Mind your Battery Minder

[rbp]

A few weeks ago, I went to start up on battery #2 (#1 on odd numbered days, #2 on even), and it wouldn't crank. I talked with the shop about getting a new one, and he checked the logs and noticed that mine is 6 years old, and that it should be replaced after 5, so I planned to get some squawks dealt with and the battery replaced. In the meantime, I would fly on battery #1. 

Yesterday, I went to the hangar for a flight only to find that I had forgotten to plug the battery minder in. It had been 5 weeks since the last time I flew, and there had been a week of sub-freezing temps. When I went to start on #1, it wouldn't start, so double battery failure. Unfortunately, my home airport has no services, and nobody with an open hangar had ground power. 

When I plugged the first battery minder leg in, the little light didn't go on so it seems one of the legs was bad. A bit of swapping, and I was able to trace it to the minder, not in the in-airplane wiring. Popped open the fuse box only to find a blown fuse. Off to Home Depot and I left it overnight to charge.

When I looked at it this morning, the little "full battery" icon was lit, so I felt sure that it would start on the good battery, and indeed it did. On the second flight, I started on the "bad" battery, no problem.

It seems that the "bad" battery was not bad at all, it  was just not getting charged because of a blown fuse on one leg.

So now I am going to plug each leg into the minder separately (before plugging in the minder to shore power), to make sure that it has connectivity to the battery.

Now I'm not sure if its time yet to replace the "bad" battery  

[Guest]

Charge and capacity test the battery to determine its health, likely after 5 years it will fail.

[rbp]

2 minutes ago, M20Doc said:

Charge and capacity test the battery to determine its health, likely after 5 years it will fail.

that's exactly what my son just wrote me!

[Ragsf15e]

41 minutes ago, rbp said:

that's exactly what my son just wrote me!

Just to Echo… i like my minder too, but it can mask a problem. At least one of your batteries should have been capable of starting after a month off, even cold.  Remember, just because they start the airplane doesn’t mean they’ll keep you alive IFR with an alternator failed.

[carusoam]

Six years seems to be a typical life for a Concorde battery…

When you have two, and one fails… expect the life of the other is on short notice… not related to the first failure, just the normal behavior of the device…

+1 for capacity testing… the best way to measure a battery’s health… a good requirement for flying in IMC…

Battery #1 usually shows weakness first… after a Month of not flying…  #1 has the keep alive circuit that keeps all of the radio memories alive…  a month of draining the battery slowly can leave it kinda week…

what killed the fuse in the BatteryMinder?

PP thoughts only.

-a-

[Fly Boomer]

3 hours ago, Ragsf15e said:

Remember, just because they start the airplane doesn’t mean they’ll keep you alive IFR with an alternator failed.

And it doesn't mean it will pass a capacity test.

[PT20J]

26 minutes ago, Fly Boomer said:

And it doesn't mean it will pass a capacity test.

That's the point. The folks that report extraordinary life out of their batteries are just running them to failure. They would get years less life if the replacement criteria were passing the capacity test. If the alternator quits in the clag, that battery capacity is all you have. Lead acid batteries will often provide stating amps without having much capacity (amp hours). It happened to me recently in my Subaru. The car always started fine, but I left a dinky dome light on for an hour and the 6 year old battery was dead when I tried to start it.

Skip

[MikeOH]

@PT20J

So, how many years have you experienced before your battery failed the capacity test 2, 3?

The consensus seems to be that 6 years is an unrealistic expectation.

[PT20J]

1 minute ago, MikeOH said:

@PT20J

So, how many years have you experienced before your battery failed the capacity test 2, 3?

The consensus seems to be that 6 years is an unrealistic expectation.

I bought the airplane in 2018 with a Concorde installed by the previous owner in 2017. I always kept it on a Batteryminder. In 2021 it passed barely after the second try.  I replaced it when I put in the new panel a few months later. So, I'd guess 4-5 years, but it probably varies depending on how the battery has been treated and what temperatures it has been subjected to. I replaced it with a Gill sealed battery which was cheaper and slightly higher capacity than the Concorde. We'll see what it does.

[carusoam]

Very few pireps on the Gill sealed batteries…

There are a few around here… but not very old yet…

Looking forward to Gill having a great battery… Concorde needs the competition.   0.6amus grumble grumble grumble…. 
 

Go capitalism!

Best regards,

-a-

[Fly Boomer]

7 hours ago, PT20J said:

It happened to me recently in my Subaru. The car always started fine, but I left a dinky dome light on for an hour and the 6 year old battery was dead when I tried to start it.

I had a similar experience with my Prius.  The 12-volt battery is not used to start the engine, so it is tiny, and something must have been left on.  Parked it one evening, and everything was fine -- next morning, dead.  And when I say dead, I mean it wouldn't even light the dome light dimly.  I didn't even try to charge it.  It was eight years old, so I just put in a new one.

[Will.iam]

3 hours ago, Fly Boomer said:

I had a similar experience with my Prius.  The 12-volt battery is not used to start the engine, so it is tiny, and something must have been left on.  Parked it one evening, and everything was fine -- next morning, dead.  And when I say dead, I mean it wouldn't even light the dome light dimly.  I didn't even try to charge it.  It was eight years old, so I just put in a new one.

I have a camry hybrid and the same setup the 12 volt battery is used to keep the computers and accessories going. The traction hybrid battery pack is the one that carries the heavy loads like started the engine running the A/C and electric drive motors. Mom bought that car new in 2007 and I inherited it in 2017 only when i put in a gps dash camera and backup cam that records even when parked did the 12 volt battery finally die. 10 years can’t complain on that but a new one with it’s proprietary drain tube and temp sensor was $350! But if it goes as long again compared to regular battery it will be worth it. 

[Fly Boomer]

1 minute ago, Will.iam said:

I have a camry hybrid and the same setup the 12 volt battery is used to keep the computers and accessories going. The traction hybrid battery pack is the one that carries the heavy loads like started the engine running the A/C and electric drive motors. Mom bought that car new in 2007 and I inherited it in 2017 only when i put in a gps dash camera and backup cam that records even when parked did the 12 volt battery finally die. 10 years can’t complain on that but a new one with it’s proprietary drain tube and temp sensor was $350! But if it goes as long again compared to regular battery it will be worth it. 

I know what you mean.  I love to complain that "they just don't make 'em like they used to" but ten years is amazing.  I was complaining that my factory tires only went 90,000.  Could have gone to 100,000 just for bragging rights, but it was starting to get squirrely in the slick.  I've never in life had a set of tires last so long -- especially factory tires.  And 150,000 on factory brakes, windshield wipers, etc.  Best car I have ever owned.  Not sexy, but bulletproof.

[DXB]

On a related note, I've been fooled into thinking my Battery Minder was dead when actually the 10A fuse in the connector cable between the Minder and the battery had blown.  

Unfortunately relatively few shops have proper capacity testers, and one could by a lot of batteries for the price of buying a capacity tester yourself.  Without ready access to one, I think it's now my default to replace my Concorde between year 4 and 5 or at first sign of issues.  A strong battery is such an important system in face of an alternator failure, particularly in a single battery alternator plane, that keeping a good condition battery should be viewed as paramount to safety.  This is even more true now with so many of us having Surefly mags, which have a small draw from the battery even when the plane is sitting with master - also making a Battery Minder even more important.

Hopefully the emerging Lithium batteries for planes will add some battery longevity and greater reliability to the electrical system when the STCs become available. 

 

 

[rbp]

2 hours ago, DXB said:

On a related note, I've been fooled into thinking my Battery Minder was dead when actually the 10A fuse in the connector cable between the Minder and the battery had blown.  

 

yes, it was the 15A (bottom, now dark blue) fuse in the Y connector

[jetdriven]

We use a capacity tester.  It puts a load on it and you time it. 

[Will.iam]

Why not as a poor man or CB load tester, just turn all your avionics on for an hour and see if they are still running after the hour. You could even play with your garmin figuring out system menus and settings. Make a few radio calls turn up your light lights etc Because isn’t that really what you need the battery to do? Run everything for an hour plus?

[MikeOH]

4 minutes ago, Will.iam said:

Why not as a poor man or CB load tester, just turn all your avionics on for an hour and see if they are still running after the hour. You could even play with your garmin figuring out system menus and settings. Make a few radio calls turn up your light lights etc Because isn’t that really what you need the battery to do? Run everything for an hour plus?

SHEESH!  What's wrong with you?  That's just entirely too practical, logical, and reasonable a test for aviation!

[DXB]

35 minutes ago, Will.iam said:

Why not as a poor man or CB load tester, just turn all your avionics on for an hour and see if they are still running after the hour. You could even play with your garmin figuring out system menus and settings. Make a few radio calls turn up your light lights etc Because isn’t that really what you need the battery to do? Run everything for an hour plus?

I think that might cause a deeper discharge and thus more harm to the battery than a capacity tester? I’m not sure though.

[MikeOH]

13 minutes ago, DXB said:

I think that might cause a deeper discharge and thus more harm to the battery than a capacity tester? I’m not sure though.

A rational question but let's consider the logical consequence:  If the battery capacity test is LESS severe than running your avionics for an hour then what confidence would you really have after a successful load test that you could actually fly for an hour in an emergency?

[Rick Junkin]

https://resources.savvyaviation.com/wp-content/uploads/articles_eaa/EAA_2011-07_battery-tlc.pdf

The whole article is very useful and informative, but page 3 tells you how to perform a "poor man's capacity test". I've used this myself with great success. @Will.iam was spot on, although only turning on a known equipment load makes the test more accurately quantifiable.

Cheers,
Rick

[slowflyin]

12 hours ago, jetdriven said:

We use a capacity tester.  It puts a load on it and you time it. 

same

[A64Pilot]

12 hours ago, Will.iam said:

Why not as a poor man or CB load tester, just turn all your avionics on for an hour and see if they are still running after the hour. You could even play with your garmin figuring out system menus and settings. Make a few radio calls turn up your light lights etc Because isn’t that really what you need the battery to do? Run everything for an hour plus?

While that may work to test the battery, it’s probably not good for the avionics, they are made for 14 or 28V and running on lower voltage usually means more heat.

Best to take the batteries out and use some form of dummy load, light bulbs, car headlights for a 12V airplane is fine. technically they are not perfect as the voltage decreases so does the load, but they are certainly good enough.

Attached photo is a light bulb dummy load used for Certification test flight where we had to load the Starter / Generator to max load. They were 800W ea if memory serves and in the hopper that we had to fill with water to keep it from catching fire, but everything else was bunches of $$$..

If the OP had Concorde’s, the self discharge rate for them even in cold weather is in many months, meaning if they were good, then they would start the airplane months after it had last run, the battery minders are most likely masking bad batteries.

 

[N201MKTurbo]

22 hours ago, Fly Boomer said:

I know what you mean.  I love to complain that "they just don't make 'em like they used to" but ten years is amazing.  I was complaining that my factory tires only went 90,000.  Could have gone to 100,000 just for bragging rights, but it was starting to get squirrely in the slick.  I've never in life had a set of tires last so long -- especially factory tires.  And 150,000 on factory brakes, windshield wipers, etc.  Best car I have ever owned.  Not sexy, but bulletproof.

When I sold my Tacoma, it had 186000 miles. It still had the factory brakes and only the second set of tires, which still had plenty of tread.

Back in 2007 I started practicing hypermiling and still do. Using your brakes is just pouring gas on the ground. You can tell if you are driving efficiently. If you get better mileage in town than on the highway, you are driving efficiently. I got my son and wife to do it. My wife went from an average MPG of 17 to 24 in her Highlander. My son has an F150 and he can get 23 MPG if he tries. He doesn't try that much.

[Fly Boomer]

2 minutes ago, N201MKTurbo said:

Using your brakes is just pouring gas on the ground.

I try to imagine that the brake pedal is connected to a petcock in the fuel system.  Any time you have your foot on the brake pedal, the petcock is open -- dribbling fuel out onto the pavement.  Sometimes other drivers get frustrated with me.