Generator or battery problem, or something else...?

[SoccerCA]

I am experiencing an issue that has me a little stumped. Hoping for some ideas from the collective expertise of this forum.

• With engine running above 1,100 rpm, all systems perfectly normal.
• At 1,000 rpm and below, the rhythm of the strobe can be heard on the headset.
• During idle check at runup the avionics briefly reset; they come back on as soon as the throttle is minimally reopened.

This problem is intermittent and cannot be reproduced with any consistency, but has happened more than once.  It started recently, about 1 week ago.

In addition, performed a brief test running off battery power alone (engine off/all avionics and lights on) and could not reproduce the problem.

I also have not noticed any weakness starting the engine.

Thank you in advance for any troubleshooting tips and ideas.

[ShuRugal]

Is this a new development?  That just sounds like generator things to me.  Maybe time to bring your electric system out of the 19th century and put an alternator in?

[takair]

23 minutes ago, SoccerCA said:

I am experiencing an issue that has me a little stumped. Hoping for some ideas from the collective expertise of this forum.

• With engine running above 1,100 rpm, all systems perfectly normal.
• At 1,000 rpm and below, the rhythm of the strobe can be heard on the headset.
• During idle check at runup the avionics briefly reset; they come back on as soon as the throttle is minimally reopened.

This problem is intermittent and cannot be reproduced with any consistency, but has happened more than once.  It started recently, about 1 week ago.

In addition, performed a brief test running off battery power alone (engine off/all avionics and lights on) and could not reproduce the problem.

I also have not noticed any weakness starting the engine.

Thank you in advance for any troubleshooting tips and ideas.

Can you tell us more about what you have?  Airplane model, alternator or generator, old school strobes or LEDs, which avionics reset?  I think Shu is on to it…but more info would help.  Do you have a voltmeter?  Avionics typically reset when dropping below about 10v.  What type of battery and how old.  Some Gills have a habit of failing prematurely and once the generator drops out it may not be holding up your voltage.

[KNorton]

I agree with the previous posts. How old is the battery? Does the starter crank strong? I suspect old battery combined with a bad generator and/or regulator. If the starter is strong then the battery is probably alright.

[81X]

What is your battery voltage at idle check and at run up/cruise RPM?  
 

Sounds like possibly a tired battery that has enough voltage and cranking amps to start the airplane but can’t hold enough voltage.  This could be exacerbated by the fact that generators and even some alternators (such as my gear driven one) don’t produce 13.5 or so volts at idle.  
 

 

[SoccerCA]

26 minutes ago, takair said:

Can you tell us more about what you have?  Airplane model, alternator or generator, old school strobes or LEDs, which avionics reset?  I think Shu is on to it…but more info would help.  Do you have a voltmeter?  Avionics typically reset when dropping below about 10v.  What type of battery and how old.  Some Gills have a habit of failing prematurely and once the generator drops out it may not be holding up your voltage.

1965 M20E, generator, old-school strobes. All avionics reset (comms, navs, S-TEC 30 autopilot).  Gill G35 battery, new in 2013 (according to logs).

I do have a voltmeter and my goal is to try some troubleshooting to determine the actual problem before upgrading perfectly functional parts.

[Shadrach]

1 hour ago, SoccerCA said:

I am experiencing an issue that has me a little stumped. Hoping for some ideas from the collective expertise of this forum.

• With engine running above 1,100 rpm, all systems perfectly normal.
• At 1,000 rpm and below, the rhythm of the strobe can be heard on the headset.
• During idle check at runup the avionics briefly reset; they come back on as soon as the throttle is minimally reopened.

This problem is intermittent and cannot be reproduced with any consistency, but has happened more than once.  It started recently, about 1 week ago.

In addition, performed a brief test running off battery power alone (engine off/all avionics and lights on) and could not reproduce the problem.

I also have not noticed any weakness starting the engine.

Thank you in advance for any troubleshooting tips and ideas.

Do you have a modern gauge that shows bus voltage?  It would be good to know if this is occurring because bus voltage is dropping below a certain threshold.

[SoccerCA]

14 minutes ago, 81X said:

What is your battery voltage at idle check and at run up/cruise RPM?  
 

Sounds like possibly a tired battery that has enough voltage and cranking amps to start the airplane but can’t hold enough voltage.  This could be exacerbated by the fact that generators and even some alternators (such as my gear driven one) don’t produce 13.5 or so volts at idle.  
 

 

Tired battery was my first thought, except that I could not reproduce the problem with the the engine off and the same avionics/lights on...

[Shadrach]

3 minutes ago, SoccerCA said:

Gill G35 battery, new in 2013 (according to logs).

Considering the G35 is just a few rungs above garbage when brand new, I’d start with the 8 year old battery and replace with a sealed battery.

[SoccerCA]

5 minutes ago, Shadrach said:

Do you have a modern gauge that shows bus voltage?  It would be good to know if this is occurring because bus voltage is dropping below a certain threshold.

Sorry, no, it's all old-style instrumentation.

[Shadrach]

4 minutes ago, SoccerCA said:

Tired battery was my first thought, except that I could not reproduce the problem with the the engine off and the same avionics/lights on...

How long did you leave the master on? If you’re taxing at low RPM, the battery is discharging. Flipping the master on for a few seconds in the hangar is not going to reproduce that.

[KNorton]

3 minutes ago, SoccerCA said:

1965 M20E, generator, old-school strobes. All avionics reset (comms, navs, S-TEC 30 autopilot).  Gill G35 battery, new in 2013 (according to logs).

I do have a voltmeter and my goal is to try some troubleshooting to determine the actual problem before upgrading perfectly functional parts.

Start with the battery. Regardless of what the generator/regulator are doing (unless it’s going over voltage), the battery should not allow the avionics to reset. It sounds like it is low after starting, too low to keep the other systems alive. On an 8 year old battery, I suspect it is failing.

If you want to troubleshoot the generator, it can be difficult when it is intermittent. I just lost my generator in-flight a few weeks ago and decided to go with an alternator conversion because it saved time and was an upgrade.

The first things to check, if troubleshooting would be the output voltage at the regulator, the generator belt tension, and the generator brushes. If all that checks out them pull the generator and bench test it.

If you don’t find the problem right away, keep a close eye on your ammeter. If you get zero or discharge in flight then your generator is intermittent and will eventually fail. Brush up on your electrical failure emergency checklist, which is pretty easy on a ‘65. I was glad I had a handheld comm when mine failed.

I hope this helps. Good luck!

[SoccerCA]

5 minutes ago, KNorton said:

Start with the battery. Regardless of what the generator/regulator are doing (unless it’s going over voltage), the battery should not allow the avionics to reset. It sounds like it is low after starting, too low to keep the other systems alive. On an 8 year old battery, I suspect it is failing.

If you want to troubleshoot the generator, it can be difficult when it is intermittent. I just lost my generator in-flight a few weeks ago and decided to go with an alternator conversion because it saved time and was an upgrade.

The first things to check, if troubleshooting would be the output voltage at the regulator, the generator belt tension, and the generator brushes. If all that checks out them pull the generator and bench test it.

If you don’t find the problem right away, keep a close eye on your ammeter. If you get zero or discharge in flight then your generator is intermittent and will eventually fail. Brush up on your electrical failure emergency checklist, which is pretty easy on a ‘65. I was glad I had a handheld comm when mine failed.

I hope this helps. Good luck!

Your analysis sounds perfectly reasonable. Any thoughts about Gill vs Concord nowadays. It appears that Concord used to be the hands-down winner on this forum for many years but I have been reading that Concord made some changes that led to problems in recent years while Gill quality is said to have improved at the same time...

[jamesm]

Not sure if it still out on the  web  but at one time  both plane power and  zeftronics  had excellent trouble  shooting guides online  even know you may not have the plane power or zeftronics  brand installed on your airplane it was very applicable in diagnosing the problem(s).

https://planepower.aero/wp-content/uploads/2018/02/Troubleshooting-Single-Engine-Externally-Regulated-Alternators.pdf

Zeftroincs   voltage regulator (which what I have installed) trouble shooting guide  is probably still out there but it wasn't right off the google search.

Zeftronics  had  a voltage regulator  troubleshooting guide  for the Generator as well. which very tight on the resistance  values but I keep my Airplane  going.

 

Hope this helps,

James '67C

[carusoam]

57 minutes ago, SoccerCA said:

Your analysis sounds perfectly reasonable. Any thoughts about Gill vs Concord nowadays. It appears that Concord used to be the hands-down winner on this forum for many years but I have been reading that Concord made some changes that led to problems in recent years while Gill quality is said to have improved at the same time...

Soccer this is going to be a fun exercise… 

Usually we start with the big stuff… because it matters.

1) Plane…. Mooneys with generators are A, B,C, D, E, F, G…

2) How old is the generator? Original Delco 50Amp with a sticks and stones and springs voltage regulator?

3) How new is the voltage regulator? zeftronics?

4) Strobes are not original to many of these birds…. What strobes do you have?
 

5) Haven’t seen any complaints about Concorde batteries…. Let me know if you can point them out…

The new Gill batteries are being used by a few MSers… but, not a lot of glowing reviews after the sixth year yet…

6) Batteries have a capacity test…  if it passes the test, it probably won’t be the battery… see your mechanic for this…

 

7) Alternators are pretty good at producing current above 1000 rpm…

8) Generators are pretty good at supplying current at much higher rpms…

 

9) Strobes are pretty good at making noise… their power supplies wear over time…

10) How many strobes do you have?

11) What model number are they, how old are they, have you seen the latest from Whelen?

 

12) You know for a few dollars… you can buy a usb plug and volt meter in one device and plug it in the liter socket…  

13) There are things that can be checked for the health of the generator… some small dollar parts…

That will give you a fact based approach to what is going on with your battery and charging system… at the same time you get noise from your strobe system…

PP thoughts only, not a mechanic…

Best regards,

-a-

 

 

[Shadrach]

49 minutes ago, SoccerCA said:

Your analysis sounds perfectly reasonable. Any thoughts about Gill vs Concord nowadays. It appears that Concord used to be the hands-down winner on this forum for many years but I have been reading that Concord made some changes that led to problems in recent years while Gill quality is said to have improved at the same time...

A Gill AGM battery (7035) is a fine battery.  I would avoid buying another wet cell battery. I must say that yours surviving for 8 years makes it a bit of an outlier. I used Gil wet cell batteries for may years. All were below acceptable capacity by year 5.

[Ragsf15e]

12 hours ago, SoccerCA said:

Sorry, no, it's all old-style instrumentation.

Get a voltmeter / cigarette lighter plug in.  At least you’ll have voltage there.  Cheap on amazon and a good start.

[carusoam]

Once you have a volt meter…

Verify the voltage you are seeing… while at max charging… 13+ volts… on a 12V system…

If not getting max volts…

There are things to check from set point of the V regulator to the conditions of the brushes and the commutator…. To the tightness of the belt that drives the generator…

There is a pic around here of completely worn out brushes, replete with a machined out commutator, that was having difficulty producing electricity… Brushes were designed for an low cost easy swap out…

Often a barely loose belt, has enough slip in it… to not drive the generator… and not wear out either….

PP thoughts only, not a mechanic…

best regards,

-a-

[A64Pilot]

Battery being discharged at low RPM with a generator is entirely normal, and generators are fine, no need to spend big bucks replacing one that works just to update the airplane, now if it’s broken, then you have a decision to make.

However I wouldn’t put a Gill wet cell in my lawnmower, I’ve had my boiling over Gill experience putting acid where you don’t want it, never again. Called one trial learning.

If this is a new occurrence I’d say it’s very likely your old battery is losing capacity and voltage is dropping lower than it used to.

If you ever do any IFR toss that battery before next flight, an eight year old battery isn’t likely to have the reserve capacity to get you down if IFR.

Buy a cheap little volt meter that plugs into your cigarette lighter for testing

Edited August 29, 2021 by A64Pilot

[A64Pilot]

Oh, and if you do go to a alternator, remember it’s output isn’t likely what you can use, most probably your electrical system was sized for a generator output, so the extra output of the alternator can’t be used, unless you upgrade the charging side of the electrical system.

In other words if you have a 60 amp generator CB, and install a 100 AMP alternator, the system capacity limits you to 60 amps.

I have no idea what your generator CB size is.

[Shadrach]

On 8/29/2021 at 6:21 PM, A64Pilot said:

Oh, and if you do go to a alternator, remember it’s output isn’t likely what you can use, most probably your electrical system was sized for a generator output, so the extra output of the alternator can’t be used, unless you upgrade the charging side of the electrical system.

In other words if you have a 60 amp generator CB, and install a 100 AMP alternator, the system capacity limits you to 60 amps.

I have no idea what your generator CB size is.

TCDS shows M20E delivered in three configurations - 50amp Delco Remy generator, 60amp Prestolite Alternator and a 70amp Prestolite Alternator. I’d bet the only difference in the charging system of the 3 applications is the CB but maybe it was upgraded for 70s models.

I have thought about “upgrading” to an Alternator but I have never felt a deficit in the electrical system. System is charging  by 1050-1100rpm. 
I also admit to having left the master on a time or two in 25 yeas of flying. I find it comforting to have a charging system that does not need input voltage to make power.  

[A64Pilot]

Ref leaving the master on, I did that once and came back next early morning to a completely dead battery. So off the Walmart to buy two 12V batteries and a short jumper cable. Remove the engine cowling. Start the engine and reinstall cowling with engine running. (C-210)

‘I can hand prop an R-1340, but couldn’t come close on an IO-520, plus the three blade prop scares me.

‘Anyway so now I never turn off the strobes, ever. I find it harder to walk away with the master on if the strobes are popping, they sort of get your attention.

In the Mooney I have a set of jumper cables with one end that has the plug to fit the APU receptacle.

‘I’m often at tiny airports, almost never at bigger ones, and I prefer 12V aircraft because they are so much easier to jump start. Always something around with a 12V battery

 

Only good reason to “upgrade” to an alternator in my opinion is if the weight difference means that much to you. If you have plenty of money and are having to ballast the aircraft anyway, maybe losing the weight does as that means you can lose some ballast too.

I’ll get argument here but generator output is actual real DC and less noisy etc. An alternator makes alternating current that is rectified to pulsating DC, which is then conditioned to smooth power by this huge capacitor we call a battery.

‘Most turbines have a Generator, sure it doubles as a Starter, but if there was anything inherently wrong with a generator, then all those high buck turbines would have an alternator separate from the Starter like us little guys do.

Edited September 1, 2021 by A64Pilot

[Shadrach]

The 4lb loss would be nice but there are other areas where I'd throw $1000.

Our F model has been hand propped but not by me and I would be very hesitant to do it. I was not there but the story goes that a non pilot passenger was in the left seat holding the key in the start position (SOS ignition).  The engine fired on the first blade but the parking brake did not completely hold.. Plane is inching forward...passenger is frozen and will not make eye contact nor perform previously briefed tasks. It is one of our family's more entertaining Dad stories, I've heard it at least 100 times. More colorful parts omitted...