Failure of Battery in Mooney Ovation

[GeeBee]

1 hour ago, Schllc said:

No other piece of machinery with an alternator as simple as a riding mower, or as complicated as a 500k rolls Royce, even has a switch to turn off the alternator, much less require you to utilize such an isolation, and their systems are arguably no less complex or sensitive. There are voltage regulators, and fuses/breakers for surges, just like our planes. 

They also don't have a battery switch either. If you start a car or boat and remove or turn off the battery, you likely will incur a large repair bill. At the minimum you will damage the alternator diodes. Ask yourself why this battery switch has "AFD" Alternator Field Disconnect.

https://www.bluesea.com/products/11001/e-Series_Selector_3_Position_Battery_Switch_with_AFD

[ilovecornfields]

18 hours ago, LANCECASPER said:

It's explained in SB M20-275 but the fuses are near the batteries. More recent Mooneys use circuit breakers in the tail section instead of inline fuses.

https://www.mooney.com/wp-content/uploads/2020/12/SBM20-275.pdf

 

I run my battery minder leads to the oxygen door, but if i had FIKI I'd use that door. I like those options better than having to leave the baggage door cracked open and ending up with critters in the airplane. 

 

Possibly, but if I'm on the ground and there's no emergency, personally,  I'd rather just shut down and restart on the other battery than risk the very expensive relay. 

 

I went with the hat rack option. I didn’t like the idea of using the TKS door since it leaves a space for things to crawl in.

[pk911]

On 1/17/2022 at 4:25 PM, ilovecornfields said:

I wasn’t aware of this. So if you’re on battery #2 with the backup alternator on and you select gear or flaps down then nothing will happen? I would have assumed the gear and flaps would run off the battery.

I can tell you after failure of main and standby alternator the system is working in full if you have good batteries and the corresponding fuses pushed. I could lower the gear without problems. Thanks Concord batteries!

[pk911]

On 1/17/2022 at 5:52 PM, LANCECASPER said:

Just thinking out loud and I'm sure I'll be corrected by someone a lot more knowledgable, but if the alternator is online while cranking I'm not sure what voltage is coming into the system, how stable it is and how that affects the voltage regulator, etc. If the POH on this application is saying to just use the starter and battery during start they must be isolating the ALT for some reason from the rest of the system until things are running and more stable. Again . .  that may not be the reason but it seems reasonable to me.

and you are increasing load to the starter for you turn an active generator  with alternator on.
You only want to turn the engine to get it started

[Aerodon]

On 1/18/2022 at 10:02 AM, ilovecornfields said:

I went with the hat rack option. I didn’t like the idea of using the TKS door since it leaves a space for things to crawl in.

 

 

OK, so I know its pricey, but this seems to be  a better idea for single batteries.  No installation time, just use your Aux Power socket to charge the battery.  I take it that the 'small positive' socket is not connected and therefore won't turn the Aux Contactor and aircraft on when you plug it it.

I'm not familiar with the dual battery wiring.   Doesn't it defeat the object if you have a precisely controlled charger that could be trying to maintain two different batteries?

Aerodon

[LANCECASPER]

4 minutes ago, Aerodon said:

OK, so I know its pricey, but this seems to be  a better idea for single batteries.  No installation time, just use your Aux Power socket to charge the battery.  I take it that the 'small positive' socket is not connected and therefore won't turn the Aux Contactor and aircraft on when you plug it it.

I'm not familiar with the dual battery wiring.   Doesn't it defeat the object if you have a precisely controlled charger that could be trying to maintain two different batteries?

Aerodon

The GPU socket only goes to Battery 1 and there’s not enough amps in a battery minder to open the relay to charge.

[FloridaMan]

A BatteryMinder can restore a Concorde battery even if it seems to be unable to hold a charge. I believe @aviatoreb managed to get 12 years out of a pair of minded Concordes in his Rocket. My batteries had changed shapes, had become concave on the sides and would not hold a charge. The battery minder restored them to full capacity and their original rectangular shape. I replaced my regulator with my alternator as the regulators are sacrificial to save your avionics and the tripping of the breaker may indicate your regulator's crowbar tripped as the result of an alternator overvoltage. 

[aviatoreb]

18 minutes ago, FloridaMan said:

A BatteryMinder can restore a Concorde battery even if it seems to be unable to hold a charge. I believe @aviatoreb managed to get 12 years out of a pair of minded Concordes in his Rocket. My batteries had changed shapes, had become concave on the sides and would not hold a charge. The battery minder restored them to full capacity and their original rectangular shape. I replaced my regulator with my alternator as the regulators are sacrificial to save your avionics and the tripping of the breaker may indicate your regulator's crowbar tripped as the result of an alternator overvoltage. 

Its true - I used a battery minder all the time - a built in one I had installed - and my concords showed good health for 12 years until on the 12 year they were showing signs of getting tired so I replaced them.

[Healthpilot]

On 1/17/2022 at 9:16 AM, GeeBee said:

You are on the correct track. Every year I read about boaters who turn their battery switch off with the engine running or the output cable comes loose. The result is fried diodes. The situation is endemic enough that high end boats have a "field disconnect" on the battery switch so the alternator is turned off in the case of battery shut off.  

During engine start, you can have a battery low enough voltage it can spike the diodes. The best way to protect the alternator is to have the field off while switching the battery on or off.

https://balmar.net/wp-content/uploads/2021/11/PDS-APM-24.pdf

 

So turn the ALT switch off also when quickly switching from BAT 1 to BAT 2 correct if engine and avionics are on? 

Usually what I do is turn off the engine and ALT field and master and then if I am on BAT 1 switch to BAT 2 so I am ready for next flight.

I thought this procedure would use both batteries and charge them more evenly but from what I read in this thread this may not be necessary at all. Correct?

 

[LANCECASPER]

9 minutes ago, Healthpilot said:

I thought this procedure would use both batteries and charge them more evenly but from what I read in this thread this may not be necessary at all. Correct?

It's good to alternate starting between batteries since on the next start if that battery is weak you'll know something's wrong right away.

[GeeBee]

Here is my installation of Battery Minder

[Healthpilot]

5 minutes ago, GeeBee said:

Here is my installation of Battery Minder

 

...

By far the most elegant I have ever seen. Did you custom create the plate? If not where can we buy one?

[GeeBee]

I did it all on my own. I bought the aluminum box and modified it with an internal platform to attach the plugs, then created a frame and faceplate. Here is the back side.

[Aerodon]

9 hours ago, LANCECASPER said:

The GPU socket only goes to Battery 1 and there’s not enough amps in a battery minder to open the relay to charge.

You are correct on both accounts.   The Battery Minder to 'Aux' plug won't work, first because it it is on the wrong side of the Aux contactor (and may not have the 3rd pin connected or enough power to pull the Aux relay closed anyway), second I agree that you would not want the battery minder to be closing the relay.

I like GeeBees double plug installation, and I would buy two Batteryminders so they can both look after the  batteries independently.

Aerodon

 

 

[LANCECASPER]

Mine isn't nearly as elegant:

[ilovecornfields]

6 hours ago, LANCECASPER said:

Mine isn't nearly as elegant:

But if it sparks won’t the plane explode?

[Boilermonkey]

8 minutes ago, ilovecornfields said:

But if it sparks won’t the plane explode?

I know you said that in gest, but I would be careful when disconnecting the O2 after filling.  Some O2 escapes as the line purges.  That being said you'd need a spark...which is unlikely.

[rbp]

putting the terminals near the O2 filler seems risky!

[rbp]

I had good luck with the BatteryMinder restoring a bad battery

[Healthpilot]

14 hours ago, LANCECASPER said:

Mine isn't nearly as elegant:

Love it. Did you use this accessory to the battery? Is it ok for certified aircraft as well? https://www.batteryminders.com/ring-terminal-assembly-rta-2415

[LANCECASPER]

Just now, Healthpilot said:

Love it. Did you use this accessory to the battery? Is it ok for certified aircraft as well? https://www.batteryminders.com/ring-terminal-assembly-rta-2415

I use a similar one to that but with lower gauge (heavier) wire. It also has an inline fuse.

[carusoam]

BatteryMinder has two sets of wire types available …

Low cost or certified…

Their customer service is fun to communicate with…

Technically the different wire coatings makes the difference….

I bought the wires and planned the install then I saw how somebody had wired the plugs to the back wall…

 

Now I realize… there are good reasons for both locations…. 
 

-a-

[Dale]

Update on the electrical system issue for my Ovation 3.  Apparently, the voltage regulator is bad and Premier is ordering another one, although they are not that easy to find as Mooney does not have any and they had to go to the original company that made the voltage regulator.  As for the issue of a dead battery in flight with the main alternator left off, Premier has advised, as has Corby Hallaran, my CFI Mooney Instructor, is that the procedure should go like this:

a.  If battery 1 is dead, DO NOT switch on the main alternator.  There is apparently some type of "in rush" on the lines and it is bad for the electrical system and, I guess, can blow your voltage regulator;

b.  Switch to the good battery #2, get everything running and then turn on the main alternator.  Everything should function normally, provided there is nothing else affecting the electrical system, other than the dead battery.

On the issue of switching batteries in the air while the electrical system is operational, here is the take:

a.  Provided both batteries are good and fully charged, you can switch from battery 1 to battery 2 in the air with the master switch on and the main alternator on and operational without any injury to the electrical system, the batteries or the alternator.  Corby told me that he does this when he flies the Acclaims and the Ovations and has done this many times and there are no problems.  He also does this on test flights for Premier on the Acclaims and the Ovations as part of a general electrical system check.  This is a standard part of the electrical system check that is routinely done.  He switches the batteries in the air and checks their voltage.  Corby did so today in testing two G1000 Mooneys at Premier that had just come out of annual.  Premier mechanics concur that as long as the batteries are good, there is no problem switching from one battery to the other in the air with the alternator on and the electrical system operational.  No relays will fry.  

There is also the alternator and standby alternator test and run up procedure from the Mooney AFM Supplement, which I do when I am flying IFR, and that is

1.  with the main alternator on, set the RPM for between 1700 and 1800 RPM and verify that the Red Alt Volts annunciator light extinguishes; then

2. turn the Alt Field Switch OFF and verify that the Red alt Volts annunciator light is ON;

3.  Turn ON the Emerg Bus switch and verify that the Amber Emergency Bus annunciator light illuminates;

4.  Turn OFF the Emergency Bus Switch and verify that the Red Alt Volts annunciator light is ON

5.  Turn ON the Alt Field Switch and verify that the Red Alt Volts annunciator light extinguishes.

I am supposed to get my plane back in the next few days once Premier has completed the repairs and verified there are no other electrical system issues.  The gear checked out ok and the batteries have checked out ok and are holding a full charge.  I have arranged time with Mr. Hallaran to spend time going over, once again, the electrical system in my Ovation so I handle any electrical issues that may come up in the future and follow the correct electrical procedures.  Thanks for everyone who has responded to this post.  It is greatly appreciated.  Thank you again.

[kortopates]

On 1/20/2022 at 11:34 AM, rbp said:

I had good luck with the BatteryMinder restoring a bad battery

not at all!

 

[rbp]

If I wanted a permanent battery minder hookup, do I need the whole $70  kit? One for each battery?