Dead battery

ryoung99

ryoung99

Pre-takeoff checklist
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Lees Summit, MO
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Rick
So I arrived at the Tiger @ 5:30 this morning to find a dead battery. No one around, so my day was done before it started.

The battery is a Concorde RG-25XC, installed in 2011.

What is the safest way to bring it back to life, or should I just consider it a goner?

Thank you in advance for your thoughts and advice.

Rick
 
I would first try a slow charge, with a good charger/de-sulphator. And see what happens. That battery has only 2 years on it since it was filled and installed.
 
Why is it dead? Someone leave the master on?

Dan
 
Dome light was left on, that is the only thing I could find, the master was not on.
 
It should be fine. Put it on the slow charger, about 6 amps continuous and leave it for a day. Put it back in the plane and give it a go. If you want to check the electrolyte level get a cheap Hydrometer from O'reillys and dip in each cell and read the level.
 
On the RG25XC I'd go even slower. Concorde instruction for this situation IIRC calls out a 2 amp charge rate. Trickle that thing back to life.

It will however, probably fail the 90% discharge test at annual, however. But, MAYBE NOT!
 
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If that's the case, ask the GA folks about disabling the fuse or C/B on the hot bus when it's parked. Doing so is common practice on some of the Beech products.



ryoung99 said:
Dome light was left on, that is the only thing I could find, the master was not on.
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bbchien said:
On the RG25XC I'd go even slower. Concorde instruction for this situation IIRC calls out a 2 amp charge rate. Trickle that thing back to life.

It will however, probably fail the 90% discharge test at annual, however. But, MAYBE NOT!
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That's not actually what the Concorde "Instructions for Continued Airworthiness" state.

See p. 1501, steps 6 and 7. Says to use constant potential charging at rates up to 8C1 to recharge the battery, and only to follow the conditioning charge procedure if the preferred constant potential charge procedure doesn't give good results.

May sound crazy, but that's the manufacturer's recommendation. They even say it in BOLDED ALL CAPS, so I don't think it's a typo.
 
Concorde rep I spoke with this spring stated to charge the battery with the highest current possible that will keep the battery from getting hot to the touch.
 
And yet we see folks jump start the aircraft and allow the alternator hit the battery with 60 amps while they fly away.

the ICAs address the "on the bench charge rates" not what happens in real life.
 
interesting advice, to not trickle charge the dead battery. I would have thought trickle was the best chance to revive it.
 
I just spoke to my mechanic and he told me to do about what the Concorde to said. Thanks for all the responses, the battery was real strong before this, hope it works and saves it.
 
NineThreeKilo said:
2 blade prop??

Hand flip it and get on with it.
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That's a good way to smoke the battery and alternator.

A completely dead battery needs to be coaxed back to life. With a fast charge for a few mins, then a trickle charge to top it off. Trickle charge make take a day.

An alternator is used to top off and maintain a healthy battery after starting, not fully charge a dead one. Way too hard on it.

Don't confuse a car's system with an airplane. The operating conditions are way different.
 
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Beyond that, if the battery is dead, the alternator won't even come alive.
 
Jim_R said:
That's not actually what the Concorde "Instructions for Continued Airworthiness" state.

See p. 1501, steps 6 and 7. Says to use constant potential charging at rates up to 8C1 to recharge the battery, and only to follow the conditioning charge procedure if the preferred constant potential charge procedure doesn't give good results.

May sound crazy, but that's the manufacturer's recommendation. They even say it in BOLDED ALL CAPS, so I don't think it's a typo.
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Please read the same ICA, section 9 which deals with batteries that fail the load test, which is the case with this battery. The charge rate is not the same as section for constant potential which would be used for a battery that is in service, but has been moderately discharged. The second sentence in section 8 is the key: IF THE BATTERY DOES NOT PASS THE CAPACITY TEST, THE CONDITIONING CHARGE PROCEDURE SHOULD THEN BE USED.

Also go back and read section 7 G, H. I would not recommend using 8C1 for a battery which is fully or nearly full discharged at a rate close to this. Most likely it will explode, or melt down. The conditioning rates are specified in 9 step C and D:

C. Charge at a constant current rate of C1 /10 (i.e., 4.2 Amps for a 42 Ah
battery) until the voltage on charge is 31.0 volts (15.5 volts for 12 Volt
batteries) or higher for 4 hours, then discontinue charging.

D. As an alternative to Step C, charge at a constant current rate of C1 /10 (i.e.,
4.2 Amps for a 42 Ah battery) for 16 hours, then discontinue charging.

As indicated in my prev post, put it on a charger that will provide about 6 amps and leave it overnight(basically, step D). The Schumacher 8 amp will float the voltage just right. It'll start out around 6 amps, and slowly go down as the internal battery voltage rises so that the electrolyte is not burned off.

that's why it sounded crazy, so please don't charge at 8C1 on a dead battery. The plates will surely warp, even if they don't touch and it's quite possible that the boil off can start a fire.
 
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Skylane81E said:
This battery has yet to fail a cap check
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Uhh, from the op: "So I arrived at the Tiger @ 5:30 this morning to find a dead battery."

I'm going to go out on a limb and say this battery will not pass a capacity check. I know it's a risk to say, but it's one I'm willing to stake my rep on.
 
Given that the battery is the electrical redundancy for my alternator, I have decided that $250 is not worth my life or the lives of my passengers which include my 3 year old.

When I pull the old battery out we will see if we can bring it back to life, and use it as a short term back up, but in the end, I will just chalk this up to a life lesson and make sure all the switches are off before putting the plane away in the future (seems like a reasonable thing to do anyways).

Thanks,
Rick
 
Generally not a bad plan, but many people don't consider the potential for infant mortality(batteries, as it were). If you have a battery that in all other respects was functioning well, and it went through one slow discharge cycle in 2 years of ownership, I'd say your risks are about equal with the one you have, vs the one you buy. I know I've bought a batt for my wife's Mini that had an intermittent open in one of the cells. It took three trips back to the place we bought it before they would exchange it for new.
 
Geico266 said:
If you have to ask you wouldn't understand. ;)
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I guess,,,, Shape and size do make them different.

A lead acid battery is a lead acid battery no matter how they are used.

An Alternator is an alternator no matter how it is used.
 
docmirror said:
Uhh, from the op: "So I arrived at the Tiger @ 5:30 this morning to find a dead battery."

I'm going to go out on a limb and say this battery will not pass a capacity check. I know it's a risk to say, but it's one I'm willing to stake my rep on.
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Cap check is tipically done on a charged battery, we are interested in its ability to hold a charge, not its charge state.
 
Skylane81E said:
Cap check is tipically done on a charged battery, we are interested in its ability to hold a charge, not its charge state.
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Let me help you out with this. A battery with an output voltage of zero, or near zero has no ability to hold a charge. Once the battery is recharged using section 9 info, or if you prefer you can go all the way back to section 3 where the tests are done will put you in the ballpark where a capacity check can be performed.

And I'm done here.
 
docmirror said:
Let me help you out with this. A battery with an output voltage of zero, or near zero has no ability to hold a charge. Once the battery is recharged using section 9 info, or if you prefer you can go all the way back to section 3 where the tests are done will put you in the ballpark where a capacity check can be performed.

And I'm done here.
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Very, very very seldom does the voltage actually get drawn that low. It is possible in this case, but not certain.

I would charge the battery, cap check it and go from there. I have found I can usually save a battery once
 
docmirror said:
Let me help you out with this. A battery with an output voltage of zero, or near zero has no ability to hold a charge. Once the battery is recharged using section 9 info, or if you prefer you can go all the way back to section 3 where the tests are done will put you in the ballpark where a capacity check can be performed.

And I'm done here.
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You may be done here, but your interpretation is NOT actually what the manufacturer's procedures say to do.

The procedures say, do a capacity test before performing a conditioning charge. There is no exception for "unless the battery has been deeply discharged".

The first step in the capacity test is to charge the battery using the preferred charge method--constant potential. The procedure also says, in bold black letters, to charge at the highest rate possible, up to 8C1. (Note that the capacity test is NOT intended to take a battery at an arbitrary state of charge and see if it will support a test load, like you seem to think. It's intended to take a battery at an arbitrary state of charge, completely charge said battery from whatever level it started at, and THEN see if it will meet the load test criteria.)

If, and ONLY if, after fully charging the battery using the preferred charge method, the battery fails to meet the test criteria of the capacity test, THEN use the conditioning charge procedure.

You may choose not to follow the manufacturer's procedures, but that's what they say to do.
 
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Jim_R said:
That's not actually what the Concorde "Instructions for Continued Airworthiness" state.

See p. 1501, steps 6 and 7. Says to use constant potential charging at rates up to 8C1 to recharge the battery, and only to follow the conditioning charge procedure if the preferred constant potential charge procedure doesn't give good results.

May sound crazy, but that's the manufacturer's recommendation. They even say it in BOLDED ALL CAPS, so I don't think it's a typo.
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Thanks for not penalizing me for being lazy! If forgot about constant potential charging.....
 
Jim_R said:
You may be done here, but your interpretation is NOT actually what the manufacturer's procedures say to do.

The procedures say, do a capacity test before performing a conditioning charge. There is no exception for "unless the battery has been deeply discharged".

The first step in the capacity test is to charge the battery using the preferred charge method--constant potential. The procedure also says, in bold black letters, to charge at the highest rate possible, up to 8C1. (Note that the capacity test is NOT intended to take a battery at an arbitrary state of charge and see if it will support a test load, like you seem to think. It's intended to take a battery at an arbitrary state of charge, completely charge said battery from whatever level it started at, and THEN see if it will meet the load test criteria.)

If, and ONLY if, after fully charging the battery using the preferred charge method, the battery fails to meet the test criteria of the capacity test, THEN use the conditioning charge procedure.

You may choose not to follow the manufacturer's procedures, but that's what they say to do.
Click to expand...

......
 
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For what it's worth, I just spoke to a very friendly gentleman at Concorde named Skip. He confirmed that my understanding matches their intent: Regardless of the depth of discharge, they always recommend a high-current, constant-potential charge on the battery.

Only if the battery fails a load capacity test after that preferred charge method do they recommend the "plan B" conditioning charge be tried.
 
Tom-D said:
How are they different?
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For the most part, cars no longer come with a starting handle.

Cars don't need a few volts from the battery to turn on a master solenoid like some aircraft.

But, what does the POH say? Sometimes aircraft wiring can be quirky. For example: Cessna 172N POH under "Ground Service Plug Receptacle"

"The battery and external power circuits have been designed to completely eliminate the need to "jumper" across the battery contactor to close it for charging a completely "dead" battery. A special fused circuit in the external power system supplies the needed "jumper" across the contacts so that with a "dead" battery and an external power source applied, turning on the master switch will close the battery contactor."
 
Jim_R said:
For what it's worth, I just spoke to a very friendly gentleman at Concorde named Skip. He confirmed that my understanding matches their intent: Regardless of the depth of discharge, they always recommend a high-current, constant-potential charge on the battery
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that sounds just a little bit like what happens after you start the engine
 
JHW said:
that sounds just a little bit like what happens after you start the engine
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Well, sort of. Except your engine won't start if your battery is "dead". Nor could your alternator support an 8C1 charge rate (8C1=264 A for an RG-35AXC!).
 
Jim_R said:
Well, sort of. Except your engine won't start if your battery is "dead". Nor could your alternator support an 8C1 charge rate (8C1=264 A for an RG-35AXC!).
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Note that the OP said UP TO an 8C1 rate. I'm no battery chemist, but in a few years of bending wrenches, I've found that a pretty good whap (whap, that's a technical term, you'll get used to it) with a high current for a couple of minutes gets the little electrons to dancing around so that a normal charging current can bring the battery back.

As to the fellow who wants to save his baby by putting in a new battery, may I introduce you (no pun intended) to the infant mortality rate of mechanical devices? New stuff fails a LOT more often than something new off the shelf that hasn't been around the block a few times. Try recharging it with the whap-slow charge method and see what you find.

Jim
 
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