Try charging it externally. IF it takes a full charge, I would test it for capacity per Concorde's document No 5-0171 revision P

 http://www.concordebattery.com/otherpdf/5-0171.pdf

[buddy]

I had the same problem a few months ago. I switch batteries on every flight to keep them fully charged. I went to start the airplane and the prop turned about a half a blade, and my screens went blank on the G-1000's, switched batteries and the plane started fine. In flight I switched back to the dead battery and it showed the same charge as the good one so I thought it might be a bad battery solenoid. I ended up buying a new battery and that was the problem. Just a note I live in Fl. And it is amazing what heat does to a battery that I never had a problem with.

[Robert C.]

I discovered 2 months ago that batteries can just die. One of mine did, the shop charged it, wouldn't hold a charge, checked for parasitic drain, nothing. We ended up shrugging and shelling out for a new battery after deciding it probably just was an internal failure (out of warranty ofc).

[VetRepp]

How old the battery?

Same thing happened to mine,

 Battery would hold full charge and could run avionics but not enough amperage to crank the engine. I think this is not an uncommon way batteries fail.

Mine was @ 7-8 years old at the time - They have a useful life of I think 5 yrs (don't hold me to that)

I found a Battery minder helps a lot to extend life.

[LANCECASPER]

Let me guess . . It's a Gill?

[Robert C.]

mine was a Concord and was 2 years old when it dead of unexplained causes

[LANCECASPER]

58 minutes ago, Robert C. said:

mine was a Concord and was 2 years old when it dead of unexplained causes

It probably got too close to a Gill Battery 

[Jeff_S]

This is a note to Buddy, who seems to be new to the dual-battery Mooneys. It is generally recommended to NOT switch batteries in flight. While there is no prohibition against this in the POH, industry experience has shown that it can wear out the relay and cost as much as 0.5 AMUs to get it fixed. Some people say they do it all the time, others say they've learned the hard way. So you can operate as you please...I just wanted you to be aware of the opinions.

I personally do not switch in flight, after one disconcerting episode while on the ground. I was just on battery power (no engine) and was switching batteries to test something (can't even remember what) but this caused the G1000 to reset, and start poorly with all sorts of error messages. A simple cold reboot solved the problem, but I wouldn't want to be doing that in flight.  Your mileage may vary...

[PMcClure]

Is it common practice to start the engine with the avionics switch on? I prefer not to as the voltage drop may cause expensive damage. Any other thoughts?

[buddy]

Jeff, just as a note I spoke to the avionics shop on my field who is a  Garman dealer and asked him why doesn't my G1000 lose power for a split second when I switch batteries and he said the G1000 has a capacitor that holds the voltage. I wonder if that might have been your problem "bad cap".

[BradB]

1 hour ago, PMcClure said:

Is it common practice to start the engine with the avionics switch on? I prefer not to as the voltage drop may cause expensive damage. Any other thoughts?

In the G1000 planes, there is not avionics switch.  When the master is turned on, all the avionics come on.  Like you, I was used to starting planes with all avionics off.   Other pilots also notice this when they are in my plane.

 

brad

[carusoam]

The G1000 also has the engine instruments display.  To see oilP coming up during the start sequence, the G1000 needs to be on.

Best regards,

-a-

[BradB]

2 hours ago, carusoam said:

The G1000 also has the engine instruments display.  To see oilP coming up during the start sequence, the G1000 needs to be on.

Best regards,

-a-

Good point. 

[Jerry 5TJ]

I think there's several scenarios being discussed:

Jeff_S:. When you switch batteries with the engine OFF there is a momentary interruption of power.  That's GOOD as it means the batteries do not get connected together.    The power interruption is a fraction of a second, but not zero.  Your avionics buss drops to near zero and most avionics reset. 

Buddy:  When the engine IS RUNNING and one (or more) alternators are operating the momentary disconnection of batteries doesn't interrupt power.  The alternator(s) and voltage regulator keep a steady flow of current.  No avionics resets.

Yes, the G1000 power supplies do store some charge in capacitors, but not likely enough to remain operational a few hundred milliseconds: The unit uses that stored charge for an "orderly shutdown" of processors after a power failure.

PMcClure:  I think the idea voltage drop during cranking harms radios is out of date.  Modern avionics (after, say~1990) tolerate wide input voltage and transients.  Aspen and Garmin PFD are often wired to the master buss: They are on while you start.  

Long-Body electrical systems vary between models and years. All (I think) have 2 batteries. Some have one alternator, some have one  main alternator plus a standby alternator.  Some models operate two alternators in parallel.  Some have a simple "emergency buss" and a few have (nearly) full dual buss layouts.  

 

 

 

 

 

[PMcClure]

2 hours ago, Jerry 5TJ said:

I think there's several scenarios being discussed:

Jeff_S:. When you switch batteries with the engine OFF there is a momentary interruption of power.  That's GOOD as it means the batteries do not get connected together.    The power interruption is a fraction of a second, but not zero.  Your avionics buss drops to near zero and most avionics reset. 

Buddy:  When the engine IS RUNNING and one (or more) alternators are operating the momentary disconnection of batteries doesn't interrupt power.  The alternator(s) and voltage regulator keep a steady flow of current.  No avionics resets.

Yes, the G1000 power supplies do store some charge in capacitors, but not likely enough to remain operational a few hundred milliseconds: The unit uses that stored charge for an "orderly shutdown" of processors after a power failure.

PMcClure:  I think the idea voltage drop during cranking harms radios is out of date.  Modern avionics (after, say~1990) tolerate wide input voltage and transients.  Aspen and Garmin PFD are often wired to the master buss: They are on while you start.  

Long-Body electrical systems vary between models and years. All (I think) have 2 batteries. Some have one alternator, some have one  main alternator plus a standby alternator.  Some models operate two alternators in parallel.  Some have a simple "emergency buss" and a few have (nearly) full dual buss layouts.  

 

 

 

 

 

Agreed - But I don't think I will make it a habit of cranking my 2002 O2 with the 6 pak gauges and 530/430 with the avionics switch on. I have made the mistake of doing this a couple of times and notice some unusual flickering and dimming of several instruments.  Or is switching off then back on more of a risk?

[thinwing]

Back to trouble shooting problem...open left side avionics panel and with #1 battery on ,measure voltage at small terminal on battery solenoid closest to you.If no voltage,switch is not energizing solenoid and it's a faulty panel switch .More likely ,you will measure 24 v at terminal ands it's the battery relay (solenoid)No or below 24 v measurement at battery terminals ,indicates bad or dead battery.

[Jeff_S]

Jerry, thanks for that observation about the behavior of switching batteries without engine activation. It makes sense. I caused me to go back to the POH because I thought the POH included a step to switch between batteries prior to start, to choose the one that had the highest voltage. However, it actually says to switch the batteries during the "pre-takeoff" checks (aka runup) which, based on your notes, should not lead to any sort of avionics restart.

However, there is a step in the pre-start that says (paraphrased) "If Battery 1 won't start the engine, switch to Battery 2" which presumably would be done without turning off the Master.  Either way, I will continue to refrain from switching batteries in-flight, if for no other reason than "if it ain't broke, don't try to fix it at 15,000 feet!"

[carusoam]

The O1 has the check battery voltage early on, before the IP is turned on.  This indicates there are a few electronic devices up and running during the start-up procedure.  Push the button on the amp meter to guess what the voltage is.

Just not a lot of unprotected tubes in the O's electronics.  

Best regards,

-a-

[kj2016]

most likely you got a dead cell in the battery if everything else is ok. It happened to me last week. placed a new concord battery and all is well. kj

[StevenL757]

ERF,

Going back to your OP, did you get enough guidance here and have you made headway on the original problem?

Steve

[Guest]

Wouldn't it make sense to remove, charge and capacity check the battery as a first step? 

Clarence

[thinwing]

Well you are the expert..but I just went through the same thing...30 sec with a multimeter verified a bad solenoid (battery relay). Battery was fine as was panel switch...the relay is a German manufactured unit and according to Maxwell ,it has a  pretty high 1000 hr failure rate.

[thinwing]

Oh ,and it's the # 1 relay that Fails first because most pilots leave the switch in the #1 position (manual recommends alternate use)hence it is getting the most use.