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Battery woes

JamesMooney
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JamesMooney Community Regular

JamesMooney

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M20F with a Concorde RG35AXC. 2.5-3 year old battery. 
After 24 years of flying, I finally did the “leave the master on” goof-up. Drained the battery to dead (whatever the lowest symbol on a Chargeminder is - the very unhappy territory). 
Local shop put it on a Chargeminder for a few days, and it showed good health.

First attempt at flying it: after start, annunciator flashed Voltage and voltmeter in plane showed 12.3-12.5. 
From other threads, I suspect that’s the end of my battery. I could spend hours and $$$ chasing it - or do I just bite the bullet, accept the price of my stupidity, and buy a new battery? 
(Side note: I don’t profess to be handy at electrical things, so returning the battery to the plane was my first time doing that… but I’m pretty sure that’s hard to screw up as long as you put it back how you found it? :) )

Fly Boomer Grand Master

Fly Boomer

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24 minutes ago, FlyingCanuck said:

M20F with a Concorde RG35AXC. 2.5-3 year old battery. 
After 24 years of flying, I finally did the “leave the master on” goof-up. Drained the battery to dead (whatever the lowest symbol on a Chargeminder is - the very unhappy territory). 
Local shop put it on a Chargeminder for a few days, and it showed good health.

First attempt at flying it: after start, annunciator flashed Voltage and voltmeter in plane showed 12.3-12.5. 
From other threads, I suspect that’s the end of my battery. I could spend hours and $$$ chasing it - or do I just bite the bullet, accept the price of my stupidity, and buy a new battery? 
(Side note: I don’t profess to be handy at electrical things, so returning the battery to the plane was my first time doing that… but I’m pretty sure that’s hard to screw up as long as you put it back how you found it? :) )

Running it flat can't be good for it, but some say they have done it, and the battery recovered.  I would try to get some help from Concorde.  A year ago, I got ahold of an engineer to get some answers regarding a GPU I was putting together.  As with anything else, if you get the right person, great things can happen.

AIREMATT Community Regular

AIREMATT

Posted
Posted

Put it back on the charger for a week. It may take a while to come back to good condition after fully running down and a couple days on the charger may not be enough time to build it back up. Might save you investing in a new battery.

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EricJ Grand Master

EricJ

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Posted
46 minutes ago, FlyingCanuck said:

M20F with a Concorde RG35AXC. 2.5-3 year old battery. 
After 24 years of flying, I finally did the “leave the master on” goof-up. Drained the battery to dead (whatever the lowest symbol on a Chargeminder is - the very unhappy territory). 
Local shop put it on a Chargeminder for a few days, and it showed good health.

First attempt at flying it: after start, annunciator flashed Voltage and voltmeter in plane showed 12.3-12.5. 
From other threads, I suspect that’s the end of my battery. I could spend hours and $$$ chasing it - or do I just bite the bullet, accept the price of my stupidity, and buy a new battery? 
(Side note: I don’t profess to be handy at electrical things, so returning the battery to the plane was my first time doing that… but I’m pretty sure that’s hard to screw up as long as you put it back how you found it? :) )

The battery can be capacity tested and/or reconditioned to determine whether it was damaged by the deep discharge or not.  Often even if the battery has been damaged it may be able to be reconditioned to extend the service life.  The fact that it came back to charge voltage means that it probably has some life left in it.

PT20J Grand Master

PT20J

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How much harm is done is a function of how old the battery is, how deeply it was discharged, how long it sat discharged and at what temperature. 

Concorde has a procedure for a deep discharge recovery in its component maintenance manuals available on its website. 

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JamesMooney Community Regular

JamesMooney

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42 minutes ago, Fritz1 said:

It happens, I leave my rotating beacon switch on for that reason

It was the perfect storm of events: the week before, the bulb in my rotating beacon burnt out. On or off, I wouldn’t have told me anything. Trust me, it doubles my annoyance at myself….

N201MKTurbo Grand Master

N201MKTurbo

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It happens when something disrupts your normal operation, like people waiting for you when you land that want to help you tie down the plane and get your stuff out of the plane. It causes you to rush to get out of the plane, and you forget to turn off the master. Also being late for a meeting or appointment can do it. Maybe even needing to go really bad.

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N201MKTurbo Grand Master

N201MKTurbo

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Your low voltage may be because your alternator doesn't have enough capacity to raise the voltage enough with the discharged state of the battery. If you just let it charge for a while the low voltage light would probably go out. 

To do the the proper thing, you should charge the battery to a float voltage of 14.1 volts before you put it back in service.

Fly Boomer Grand Master

Fly Boomer

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Posted
14 hours ago, FlyingCanuck said:

M20F with a Concorde RG35AXC. 2.5-3 year old battery. 
After 24 years of flying, I finally did the “leave the master on” goof-up. Drained the battery to dead (whatever the lowest symbol on a Chargeminder is - the very unhappy territory). 
Local shop put it on a Chargeminder for a few days, and it showed good health.

First attempt at flying it: after start, annunciator flashed Voltage and voltmeter in plane showed 12.3-12.5. 
From other threads, I suspect that’s the end of my battery. I could spend hours and $$$ chasing it - or do I just bite the bullet, accept the price of my stupidity, and buy a new battery? 
(Side note: I don’t profess to be handy at electrical things, so returning the battery to the plane was my first time doing that… but I’m pretty sure that’s hard to screw up as long as you put it back how you found it? :) )

There is a button on this page that purports to show "Distributors With Stock":

https://concordebattery.com/search-by-your-aircraft/battery_detail/159
 

Also, this is the Component Maintenance Manual for RG Series batteries Skip referred to above:
https://batterymanagement.concordebattery.com/BatteryDocs/5-0171.pdf
 

 

 

Pinecone Grand Master

Pinecone

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Posted

I like the LiFePO4 idea.  But we don't need too light of a battery, as forward CG is more of an issue.

The EarthX is 1/2 the amp-hours versus AGM.  So IFR with an alternator failure,  you have half the battery life.   IMO, it would have been smarter for them to make the battery twice as heavy (still less than 11 pounds) but about the same amp-hour.

FYI, only STC for E, F, J, and K Mooneys at this time.

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vik Collaborator

vik

Posted
Posted
5 hours ago, Pinecone said:

I like the LiFePO4 idea.  But we don't need too light of a battery, as forward CG is more of an issue.

The EarthX is 1/2 the amp-hours versus AGM.  So IFR with an alternator failure,  you have half the battery life.   IMO, it would have been smarter for them to make the battery twice as heavy (still less than 11 pounds) but about the same amp-hour.

FYI, only STC for E, F, J, and K Mooneys at this time.

Well, do a test on your 2-3 year old AGM battery.  Drain 16 Ah (using a light bulb for example) and try to turn on your avionics. See what will work and what does not - you will be unpleasantly surprised. Many radios and displays will not work even at 10V. The old lead-acid batteries, even the high quality and fresh ones,  have a pretty high voltage drop as they discharge, not talking about Concorde or Gill certified batteries, which have surprisingly short life time and seem to lose capacity very fast.

On contrary, a LiFePo4 battery will keep the voltage drop to the minimum almost to the full capacity discharge, allowing you to run all needed avionics. I did the discharge test on several older (2-5 years) Concorde and Gill batteries and the results were always not as good as I hoped. So, my conclusion is no IFR without the alternator if your Concorde or Gill lead-acid battery is more than 1 year old, but you have about  1:30-2 hours with ~10-7A drain from a LiFePo4 battery, even if it is several years old.

Besides, forgetting your master switch on will be a frustrating experience, but will not damage your Li battery. Charge it with 15-20A current while making up an excuse why you are a bit late and forget the whole incident.

Putting some aft ballast is a much harder to deal with mentally. We work so hard to make the airplane lighter to increase the useful load. An ELT and a remote transponder on the shelf right behind the battery should help a bit. Maybe a small ballast put as far aft as practical is reasonable solution too as it won't take much of a useful load off. Or getting a dog companion for the rear seat ... or it is time for another child :) Many solutions. 

 

JamesMooney Community Regular

JamesMooney

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Posted (edited)

So the saga took an interesting twist

Battery was charged for five days on a Chargeminder, and then capacity tested. Feedback from two different A&Ps/two different shops was: Battery is in great health. Good! Battery went back into plane.

Now, the alternator isn't charging the battery.

Start-up is fine, but the volt meter (cigarette lighter) never gets above 12.5V. If I put any load on the plane (avionics master ON), the amp meter shows a discharge.

A&P tested the current at the alternator and it showed zero.

What's weird is that NOTHING was wrong with the charging system (VR, alternator, etc.) before the battery discharge incident that triggered all of this. 

Local shop thinks its a bad voltage regulator - we think its the 1976 original. I've asked them to check some simpler things too, such as the wiring at the Master switch (maybe old wires final bit the dust after me cycling the Master switch a few times? Fluke chance?)

Overall: I'm perplexed how an issue of a drained battery that was re-charged and re-installed, could affect the charging system forward of the firewall? Opposite ends of the plane ;)

Edited by FlyingCanuck
Kelpro999 Community Regular

Kelpro999

Posted
Posted
16 minutes ago, FlyingCanuck said:

Overall: I'm perplexed how an issue of a drained battery that was re-charged and re-installed, could affect the charging system forward of the firewall? Opposite ends of the plane ;)

 First off do you have an alt or gen? Second do you have field and output breakers?

1980Mooney Grand Master

1980Mooney

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Posted
2 hours ago, Hank said:

Hmmm . . . . I get 6-7 years from my Concordes. And yes, it's capacity checked every annual. Methinks you speak without experience.

Also I get 6 years out my dual Concordes.  No special treatment - I almost never charge them when sitting in the hangar. 

Ragsf15e Grand Master

Ragsf15e

Posted
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4 hours ago, Kelpro999 said:

Start with field voltage check w/ master “on”. At alt. And breaker, if good move to output 

Definitely check the field voltage at the alternator with master on, engine off.  Should be just less than 12v.  While you’re there, check the connections to the alternator.  Wiggle them.

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