Load Testing Battery

[MikeOH]

Since it's been 3 and a half years since I bought my Concorde RG35AXC, and I don't think it's ever been load tested, I decided to spring for an electronic load: Kunkin KP184 (photo below).

So, this is a PIREP on the Kunkin:  Given the cost was under $200 including tax and shipping the apparent quality is higher than I expected.  While it came with accessories, AC cord, voltage sense BNC-TWP adapter, load wires and lugs...assembly of the load wire to lugs is on you, as is obtaining your own TWP wire (twisted pair).

I topped off the battery with the BatteryMinder and then hooked up the KP184.  The unit went through a quick self test in a few seconds and was already to go in CC (constant current) mode.  Set load current to 33 Amps (Concorde's 1C amp-hour rate for the RG35) and pressed "ON" and started my timer.  Voltage is displayed constantly, as is power, and you can see the voltage 'count down' as the battery depletes.

Exactly 54 minutes later I hit 10.00 Volts (end point voltage for the test per Concorde).  So, 90% capacity (85% is the min).  I feel a lot more confident knowing my battery is still in decent shape.

Time will tell how the KP184 holds up, but for 1/5 of an AMU I'm a pretty happy camper.

 

[toto]

This is interesting. My shop tells me every 1-2 years that my Concorde has failed the capacity test, so I buy a new battery (now $1100) every 1-2 years. It’s probably worth the 0.2AMU just to be able to track this myself. 

[Shadrach]

16 minutes ago, toto said:

This is interesting. My shop tells me every 1-2 years that my Concorde has failed the capacity test, so I buy a new battery (now $1100) every 1-2 years. It’s probably worth the 0.2AMU just to be able to track this myself. 

What kind of battery is $1100? I just put a Concord RG35A in my plane a few months ago. It was ~$450.  

[toto]

29 minutes ago, Shadrach said:

What kind of battery is $1100? I just put a Concord RG35A in my plane a few months ago. It was ~$450.  

[Shadrach]

10 minutes ago, toto said:

 

25% mark up over retail seems reasonable I suppose. I wonder if they get wholesale pricing from the distributor.

[Ragsf15e]

2 hours ago, Shadrach said:

 

25% mark up over retail seems reasonable I suppose. I wonder if they get wholesale pricing from the distributor.

Still, needing a new battery every 1-2 seems odd. My lowly 12v concorde is load tested every year and it’s through 5 so far…

[EricJ]

4 hours ago, toto said:

This is interesting. My shop tells me every 1-2 years that my Concorde has failed the capacity test, so I buy a new battery (now $1100) every 1-2 years. It’s probably worth the 0.2AMU just to be able to track this myself. 

I suspect many shops use inaccurate methods to do the test like the old school way with a stack of headlights or landing lights or something, which is very uncontrolled.  Or maybe they motor the starter and look at sag, and aren't careful about how they do that.   In any case, it's interesting to see that people here who are actually doing legit capacity tests are getting good results.   

[MikeOH]

17 minutes ago, Ragsf15e said:

Still, needing a new battery every 1-2 seems odd. My lowly 12v concorde is load tested every year and it’s through 5 so far…

I'm encouraged by this as it suggests I have a few years left in my Concorde!

However, do you know how your A&P is performing the load capacity testing?   As @EricJ says, how it is done is actually pretty critical for reliable data (true constant current regardless of battery voltage).  In the past I thought about how to test myself and kept coming back to the use of a proper electronic load is really the best way to do this; until recently the units have been too expensive.

[toto]

5 minutes ago, MikeOH said:

I'm encouraged by this as it suggests I have a few years left in my Concorde!

However, do you know how your A&P is performing the load capacity testing?   As @EricJ says, how it is done is actually pretty critical for reliable data (true constant current regardless of battery voltage).  In the past I thought about how to test myself and kept coming back to the use of a proper electronic load is really the best way to do this; until recently the units have been too expensive.

I’ve never seen what they do. They describe it as a capacity testing machine, so I’m guessing it’s some sort of automated thing. I’m pretty disappointed with having to replace a battery so often. One of the last four was replaced just under a year after it was installed, and I filed a warranty claim with Concorde. The shop thinks that Concorde batteries are crap, but I’ve had excellent luck with them (aside from having to buy a new one way too often). 

[N201MKTurbo]

1 minute ago, toto said:

I’ve never seen what they do. They describe it as a capacity testing machine, so I’m guessing it’s some sort of automated thing. I’m pretty disappointed with having to replace a battery so often. One of the last four was replaced just under a year after it was installed, and I filed a warranty claim with Concorde. The shop thinks that Concorde batteries are crap, but I’ve had excellent luck with them (aside from having to buy a new one way too often). 

Did they do any of the reconditioning procedures in the manual, to try to increase the capacity?

[MikeOH]

3 minutes ago, toto said:

I’ve never seen what they do. They describe it as a capacity testing machine, so I’m guessing it’s some sort of automated thing. I’m pretty disappointed with having to replace a battery so often. One of the last four was replaced just under a year after it was installed, and I filed a warranty claim with Concorde. The shop thinks that Concorde batteries are crap, but I’ve had excellent luck with them (aside from having to buy a new one way too often). 

@toto

1-2 years out of Concorde is waaaay out of line with what I've heard, and experienced: my last Concorde (installed by the PO) made it 6 years and, as I said earlier, the current one is at 3 1/2 years and doing well.

Not to disparage your shop but I'd be really suspicious of how they are deciding your batteries are shot.

[Ragsf15e]

1 hour ago, MikeOH said:

I'm encouraged by this as it suggests I have a few years left in my Concorde!

However, do you know how your A&P is performing the load capacity testing?   As @EricJ says, how it is done is actually pretty critical for reliable data (true constant current regardless of battery voltage).  In the past I thought about how to test myself and kept coming back to the use of a proper electronic load is really the best way to do this; until recently the units have been too expensive.

My IA has an (older) legit load tester.  It runs  for an hour or more each time and has programs for the specific battery type/capacity.  Other than that, I don’t have specifics.  They are a flight school and Cirrus Service Center, and they test their own 12v Cessna batteries and 24v Cirrus, so I think it’s done correctly, but electricity is close to magic for me.

[EricJ]

1 hour ago, N201MKTurbo said:

Did they do any of the reconditioning procedures in the manual, to try to increase the capacity?

+1 that the Concorde CMM has procedures for reconditioning the battery if it fails a capacity test.   They typically pass after a recondition if they're not too old, so the normal procedure on a capacity fail is to recondition it, not throw it out.

If Concordes are repeatedly failing early and it happens so often that the shop thinks they're crap, I suspect the shop far more than the battery.   I retested my six-year old Concorde myself again this year and it still shows >95%.   It's on a minder nearly always when it's parked, which Concorde says helps.

[MikeOH]

9 minutes ago, EricJ said:

+1 that the Concorde CMM has procedures for reconditioning the battery if it fails a capacity test.   They typically pass after a recondition if they're not too old, so the normal procedure on a capacity fail is to recondition it, not throw it out.

If Concordes are repeatedly failing early and it happens so often that the shop thinks they're crap, I suspect the shop far more than the battery.   I retested my six-year old Concorde myself again this year and it still shows >95%.   It's on a minder nearly always when it's parked, which Concorde says helps.

@EricJ

Interesting...mine was just at 90% after 3 1/2 years, yet you are >95% after 6 years!

Leaving a an operating electrical device hooked up unattended to my plane for days has always made me too nervous...maybe I should reconsider!

[Shadrach]

3 hours ago, Ragsf15e said:

Still, needing a new battery every 1-2 seems odd. My lowly 12v concorde is load tested every year and it’s through 5 so far…

Mine went beyond 10 years before it came back under 80%.
Replacing every two years on every aircraft a shop maintains is a good business model if you’re unencumbered by guilt. That is pure margin. 

[dkkim73]

This might be a dumb question, but is something causing the batteries to be abused? E.g. the trickle-charge fuses blown, regulator off, etc? 

[LANCECASPER]

47 minutes ago, Shadrach said:

My went beyond 10 years before it came back under 80%.
Replacing every two years on every aircraft a shop maintains is a good business model if you’re unencumbered by guilt. That is pure margin. 

They probably swap his out with someone else's in the shop and charge them both $1100 plus labor for an $850 battery which neither of them needed . . that's even better margin . . . lol

[Shadrach]

32 minutes ago, LANCECASPER said:

They probably swap his out with someone else's in the shop and charge them both $1100 plus labor for an $850 battery which neither of them needed . . that's even better margin . . . lol

We have a mechanic on the field that almost none of the locals will do business with. He has always seemed like a perfectly nice guy, but all of the old timers refer to him as “Slippery”… Indeed I only recently learned his real name. A very nice lady with a 172 moved in next door. She was gushing about how nice and conscientious her mechanic was.  I was not sure who she was talking about until about six months later when she went into a diatribe peppered with language that I would have never used in front of her.  Slippery strikes again. Airplane now being serviced elsewhere in order to correct a long list of poorly done maintenance or logged maintenance that was not performed.  Slippery has the nicest truck of any of the mechanics on field. He has a few airplanes and boats living in various hangars. I used to think that folks like Slippery were not real but more caricatures of our imagination and that no Mx professional could be that dishonest. I was wrong.

[Jerry 5TJ]

7 hours ago, Shadrach said:

What kind of battery is $1100? I just put a Concord RG35A in my plane a few months ago. It was ~$450.  

An inexpensive one….my Concorde RG46 is around $2200.  The plane uses a pair of them. 

[Shadrach]

15 minutes ago, Jerry 5TJ said:

An inexpensive one….my Concorde RG46 is around $2200.  The plane uses a pair of them. 

we’re speaking in the context of Mooneys. i’m sure the Gulfstream guys can see your $2200 and raise you a few thousand. It’s all relative.  And relative to other Mooney installations, $1100 is salty.
 

 

 

[Ragsf15e]

1 minute ago, Shadrach said:

we’re speaking in the context of Mooneys. i’m sure the Gulfstream guys can see your $2200 and raise you a few thousand. It’s all relative.  And relative to other Mooney installations, $1100 is salty.
 

 

 

Ha! Yeah, our Meridian (work plane) uses a ~$5k concorde!

[GeeBee]

6 hours ago, MikeOH said:

@EricJ

Interesting...mine was just at 90% after 3 1/2 years, yet you are >95% after 6 years!

Leaving a an operating electrical device hooked up unattended to my plane for days has always made me too nervous...maybe I should reconsider!

I leave AGM batteries hooked up to a charger all the time. Especially on my boat. One time my grand kids left the battery on and ran it down to nothing. The boat charger, a 30 amp model charged it until the battery blew. It simply split at the top seam and vented. No spill, no mess. The Battery Minder product is very safe to leave unattended. Safer than the light switch in your hangar. 

[MikeOH]

3 hours ago, GeeBee said:

I leave AGM batteries hooked up to a charger all the time. Especially on my boat. One time my grand kids left the battery on and ran it down to nothing. The boat charger, a 30 amp model charged it until the battery blew. It simply split at the top seam and vented. No spill, no mess. The Battery Minder product is very safe to leave unattended. Safer than the light switch in your hangar. 

While you are entitled to your opinion about the risk of leaving a battery on continuous charge (although your example could have ended with an explosion of hydrogen gas with a very different outcome to your boat), your claim that the Battery Minder is safer than a light switch is complete bullshit.

[N201MKTurbo]

Just remember that not all battery minders are the same.

I think the ideal maintainer would have a temperature sensor so it could adjust the float voltage and open circuit voltage according to temperature. It would also have a setting to change the battery chemistry from flooded cell to AGM. 
 

It would then monitor the open circuit voltage and when it got below the calculated threshold it would start a small (> 200ma) charge current until it got to the calculated float voltage. It would then remove the charge current and wait for the battery to fall below the open circuit threshold again, which could take days.

[GeeBee]

11 hours ago, MikeOH said:

While you are entitled to your opinion about the risk of leaving a battery on continuous charge (although your example could have ended with an explosion of hydrogen gas with a very different outcome to your boat), your claim that the Battery Minder is safer than a light switch is complete bullshit.

Is the power to a light switch always on? Think about it. One wire to that switch is always hot AND there is the ground wire.

As to explosion of hydrogen gas with an AGM, unlikely if you understand the technology. The Battery Minder cannot generate enough amps to make it happen.