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mooney m20m dead batteries


pkofman

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@OP

I hope you haven't dumped your batteries yet. Main reason, it's hard to imagine both batteries died the same day. Just do what you would do in your wife's car in winter and a failed cold start.

- take both batteries home, for some TLC
- wait until they warm up in your garage, then "slowly" charge (0.5 AMps over night ?), any observations ?
- measure and note voltage after full charge and againĀ  4 hours later,
- if your electronic charger doesn't seem to work, the battery's voltage may be too low, for the measurement circuit, try a constant voltage charger for the first hour, easy does it,
- if the battery seems ok, put her back into the plane, turn on a few lights and a radio, and draw 1.5 A max.
- wait and see what happens, turn everything off, wait a few hours (or longer) and try again,
- is she holding charge, has the voltage dropped, etc.
- use these data for guided troubleshooting (you'll find the flow charts on the internet).
- repeat with 2nd battery

This won't bring a dead battery back to life, but you wanna double check before you dump 750$, no ?

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27 minutes ago, j3gq said:

@OP

I hope you haven't dumped your batteries yet. Main reason, it's hard to imagine both batteries died the same day. Just do what you would do in your wife's car in winter and a failed cold start.

- take both batteries home, for some TLC
- wait until they warm up in your garage, then "slowly" charge (0.5 AMps over night ?), any observations ?
- measure and note voltage after full charge and againĀ  4 hours later,
- if your electronic charger doesn't seem to work, the battery's voltage may be too low, for the measurement circuit, try a constant voltage charger for the first hour, easy does it,
- if the battery seems ok, put her back into the plane, turn on a few lights and a radio, and draw 1.5 A max.
- wait and see what happens, turn everything off, wait a few hours (or longer) and try again,
- is she holding charge, has the voltage dropped, etc.
- use these data for guided troubleshooting (you'll find the flow charts on the internet).
- repeat with 2nd battery

This won't bring a dead battery back to life, but you wanna double check before you dump 750$, no ?

I agree - it's good to check them out. However, Gills in the long body Mooneys seem to last two years no matter what you do.

Ā 

Gills are about $450 USD each (he has two batteries, so $900) and seem to last two years ($450/yr).

Concordes are about $650 USD each ($1300) and seemĀ to last at least 5 years ($260/yr) with many people getting 7 years ($186/yr).Ā 

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Great fin and tech analysis, Lance!

Making the decision may requireĀ trust in your MS partners...?

Going all in...?

Two batteries, BatteryMinder, Y-wires and plug installed... probably close toĀ an AMU when complete...

Good to have anĀ AS discount if you have one available...

When done... and the engine starts each time with a few blades going by... Price-less! (Borrowed ad from Master Card)Ā :)

PP thoughts only, not a mechanic...

Best regards,

-a-

Ā 

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On 11/6/2019 at 11:10 PM, carusoam said:

Great fin and tech analysis, Lance!

Making the decision may requireĀ trust in your MS partners...?

Going all in...?

Two batteries, BatteryMinder, Y-wires and plug installed... probably close toĀ an AMU when complete...

Good to have anĀ AS discount if you have one available...

When done... and the engine starts each time with a few blades going by... Price-less! (Borrowed ad from Master Card)Ā :)

PP thoughts only, not a mechanic...

Best regards,

-a-

Ā 

So I had the plane charged up Then I tested the start upĀ 

it started on #1. I was able to start on number 1.Ā 
Initially the batts before ChargĆ© were 24 and 20 Ā voltsĀ on one and two respectively.Ā then I ran the plane for a while and they both were the same and able to start the plane. Ā 
Ā 

but tonight I went back and the number 2 was down to 19 againĀ 

I donā€™t know ,call me crazy but 2 years seemssĀ outrageous for a battery life in 2019 Ā my car survives -30c endlessly in the winter here in canada Ā  Rip off !!!Ā 


Ā 

Ā 

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PK,

I went about 16 years staying with Gill batteries... from being outside all the time... pre-MS...

I couldnā€™t discern a difference...

Too expensive to experiment with others....

Ā 

There are some products that barely meet spec and never change...

Finally somebody has enough of it,Ā and writes about it honestly...

Then you find a whole community saying they have the same experience...

Ā 

At least with batteries... they fail before you are in the air...

Could be that the Gill batteries just donā€™t work for Mooneys... the whole array of Mooneys... 12v and 24v, used often or monthly, in warm environments,Ā or cold... fancy chargers built by Gill, or basic chargers...

Does MS have a Gill guy? Ā Be nice, he probably needs a friend...Ā :)

Ā 

Now... if you are a fan of the Champion spark plugs... another example of a product that never worked right for anyone... they kinda worked... then their internal resistance increased until they didnā€™t work...

PP thoughts only... not a mechanic.

Best regards,

-a-

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I agree - it's good to check them out. However, Gills in the long body Mooneys seem to last two years no matter what you do.
Ā 
Gills are about $450 USD each (he has two batteries, so $900) and seem to last two years ($450/yr).
Concordes are about $650 USD each ($1300) and seemĀ to last at least 5 years ($260/yr) with many people getting 7 years ($186/yr).Ā 

I got only 2 years out of my Concorde, 3 from the Gill. But I change them out at first sign of weakness. I get 5 years out of my boat batteries (AGMs) and car batteries.


Tom
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I bought my current 1993 Mooney M20M in 2015. Looking through the logbooks it had Gills replaced every two years like clockwork. The Gills were weak on pre-buy. The first thing I did was buy Concordes and haven't looked back. I did the same in other Mooneys I've owned and had much better success with Concordes. Keeping them de-sulfated will add to their life.

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Ok here is another angle. Ā Can I replace one for the moment. Ā Letā€™s say I put the best battery I own on number 2 and itā€™s a gill and I install a Concorde in number 1. Ā Is that heresy. Can one have dissimilar batteries or is that just me being and engineer and over thinking the situation
The batteries are different Ā sealed or closed Ā  Does it matter????

thoughts.Ā 
Sorry image below was rotated...when uploadedĀ 

C7F9107C-EA35-435A-ACEB-9505A3C566A7.jpeg

Edited by pkofman
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What voltage is the alternatorĀ producing when the engineĀ is running?Ā  This can directly affect the charge level achieved when shut down after a flight. The regulator in my airplane was set to under 13 volts and I adjusted it to 13.7 (i think, its been 3 years).Ā  Ā When I put the battery minder on after flyingĀ  it switches to float mode within a couple of minutes.

I have a Concorde RG series which is a valve regulated lead acid.Ā 

The Concorde owners manual says the recommended voltage regulator setting for 0..15 deg C is 14.25 to 14.5 volts.

I think this is a pervasive problem with airplanes.Ā  Over the years I have seen many airplanes with marginal charging that leave battery undercharged.Ā  The battery charge state should be measured with a voltmeter and the master off.Ā  Its worth the effort to know what you are getting.

So lets hear it,Ā  what does the voltage indicator report with the engine running....

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2 hours ago, pkofman said:

Ok here is another angle. Ā Can I replace one for the moment. Ā Letā€™s say I put the best battery I own on number 2 and itā€™s a gill and I install a Concorde in number 1. Ā Is that heresy. Can one have dissimilar batteries or is that just me being and engineer and over thinking the situation
The batteries are different Ā sealed or closed Ā  Does it matter????

thoughts.Ā 
Sorry image below was rotated...when uploadedĀ 

Ā 

You can have dissimilar batteries (One Gill and One Concorde) but you can't have one good batteryĀ and one weakĀ battery (doesn't pass capacity test)Ā Ā and stillĀ be considered airworthy. Just like you can't have one good mag and one bad mag and still be considered airworthy.

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23 minutes ago, LANCECASPER said:

You can have dissimilar batteries (One Gill and One Concorde) but you can't have one good batteryĀ and one weakĀ battery (doesn't pass capacity test)Ā Ā and stillĀ be considered airworthy. Just like you can't have one good mag and one bad mag and still be considered airworthy.

I know I read that somewhere a long time ago, but can't find it in the POH of either the M20M or M20R. Ā Did you?

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48 minutes ago, donkaye said:

I know I read that somewhere a long time ago, but can't find it in the POH of either the M20M or M20R. Ā Did you?

I took the M20M Flight Safety course in San Antonio in 1996Ā and they emphasized that you needed two good batteries to be legal for take-off. (The trick question was since you have two batteries, if one is discharged are you still legal for take-off. The answer was "No").Ā 

The M20M POH says the same - that two operableĀ batteries are required.

1728411305_ScreenShot2019-11-10at10_23_18AM.thumb.png.aea79027f0b067124b089a9db622bfe1.png

Ā 

Ā 

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1 minute ago, LANCECASPER said:

I took the M20M Flight Safety course in San Antonio in 1996Ā and they emphasized that you needed two good batteries to be legal for take-off. (The trick question was since you have two batteries, if one is discharged are you still legal for take-off. The answer was "No").Ā 

I took the Flight Safety Course in SAT, also in 1992. Ā Still, in the POH it just says don't try to start the airplane with both batteries dead. Ā I assume they mean no external start. Ā I asked,Ā Mark, from Top Gun last week and he confirmed he wasn't aware of a one battery limitation.

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With many owners not checking the battery capacityĀ every year Iā€™m sure many are flying around that donā€™t meet spec. Heck most of the older planes with only a single 12 volt battery and noĀ backup alternator just wait until the starter stops working before the battery is changed out.Ā 

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Two installed and operableĀ batteries are required per the limitations section of the AFM shown above for any of the kinds of operation specified. Per FAR 23.2620, the limitations section is the only section of the AFM requiring FAA approval. Note thatĀ there is a change bar for the battery entry, so this limitation may be different in some AFMs. The LimitationsĀ in the AFM of current revision for your aircraft is legally binding.Ā 
Skip

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We use a 24 volt projector bulb (200 or 250 watts, canā€™t remember off the top of my head) carefully checking the battery voltage and amps every ten mins for the 50 ish min test. Then the battery has to be slowly recharged back to full charge. VERY few shops/individualsĀ will take the time to do this properly...

So they just say itā€™s working properly and carry on.Ā 

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1 hour ago, PT20J said:

Two installed and operableĀ batteries are required per the limitations section of the AFM shown above for any of the kinds of operation specified. Per FAR 23.2620, the limitations section is the only section of the AFM requiring FAA approval. Note thatĀ there is a change bar for the battery entry, so this limitation may be different in some AFMs. The LimitationsĀ in the AFM of current revision for your aircraft is legally binding.Ā 
Skip

Since I'm not at the airplane but only have the information manual for the M20M, I don't see that statement. Ā Under required equipment it says "Battery", not "Batteries". Ā In the Placard section of the Limitations section it just says, "Both Batteries must be installed", not both Batteries must be Installed and functional". Ā Having said that, it is just common sense to have 2 functional batteries. Ā Where the 2 batteries must be functional issue could arise as a problem would be if you have a failed battery and need to fly to your maintenance shop to get it replaced. Ā  You would need a Ferry Permit in that case if both needed to be functional.

Ā 

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Peter,

Condolences from another freezing Canadian who has been in the same situation.

I did lots of research and came to the following conclusions:

Almost everyone seems to think Concorde will last longerĀ than Gill but neither will last like a car or boat battery. I went with Concorde.

There is fairly good scientific evidence that a desulphating battery minder will keep your battery in good shape longer, but very little evidenceĀ that a worn out battery can be restored with this method. Most of the restoration claims are just that - claims.

Concorde insists that you should buy their very expensive minder because the much cheaper Canadian Tire versions (Wal Mart for you Americans) could damage their expensive batteries. I am skepticalĀ aboutĀ how accurate that claimĀ is, but I didnā€™t want to take a chance so I bought a Battery Minder from Aircraft Spruce made specifically for my Concorde battery.Ā 

I added a plug-in kit routed through the TKS service door and I plug it in after every flight. It shows the battery charge condition and I can always start on the first turn of the prop.

Probably spent too much to be a true Mooney CB, but it gives me peace of mind.

If you ever drop in to CNV8 for a $100 burger, send me a PM and we can share complaints about buying everything we need in US dollars!

Mark

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So...

We mostly agree...

1) a pair of concordes is best...

2) a battery that doesnā€™t pass the capacity test is sub optimal...

3) leaving a battery out of the tail... is a WnB problem.

4) a battery that is requiring a high level of charge over a long period of time is bad for the on board charging system and should be avoided...

5) Charging of one battery is uneffected by the charging of the other battery...

6) It seems OK to mix battery types, battery ages, battery brands, in the two battery system...

7) The POH doesnā€™t seem to mention any mixing of batteries... even though it mentions various batteries that qualify...

Anyone want to cut open a Gill battery to take pictures of why they fail? (Probably not, acid is too dangerous to handle)
Ā 

I believed the system is robust enough to handle different batteries... but,

I went with a pair of Concordes anyways...

Expecting my MS experience to not leave me hanging out to dry...Ā :)

But,... Iā€™m only a PP, not a mechanic...Ā Iā€™m probably in year three with the Concordes...

Ā 

Best regards,

-a-

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