Ovation Batteries dead

[BillC]

I accidentally erased the original post so I'll try to repost the original question.

I flew my 1997 Ovation to Florida a few weeks ago and all was well. After three weeks sitting I tried to start it today. There was no power. Switched to number 2 battery and it was still dead. Pulled both access panels and checked battery voltage. Both batteries were reading .5 volts! you read that right...point 5 volts. I thought that the batteries were independant of each other so one battery would always remain charged. I have two Concordes that are about 1 year old. I do have a Concorde Batteryminder and tried to charge one of the batteries today for about two hours. It never went into the charge mode. I was afraid to leave it on overnight unsupervised for fear of a short.

My question is:  Shouldn't one battery be protected while using the other? Is there a relay that connects both batteries that could fail and drain both batteries?

Thanks and Merry Christmas!

[PaulM]

If everything is working correctly there should have been no way to discharge both batteries.

So, 

  There is a fault in the system.

#1  battery minders won't charge a dead battery the protection circutry needs voltage to start the cycle ... You will need to get the battery back up to at least 18-20v via some other means jump/cross charge from a full battery, or a straight 24v power supply.  Dropping a battery to .5 volts has likely killed it.  (check the water levels as well with such a deep discharge.) 

So: on to failure modes. 

The 2 battery relays are wired to trigger when the panel switch is routed to ground.  the Bat1-2 switch routes the relay to the master switch and all the master does is connect to ground.  

If the wires from the relay to the Bat1-2 switch have shorted then they will always power that relay.  This could have left either/both relays active   So we check the connectivity from the relay solenoid to ground.

The always on circuits are only connected to Bat1.   There is also a pair of diodes that trickle charge the non selected battery.  If one of these diodes have failed (shorted)  then the other battery and relay could have kept the circuit alive until both batteries were discharged.

So,

  Disconnect the batteries.  get them back up to 24v and then some debugging will show if the battery relays and switches are all good.  Then we would double check the diodes. 

 

[Cruiser]

Are you sure the #2 battery was good before ? If you don't use it regularly it can discharge and you wouldn't know.

Find a good battery and connect it to one of yours (plus to plus, neg to neg) then put the BatteryMinder on both. It will charge yours.

 

[PaulM]

If you didn't expect it, the POH schematic is incorrect and incomplete:  the light/clock always on circuit isn't shown on the bat1 side of the relay and it doesn't have the trickle charge diodes shown.. the schematics in the maintenance manual are correct and show all of the parts.  (Now I'm using a M20M diagram, but these parts are the same on both platforms) 

[BillC]

Thank you so much for the info Paul and Cruiser. That's a lot for me to digest. I'm not up to troubleshooting the electrical system so it sounds like a mechanic with better skills is needed to correctly diagnose the system. I will have both batteries serviced, if they are salvagable, on Tuesday when the mechanics are back to work. Again, thanks for the replies.

Merry Christmas, Bill

 

[PaulM]

I will assume you switch batteries every flight/start, this is best so that each battery is connected directly to the charging circuit and only using the trickle on the off cycles. My normal pattern is to switch batteries during the pre-start checklist, turn on the master, start, taxi over to fuel, re-fuel and start again on the same battery (since it really hasn't had a good charge yet).   Then switch batteries at the next start.  That does a flight on a single battery and the next flight on the other. 

At some year they added fuses on the trickle charge circuit and these can be overloaded leading to the alternate battery not getting topped off.   I only noticed this when switching batteries after start and the "second" took more current than I was expecting for a battery that should have been topped off.   I wasn't reliably switching batteries at that time... 

Edited December 24, 2017 by PaulM

[BillC]

Yes, I switch Batteries Paul. I do the same as you. 

Could you tell me where the diodes are located ? I have some experience with diodes and will be able to tell if there is a bad one. 

Thanks again,

Bill

[BillC]

1 hour ago, Cruiser said:

Are you sure the #2 battery was good before ? If you don't use it regularly it can discharge and you wouldn't know.

Find a good battery and connect it to one of yours (plus to plus, neg to neg) then put the BatteryMinder on both. It will charge yours.

 

Yes Cruiser. I'm sure the #2 was good. I regularly switch batteries when starting and also keep an eye on the engine monitor.

Thanks again, Bill

[PaulM]

The diodes are between the #1 battery relay (switched side) and the hot side of each relay. 

Either individual diodes or a four diode rectifier depending on the year:

[BillC]

2 minutes ago, PaulM said:

The diodes are between the #1 battery relay (switched side) and the hot side of each relay. 

Either individual diodes or a four diode rectifier depending on the year:

Thanks again Paul. I did find the schematic in my Maintenance manual. I also found a Service Bulletin M20-275 that recommends adding 3 fuses to the charging circuit because of the possibility of a spike causing a diode to fail. I'll bring this to the attention to the mechanic on Tuesday. I'll be using American Aviation in Brooksville Florida (KBKV). They advertise as being Mooney mechanics but I haven't seen one in their hanger yet. All the info you gave me should help troubleshoot the problem.

You have an incredible knowledge of this system. Thank you for sharing it. I'll post when the problem is resolved and let you know the outcome.

[mike_elliott]

Just now, BillC said:

Thanks again Paul. I did find the schematic in my Maintenance manual. I also found a Service Bulletin M20-275 that recommends adding 3 fuses to the charging circuit because of the possibility of a spike causing a diode to fail. I'll bring this to the attention to the mechanic on Tuesday. I'll be using American Aviation in Brooksville Florida (KBKV). They advertise as being Mooney mechanics but I haven't seen one in their hanger yet. All the info you gave me should help troubleshoot the problem.

You have an incredible knowledge of this system. Thank you for sharing it. I'll post when the problem is resolved and let you know the outcome.

Bill, I have no knowledge of Americans' abilities I am just south of there at FA40. I know Arnold Holmes in Leesburg is very familiar with Mooney's however as is Jeff Bender in Clearwater.

[BillC]

2 hours ago, mike_elliott said:

Bill, I have no knowledge of Americans' abilities I am just south of there at FA40. I know Arnold Holmes in Leesburg is very familiar with Mooney's however as is Jeff Bender in Clearwater.

I just looked up Arnold in Leesburg. He's only 40 miles from me. He would be a great choice. I'll need to get the batteries charged or replaced before I could get it to him. 

Thanks for the info Mike.

[Hank]

2 hours ago, BillC said:

I just looked up Arnold in Leesburg. He's only 40 miles from me. He would be a great choice. I'll need to get the batteries charged or replaced before I could get it to him.

See if he can come to your plane. It's a short flight.

[LANCECASPER]

3 hours ago, BillC said:

I just looked up Arnold in Leesburg. He's only 40 miles from me. He would be a great choice. I'll need to get the batteries charged or replaced before I could get it to him. 

Thanks for the info Mike.

If there's a Northern Tool open today around you this might be worth it to charge those batteries up

https://www.northerntool.com/shop/tools/product_200331941_200331941

[jetdriven]

Those batteries are likely ruined. But to do such a charge I would remove them from the aircraft and charge slowly to as high as they’ll go then put a battery minder on them and desilfate them for a long time, two weeks or more. Then capacity test per the MFR instructions and if they pass, reinstall. Perhaps for now buy one new one and then do rhe above procedure on the other two, then reinstall the best one as #2 if it passes. 

[PaulM]

17 hours ago, LANCECASPER said:

If there's a Northern Tool open today around you this might be worth it to charge those batteries up

https://www.northerntool.com/shop/tools/product_200331941_200331941

In my experience all of those  battery systems have start protection (polarity reversal) , so if the battery is very low they won't detect enough voltage to clear the protection and go into charge mode.    This is where having a second battery, or a straight 24v supply will allow you to get the system into charge mode, and then you want a slow charge to attempt to bring the battery back

[BillC]

What do you consider a 'slow ' charge. The charger at Northern Tool charges at 30 amps for 24V setting. Is that too much for these batteries? 

Update: I got both batteries out and just checked them at home. They have recovered somewhat and now show 6.7 volts each. Should this give me a glimmer of hope that they can be salvaged? 

[Mr Bill]

Bill C,

The Concorde recommended charger is the Battery Minder 244CEC1-AA-S5.  It is a 24 volt 4 amp charger. The Concorde owners manual and maintenance manual (CMM) are on the Concorde site. The Battery minder site has lots of info also. They also have a bulletin not to use Battery Tender.

So , in answer to your question, they recommend a slow charge to bring back discharged batteries, but read the Owners manual and judge for yourself. Good luck, I hope you can save those batteries, knowing what they cost.

Mr Bill

[mike_elliott]

17 hours ago, BillC said:

What do you consider a 'slow ' charge. The charger at Northern Tool charges at 30 amps for 24V setting. Is that too much for these batteries? 

Update: I got both batteries out and just checked them at home. They have recovered somewhat and now show 6.7 volts each. Should this give me a glimmer of hope that they can be salvaged? 

Hi Bill,

I have a couple of good Gill's in my hangar if you need to borrow one or 2 to get  your plane somewhere. I plan to make an APU out of them someday. (I keep them on a S2 battery minder)

[BillC]

50 minutes ago, mike_elliott said:

Hi Bill,

I have a couple of good Gill's in my hangar if you need to borrow one or 2 to get  your plane somewhere. I plan to make an APU out of them someday. (I keep them on a S2 battery minder)

Thank you for the offer Mike. I just bit the bullet and called American Aviation in KBKV. They think they may be able to save the Concordes because they are now showing 6.7 volts each. Keeping my fingers crossed. Also, I called Arnold in Leesburg and, although he would love to help me, he is about 2 weeks out with all the work he has. I'll keep you posted with the progress as soon as I hear.

Thanks again for the offer. Once I'm up and running I'd like to meet you and buy you lunch.

[PaulM]

17 hours ago, BillC said:

What do you consider a 'slow ' charge. The charger at Northern Tool charges at 30 amps for 24V setting. Is that too much for these batteries? 

Slow is what a battery minder will do.. say 4A or less.   If they have recovered, then you can give it a shot.. you can't ruin the battery any further.  If that 6.x volts isn't enough to kick the minder into charge you just need to "help" it up into the charge range.  A pair of 12V in series will give you 24 long enough to start the charge cycle. 

Remember even if we get the batteries back there is some sort of issue in the plane... 

[BillC]

Just now, PaulM said:

Slow is what a battery minder will do.. say 4A or less.   If they have recovered, then you can give it a shot.. you can't ruin the battery any further.  If that 6.x volts isn't enough to kick the minder into charge you just need to "help" it up into the charge range.  A pair of 12V in series will give you 24 long enough to start the charge cycle. 

Remember even if we get the batteries back there is some sort of issue in the plane... 

Thanks Paul. I tried to charge the batteries with my BatteryMINDer and it wouldn't charge even though they now show 6.7 volts. I'm in a new home and don't have access to extra 12 or 24 batteries so I got the mechanic at my airport to charge them and troubleshoot the problem this morning. He thinks he may be able to save the batteries. I relayed the info you gave me and also mentioned the SB M20-275 for the addition of fuses to preclude the possibility of a spike wiping out the diode(s). 

Thanks so much for all the info. I'm sure it will help in diagnosing the problem. I'll post when the problem is resolved and let you know what it was.

Thanks again Paul. 

[BillC]

UPDATE:  I had the local shop charge the batteries and was able to get them back up to 24 volts. Unfortunately, they failed the capacity check coming in at 55 and 65 respectively. Looks like another pair of Concordes are in the stars. Hopefully, they can still use the batteries to troubleshoot the discharge problem. Stay tuned.....more to follow  

[DonMuncy]

Just now, BillC said:

UPDATE:  I had the local shop charge the batteries and was able to get them back up to 24 volts. Unfortunately, they failed the capacity check coming in at 55 and 65 respectively. Looks like another pair of Concordes are in the stars. Hopefully, they can still use the batteries to troubleshoot the discharge problem. Stay tuned.....more to follow  

According to Concorde (my understanding), this makes the plane unairworthy, but from a practical standpoint, they are useable for anything but hard IFR. Keep us posted.

[BillC]

2 hours ago, DonMuncy said:

According to Concorde (my understanding), this makes the plane unairworthy, but from a practical standpoint, they are useable for anything but hard IFR. Keep us posted.

Your right Don. I believe it's 80 or 85% minimum capacity check. I just returned from the airport. They are back on the charger and are up to 25.4 volts. Another capacity check after charging should tell the story. I believe after three capacity checks, if they still fall below the 80 or 85 % they are off to the recycler. Or maybe good for a GPU.  I'll keep you all in the loop. Thanks.