New battery time?

[MikeOH]

I've had my M20F three years and its Concorde RG35 may be EOL...log book shows it was installed in 2011 (of course it's possible it's been replaced since with no entry).

Last two times I flew it the prop seemed a bit slow but it always starts in a blade or two, so I didn't dwell on it. But, on a hot start it stopped on a compressions stroke a couple of times before I got it started.  The hot start was Monday after getting fuel.  Yesterday was the second flight but I just did some T&Gs (oh, the horror. I know).  But, when I was starting, I noticed that right after start I was seeing about 3/4 deflection on the ammeter.  After taxi and run up it was back to zero.  But, normally I don't see that high a charge right after a typical one/two blade start (which this was).

No, I don't know when the battery was last load tested, and I doubt it was done at annual last January.

It looks like a new one is around $350, so I'd like not to jump to the conclusion it's the battery.  I have a flight tomorrow and have time to put in a new battery in the morning, but it's not likely I can find an A&P to load test tomorrow morning and still get the battery installed.

Anything else that is likely to have failed, or is replacing the battery without further troubleshooting a pretty good $350 bet?

[hmasing]

I'm in the same boat - I have a battery conditioner on it whenever the plane isn't running, and it just doesn't hold a charge any longer.  

I have heard from local Mooney owners that they have gotten a field approval for an actual car battery from the FSDO - I am looking in to that, hoping to get the details.  Will post ASAP if I can.

[Hank]

@MikeOH, 9 years on a Concorde is prettt good. Go ahead and swap it out,  proactively is always better. I replaced my first one at 6+ years because it was getting slow and I was about to head into the boonies. Nothing to feel bad about . . . .

[MikeOH]

Just now, Hank said:

@MikeOH, 9 years on a Concorde is prettt good. Go ahead and swap it out,  proactively is always better. I replaced my first one at 6+ years because it was getting slow and I was about to head into the boonies. Nothing to feel bad about . . . .

Thank you!  I think I'll get up early tomorrow and head over to AircraftSpruce.

[Hank]

2 minutes ago, MikeOH said:

Thank you!  I think I'll get up early tomorrow and head over to AircraftSpruce.

That's a good plan! For me, it's a 40-minute flight, and they pick me up from down the ramp (FAA blocked their access) and deliver me back to my plane to load up.

[Ragsf15e]

Pretty easy swap, even for a non-A&P.  I did mine last year.  You should have a torque wrench to get the correct torque on the connections.  If you over do it, you’ll damage the terminals.

[carusoam]

To feel better about your decision... your log entry may have something to identify the actual battery... a serial number, or the battery may get marked by a sharpie with the month and year...

If you have a proper BatteryMinder you can borrow... this may get you another month or two to organize your purchase...
 

Define Mooney efficiency...  One battery every nine years...   

PP thoughts only, not a mechanic...

Best regards,

-a-

[MikeOH]

1 hour ago, carusoam said:

To feel better about your decision... your log entry may have something to identify the actual battery... a serial number, or the battery may get marked by a sharpie with the month and year...

If you have a proper BatteryMinder you can borrow... this may get you another month or two to organize your purchase...
 

Define Mooney efficiency...  One battery every nine years...   

PP thoughts only, not a mechanic...

Best regards,

-a-

I looked up the S/N in the log. book, but have not been to the hangar to verify.  I'll do that tomorrow, but really need to already have the battery in order to make my departure time.  I do have a battery minder (PO included it with the sale) but have never used it; never needed it as I typically fly 2 to 3 times per week.  20-20 hindsight is I should have hooked it up yesterday after my flight! Oh, well.

Yeah, if it turns out it's really 9 years old I'm not going to be too upset!  I am a CB, but that might be pushing things to expect a decade!

[jaylw314]

6 hours ago, MikeOH said:

I've had my M20F three years and its Concorde RG35 may be EOL...log book shows it was installed in 2011 (of course it's possible it's been replaced since with no entry).

Last two times I flew it the prop seemed a bit slow but it always starts in a blade or two, so I didn't dwell on it. But, on a hot start it stopped on a compressions stroke a couple of times before I got it started.  The hot start was Monday after getting fuel.  Yesterday was the second flight but I just did some T&Gs (oh, the horror. I know).  But, when I was starting, I noticed that right after start I was seeing about 3/4 deflection on the ammeter.  After taxi and run up it was back to zero.  But, normally I don't see that high a charge right after a typical one/two blade start (which this was).

No, I don't know when the battery was last load tested, and I doubt it was done at annual last January.

It looks like a new one is around $350, so I'd like not to jump to the conclusion it's the battery.  I have a flight tomorrow and have time to put in a new battery in the morning, but it's not likely I can find an A&P to load test tomorrow morning and still get the battery installed.

Anything else that is likely to have failed, or is replacing the battery without further troubleshooting a pretty good $350 bet?

My ammeter goes to +/- 30 amps, so if you're seeing 24 amps after starting that's darned high.  I think I only see 7-8 amps after starting up while the battery recharges.

That does sound like it would be consistent with a low capacity battery, though, since it would charge at max current and voltage early on.

You can do a quick-and-dirty load test yourself.  Just turn on your master and run enough stuff to get about -15 amps on the ammeter, and let it sit for 30-60 minutes (don't let anything overheat.  That should discharge 7.5-15 amp-hours on your battery.  Let the battery sit overnight, then check the no-load voltage.  Lead acid battery no-load voltage corresponds pretty accurately with percent charge, and you can find a chart only to figure what the present capacity is.  So if I know I ran off 10 amp-hours and the battery voltage says I'm 50% discharged, I know I only have 20 amp-hours of actual capacity.  If you wanted to be even more accurate, you can just use a battery charger that keeps track of the amp-hours used for charging.

Your RG-35 should have a rated capacity of 29 amp-hours, so in this case you would have lost about 35% of your capacity.

[Jim Peace]

6 years on the concord with a sky tech starter.....no battery minder....sometimes go 3 weeks without a flight....seems strong....

I can tell you this...my friends with battery minders always seem to have issues......just saying....

[MikeOH]

2 minutes ago, Jim Peace said:

6 years on the concord with a sky tech starter.....no battery minder....sometimes go 3 weeks without a flight....seems strong....

I can tell you this...my friends with battery minders always seem to have issues......just saying....

That's interesting info about battery minders...one of the reasons I haven't used mine is that it always seemed to me that doing ANYTHING electrical TO a battery is not the best idea in the world.  Yeah, I know the fancy battery minder is more sophisticated than a simple trickle charger, but I bet it's 'pulsing' the battery periodically.  Not much, but just never seemed like a good idea to constantly be doing that.  Makes more sense to me to check charge state every month if you're not flying and just bring to full charge and then disconnect.

I have the same setup: Concorde and SkyTech.  I'm on my way to pick up the battery in a few minutes; 9 years is pretty good, IMO!

[aviatoreb]

The timing on this thread is amazing - I literally just got on to see what people's thoughts are regarding when is it time to change out for new battery, and what do you know - this is a current thread running right now.

So is that the answer - if it is starting to get slow to turn over on start up and it has some good years on it then that's it - time to think about a new battery (or two in my case since I have a pair)?  (Despite that I too have a battery minder on it full time when sitting in my hangar).

E

[Jim Peace]

20 minutes ago, aviatoreb said:

The timing on this thread is amazing - I literally just got on to see what people's thoughts are regarding when is it time to change out for new battery, and what do you know - this is a current thread running right now.

So is that the answer - if it is starting to get slow to turn over on start up and it has some good years on it then that's it - time to think about a new battery (or two in my case since I have a pair)?  (Despite that I too have a battery minder on it full time when sitting in my hangar).

E

how old is your battery?

[aviatoreb]

9 minutes ago, Jim Peace said:

how old is your battery?

9 years.

[MikeOH]

1 hour ago, aviatoreb said:

9 years.

Load test is the sure fire way to know.

[aviatoreb]

34 minutes ago, MikeOH said:

Load test is the sure fire way to know.

Thanks! - yeah - just texted with the A&P.  

[carusoam]

Mags and batteries are best on separate schedules...

So... if you have a pair, that are getting old... swap one out just to have it to be fresh, while testing the limits of age on the other one... 

PP thoughts brought on by the fact both my mags are the same age, so are my batteries...

Best regards,

-a-

[aviatoreb]

27 minutes ago, carusoam said:

Mags and batteries are best on separate schedules...

So... if you have a pair, that are getting old... swap one out just to have it to be fresh, while testing the limits of age on the other one... 

PP thoughts brought on by the fact both my mags are the same age, so are my batteries...

Best regards,

-a-

Is that right?

for small double a’s if the batteries are not the same age then a fresh one and an old one sometimes leads to a burst battery ruining the toy.

so my knee jerk is when it comes to batteries that they should be roughly equal if they are a pair.

otherwise I like your idea to stagger schedules and I would certainly be in a position to do just that right now.  
 

what’s right?

[Ragsf15e]

We probably shouldn’t rely on batteries getting slow to turnover the engine as our guide for replacement.  Maybe that’s fine in our car (and what I do), but the battery in my airplane is a huge safety factor when I’m IFR.  Just because it can start the airplane, doesn’t mean I’ll get my 30 minutes (minimum) if the alternator dies.  In my opinion, it’s $~300 well spent to change that thing out as soon as it hits the limit on the standard capacity check which should be done each annual.  Especially critical if you use a battery minder (as i do) because it will still crank fine but could have limited total capacity.

Not that 30 minutes of battery life is gonna be perfect if you’re ifr, but at least it will allow “graceful degradation” for your nav, comm, transponder, etc.  

[carusoam]

41 minutes ago, aviatoreb said:

Is that right?

for small double a’s if the batteries are not the same age then a fresh one and an old one sometimes leads to a burst battery ruining the toy.

so my knee jerk is when it comes to batteries that they should be roughly equal if they are a pair.

otherwise I like your idea to stagger schedules and I would certainly be in a position to do just that right now.  
 

what’s right?

+1 for the capacity check at annual being the good guidance.... or any time there is a question about battery life, no need to wait...

The Long bodies have a pretty complex system of charging one battery at a full rate, while trickle charging the other battery at a float rate...

So... both batteries are not quite equal, and could be off from each other after a heavy start load...
 

My gill batteries got swapped every other year... one battery per year... they even had a nice Gill battery charger to try and save them...

 

When it comes to dissimilar batteries... I am still concerned enough... that I tossed both Gills to get a pair of Concordes...
 

Beyond that... The system to handle two dissimilar batteries is pretty good...  It probably uses a couple of those one way electron valves... (Diodes)... to keep the electricity flowing the right direction...

This is all in the electrical diagrams for the Long bodies.... the Rocket, would need to have a similar Wheatstone bridge looking device in its electrical drawings...

Something needs to be there to keep one bad battery from completely draining the other... leading to possible over heating and acid leaks...
 

Comfortable with...

• same battery brand
• same battery type
• various ages or capacity/strengths batteries

 

Less comfortable with...

• mixing battery types
• mixing battery brands
• having a dead battery connected to the system, to maintain WnB... (disconnect it electrically)

 

The system relies on many things working properly...

Oddly, the BatteryMinders of the world are complex and use some computer like logic to run the various charging and desulfating activities...  I don’t think our voltage regulators are as smart... (they might be, I would have to look closer....) 

 

PP thoughts only based on fuzzy memories of the past...

Best regards,

-a-

[Hank]

3 hours ago, aviatoreb said:

Is that right?

for small double a’s if the batteries are not the same age then a fresh one and an old one sometimes leads to a burst battery ruining the toy.

so my knee jerk is when it comes to batteries that they should be roughly equal if they are a pair.

Your small batteries perform better when replaced together because you use both of them together. Your Mooney only uses one battery at a time, right? Select Battery #1 for this flight, then use Battery #2 for the next flight. Where's the need to replace them at the same time?

P.S.--"my" Mooney only has one battery . . . .

[ArtVandelay]

Your small batteries perform better when replaced together because you use both of them together. Your Mooney only uses one battery at a time, right? Select Battery #1 for this flight, then use Battery #2 for the next flight.

But how are they being charged? If together I would change both.

[aviatoreb]

4 hours ago, ArtVandelay said:

But how are they being charged? If together I would change both.

Ok - I checked my log books and - gasp - they are 12 years old.  They still work!  Which is amazing.  Thanks to regular use and a life of full time battery minders.  But sub par - the prop is just not turning over terribly peppy any more on start up - pretty good until more recently.  Through the annuals they were serviced and usual and checked out ok.  So here I am.

But 12 years old - I have decided that yeah - they don't owe me anything more.  I am ordering 2 new replacements of what they are - a pair of Concorde 35's.

8 hours ago, Hank said:

Your small batteries perform better when replaced together because you use both of them together. Your Mooney only uses one battery at a time, right? Select Battery #1 for this flight, then use Battery #2 for the next flight. Where's the need to replace them at the same time?

P.S.--"my" Mooney only has one battery . . . .

I don't select which charges.  They charge together.

So after the A&P takes a peak I am ordering two.  Its time.

[carusoam]

That deserves MS’s Longevity Prize!
 

12 years on a pair of Concorde Batteries?

That... is amazing!

That is sooo good, the Concorde product support engineers will have a hard time believing it...  

Thanks for sharing the details...

Best regards,

-a-

[aviatoreb]

6 minutes ago, carusoam said:

That deserves MS’s Longevity Prize!
 

12 years on a pair of Concorde Batteries?

That... is amazing!

That is sooo good, the Concorde product support engineers will have a hard time believing it...  

Thanks for sharing the details...

Best regards,

-a-

Thank you thank you.  CB honorary of the day.

Honestly - it is amazing since even this winter it was cranking in cold weather albeit a bit less peppy at say 10F than it used to be.  And early spring .... I started thinking hmmm how long is this thing going to last.  A gradual decline that seems to accelerate at some point I guess.