Battery replacement as private pilot questions..

cowman

cowman

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Cowman
Aircraft is a Piper PA-32R-300 Lance, I'm a Private Pilot owner/operator. The A&P I used to go to on field passed away last year so a lot of stuff I just got handled I'm now doing on my own until I get set up with someone at a neighboring airport...

Anyway I just had to get my plane jump started due to a weak battery, had been sitting for almost 6 weeks. Battery wasn't flat just a little too weak but I've owned this plane for a while and never replaced the battery. I see that the battery was last replaced in Jan 2017 so over 6 years old. P/N listed in logs is RG35AXL.

I can't find an RG35AXL anywhere, however the Concorde application guide on spruce lists a few batteries including an RG-35AXC.

I know I can change a battery as a private pilot owner but I vaguely remember something about it having to be same part# is that right? Is the RG35AXL listed in my logs discontinued or did someone possibly fat-finger that into the logs? I've got to go back to the airport and empty out my front baggage compartment and pull the floor up to be able to physically look at the battery.

I'm comfortable changing my battery, I just want to make sure it's all legal and loggable before ordering one.
https://www.aircraftspruce.com/catalog/elpages/rg_35axc.php


*edit
another question- do these things come with the electrolyte in a jug that you have to add to the battery to activate it? I'm comfortable doing that too but if my current battery is still good that would make me feel better about ordering it preemptively knowing I can store it on a shelf until needed.
 
Yeah, you have to add the electrolyte and charge the battery after you buy it. It has been awhile since I bought one, so I can't remember what the warranty on the battery is. I assume from the purchase date, not from the time you add the electrolyte. Check with the battery manufacturer's literature to make sure it is PMA approved for your aircraft.
 
Yes you can do it and log it. The concord battery is sealed and it comes ready to go.
 
My mistake. Last time I bought aircraft lead acid batteries, they all needed to be charged with electrolyte. I have only been buying lithium ion batteries lately for the experimental plane.
 
cowman said:
I've got to go back to the airport and empty out my front baggage compartment and pull the floor up to be able to physically look at the battery.
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Do this prior to ordering. Look on the battery itself. Another place to look is your Equipment List for a P/N as this should have been updated also. Issues could pop up when trying to substitute a different P/N. But I think you probably have a AXC installed so it should be a straight forward replacement and don't forget your write up per Part 43.9.
 
Rob58 said:
You may find it helpful to refer to page 12 of AC 23-27 in which it provides some guidance on battery substitution. https://www.faa.gov/regulations_pol...fm/go/document.information/documentid/1021446
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Code: 
2. BATTERIES. If one type of series 35 battery (e.g. a Gill 35) is approved as original
equipment or a PMA part, and another type of series 35 banery ( e.g. a Concord 35) is PMA
approved for some aircraft models but not your model aircraft, you may install the alternate type
of series 35 battery and document the installation with only a logbook entry. This applies to all
series 35 batteries.
...
Approval: This is a minor alteration and you may document it by a logbook entry. The logbook
entry must reference the original and replacement manufacturer's identification or the
performance specifications of the original and replacement battery.

So does the fact that it's a minor alteration make it outside the scope of "preventive maintenance"?
 
asicer said:
So does the fact that it's a minor alteration make it outside the scope of "preventive maintenance"?
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Yes. But only under the AC. The Concorde installed in the OPs aircraft is PMA'd so it is a legal replacement part vs an alteration per se.
 
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So, it seems like the following would be in order....

Go out to the airport tomorrow and do a condition test by attempting to start the airplane. Flew 1.7hrs today so it should have charged. If it cranks weak or not at all I'm fine assuming this 6yo battery is done. In that case, get into the battery box to verify what's in there and place an order for a five hundred freakin' dollar battery.

If it fires right up then I get decide if I want to just replace on age and the one day of not quite enough juice to turn it over or not.
 
Forgive me if you already know this.

If you disconnect the Ground Lead first and install it last you may avoid

unwanted “ excitement”.

Sparks are only desirable INSIDE the engine!


Concordes specify a rather low torque for the terminals. If you don’t have a

1/4 inch Torque Wrench it is well worth while getting one.

Even Harbor Freight Aircraft Supply beats guessing.
 
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cowman said:
So, it seems like the following would be in order....

Go out to the airport tomorrow and do a condition test by attempting to start the airplane. Flew 1.7hrs today so it should have charged. If it cranks weak or not at all I'm fine assuming this 6yo battery is done. In that case, get into the battery box to verify what's in there and place an order for a five hundred freakin' dollar battery.

If it fires right up then I get decide if I want to just replace on age and the one day of not quite enough juice to turn it over or not.
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If it’s nearly spring in your neck of the woods you are probably good until September/October

ymmv
 
cowman said:
Flew 1.7hrs today so it should have charged
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FYI: an alternator system basically recovers a good battery back to its original state. It wont "fully" charge a battery like a dedicated charger will especially a battery below its prime.
cowman said:
If it fires right up then I get decide if I want to just replace on age
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While seeing if the aircraft starts will solve your immediate issue, there are OEM capacity checks that will show you the actual health of the battery which you may consider performing if it does start. There are additional tricks that can give you an idea of the health but the cap test is the ticket.

IMO and experience 7 years is the bottom of the scale on battery life and with you at 6 with an unknown service history you may be close enough to warrant a proactive replacement. The cap test mentioned above would verify that.

When you do replace the battery you might want to check/review the electrical system for dirty/loose connections, parasitic drains, excessive voltage drops, etc to give your new battery a good foundation to a long service life. And the most important thing to follow is the OEMs instructions when placing the battery into service. More new batteries are "tweaked" at initial use due to not following these instructions which can take a few years off a batterys life. This is similar to not following the proper breakin instructions for new engines or cylinders.
 
You will find that AGM batteries, like the Concorde, are more tolerant of periods of disuse due to lower self-discharge rates that flooded cell batteries. When replacing a battery, it is a good time to check your alternator/voltage regulator output voltage to ensure it is in the correct range to keep the new battery properly charged. Undercharging or overcharging batteries is a good way to shorten their lifetime, as well as reduce their emergency capacity. I'm changing out a 13 year old (!) Concorde RG-25 battery this annual. It's starting to get marginal. It's pretty common to get at least 6-7 years out of an AGM battery, properly maintained.
 
I own a battery load tester for automotive batteries. I think it's called a carbon-pile tester- it's a big box with jumper-cable style cables to the battery. I crank a knob to increase load and wait for it to beep. One meter shows amp output the other voltage and there's a chart for the current temperature/voltage drop to determine if the battery is good or not. I've always known that as a "load test" not "capacity" but is it basically the same thing?
 
Two different tests.

That test tells you the voltage drop for a given amp draw.

A capacity test is a certain amp draw for a certain time, and check the voltage at that point.

If you fly IFR, you should be doing a capacity test at each annual and if you run the battery down. If you lose your alternator while IMC, you need CAPACITY to keep things working long enough to get to VMC or on the ground.
 
cowman said:
I've always known that as a "load test" not "capacity" but is it basically the same thing?
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No. In general, a load test is based on cranking amps and a capacity test is based on amp/hours. Not the same test. Also you do not want to use automotive test/charge equipment on aircraft batteries as the rates are different and you can damage aviation batteries with auto equipment.
 
Bell206 said:
No. In general, a load test is based on cranking amps and a capacity test is based on amp/hours. Not the same test. Also you do not want to use automotive test/charge equipment on aircraft batteries as the rates are different and you can damage aviation batteries with auto equipment.
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What's different about it? The airplane uses a Chrysler 60-amp alternator after all. Not arguing with you, just unsure how/why there would be a difference.
 
cowman said:
What's different about it? The airplane uses a Chrysler 60-amp alternator after all. Not arguing with you, just unsure how/why there would be a difference.
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How the battery is charged has no bearing on a capacity check or load check. The main difference is a load test checks the stated crank amperage load for as long as you hold the test button, i.e., will it start the car. Capacity checks are not applicable to car batteries.

A capacity test discharges a battery at a set rate (C1) which usually is the battery AH value. The time to discharge the battery to an end voltage of 10v is recorded. Multiply the time length to 10 volts by the OEM conversion factor and you get a capacity percentage.

80-85% is considered good or airworthy. Anything below and you’re on the slippery slope. However, for those aircraft that don’t rely on the aircraft battery as an emergency backup power supply, you can probably go down to 50-60% before changing the battery provided there are no other indicators that show a declining battery health. A capacity check will tell you how long the battery will output useable voltage until dead (11.5v).

A capacity check is also a good indication of the health of your battery whereas a load test just tells you what the battery can do for you at that specific test and not if it can do it again on a regular basis. I've had non-aircraft batteries pass load tests and fail capacity tests. However, never performed a load test on an aircraft battery.
 
Magman said:
Forgive me if you already know this.

If you disconnect the Ground Lead first and install it last you may avoid

unwanted “ excitement”.
Click to expand...

As a young fella in high school auto shop class I was the only one that answered this question correct as everyone else said that the "hot" wire needed to be disconnected first. My dad had taught me a few things as a kid while we tinkered on old cars ...
 
Well at the hangar, confirmed the battery is a Concorde RG-35AXC. Had 12.06V. I tried a load test and it supplied a solid 250 amps and voltage dropped to about 10.5 under load, bouncing back to about 12 after.

I decided to go fly, engine started up immediately no weak crank.

I know ideally it needs a capacity test but with annual only 2 months away maybe I can get by and let the A&P do a proper test.
 
cowman said:
Had 12.06V.
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A healthy battery should have an open-circuit (i.e., unloaded) voltage of 13.2V, that’s 2.2V per cell. Your battery is used up. If you intend to keep flying for the next couple of months, I’d suggest you replace it. Otherwise you’re asking to get stranded somewhere.
 
A typical OCV (open circuit voltage) for a fully charged lead-acid battery is around 12.8-12.9V, An OCV of 12.1 volts would indicate a battery that is charged to less than 50% capacity. This could be because the battery is no longer capable of holding a full charge, or the charging system (alternator and or voltage regulator) is not supplying proper charging voltage, which should be in the 13.8-14.2V range, typically. Part of your troubleshooting should be to measure bus voltage with the engine running (a voltmeter in the accessory socket can be helpful here.) You will want to check the charging output voltage before installing a new battery to avoid ruining a new one if that is the cause of your low battery voltage state. Chronically undercharging your battery will eventually ruin its capacity. It is not uncommon for mechanical voltage regulators to need periodic re-adjustment. Mine was undercharging by about 0.5 V two annuals ago. Readjusted and good as gold now.
 
Bell206 said:
If this is the static voltage with no drain on it, the charge state is less than 25% which will probably give you a 0% capacity test result. Its toast and has the potential to leave you somewhere. Your call and your money, but I'd get a battery coming.
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Plus a weak battery is hard on your starter...
 
So for the logbook…

{Date}
Replaced main battery with Concorde RG-35AXC. Operational check ok.

{Printed Name} Private Pilot {Certificate#}
{Signature}

anything else that needs to go in there?
 
cowman said:
So for the logbook…

{Date}
Replaced main battery with Concorde RG-35AXC. Operational check ok.

{Printed Name} Private Pilot {Certificate#}
{Signature}

anything else that needs to go in there?
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When I did mine I included the battery’s s/n. I also added, “With respect to this preventive maintenance action, this aircraft is approved for return to service.”

Also include airframe hours.
 
cowman said:
anything else that needs to go in there?
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Thats the bare minimum so its good. I prefer to include more info for any future uses. As a note, "function check" is a better term than "operational check" as it implies you're checking only one item and not multiple items. It was taught in my circles that you operationally check an aircraft and function check individual systems.
Removed RG35-AXC, S/N 12345 and installed new Concorde RG-35AXC, S/N: 67890. Torqued and safetied hardware as needed. Function checked battery system no defects noted. 3/9/2023 TT:1234.4 Peter Pilot PP1234567
Half Fast said:
this aircraft is approved for return to service
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FYI: your signature includes this meaning for only the work performed. If you want to include is fine but not required.
 
cowman said:
So for the logbook…

{Date}
Replaced main battery with Concorde RG-35AXC. Operational check ok.

{Printed Name} Private Pilot {Certificate#}
{Signature}

anything else that needs to go in there?
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Doesn't part 43 Appendix A (c) (30) (i) say that it needs to be a private pilot (or higher) who is the owner? Does the word "owner" need to be in there?
 
asicer said:
Doesn't part 43 Appendix A (c) (30) (i)
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Item (30) is for primary category aircraft only. For the remaining appendix items on a normal category aircraft the pilot authorization comes from 43.3(g) as follows:
"the holder of a pilot certificate issued under part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under part 121, 129, or 135 of this chapter."
 
Bell206 said:
Item (30) is for primary category aircraft only. For the remaining appendix items on a normal category aircraft the pilot authorization comes from 43.3(g) as follows:
"the holder of a pilot certificate issued under part 61 may perform preventive maintenance on any aircraft owned or operated by that pilot which is not used under part 121, 129, or 135 of this chapter."
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Ah, right. But the word "owned" is still in that section as well, so I still wonder whether the word "owner" ought to be in the log entry.
 
asicer said:
so I still wonder whether the word "owner" ought to be in the log entry.
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No, as it also includes "operator." Both pilots and mechanics use 43.9 as a reference for maintenance entries and it doesn't require any stipulation (mechanic, owner, operator) of who does the maintenance. Your certificate number will show that: PP vs AP.
 
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asicer said:
Ah, right. But the word "owned" is still in that section as well, so I still wonder whether the word "owner" ought to be in the log entry.
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FYI, it is pretty easy for the FAA to determine who owns the airplane when. If you were the registered owner at the time you signed off on owner completed preventive maintenance, you are good to go. Move on and don’t worry about it.
 
Magman said:
Forgive me if you already know this.

Concordes specify a rather low torque for the terminals.
Click to expand...
I just installed a Concorde battery and the torque value was printed on the battery. I believe it was 70 inch-pounds for mine.
 
You know I have to chuckle about all this. I've probably changed batteries in cars, tractors, and other vehicles dozens if not hundreds of times. I rewired a whole flippin' vehicle once so it's not like any of this sort of thing is unfamiliar. Yet all of the sudden it's an airplane and this simple thing gets 10x more complicated.

Also kinda makes a difference when it's something in my shop 300' from my house where I have almost every tool I'd ever want/need vs a 40min drive to the airport. Then I've got to try to anticipate everything I might need or want and remember to pack it up. Either way thanks for all the info here. Never would have thought to use a torque wrench to hook up a battery, although I did already have one that reads in inch/lbs I bought for rebuilding a transmission.

Changed the ELT battery at the same time as it was due... of the two the ELT was more of a pain and probably took longer.
 
Half Fast said:
WHAT?! You haven't bought a set of tools for the airport yet? Are you ill?
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I don't have a hangar to keep extra stuff in. To be totally clear, my airplane is kept in a HUGE heated hangar that has pretty cheap rent. The problem is it's a community hangar run by the FBO. They also for "liability reasons" don't want maintenance done in the hangar. I went out to do my battery fully prepared to say "ok, tow me out onto the ramp and I'll do it there". Fortunately nobody complained.

This is also the reason I can't just leave a battery minder on it- they move the airplanes around for space in there when the occasional large transient aircraft needs stored. If I needed to I could put a battery charger on it and line guys would disconnect it at the end of the day for me- I used to be able to call our A&P who worked in the hangar next to it and he'd take care of stuff like that :(
 
cowman said:
This is also the reason I can't just leave a battery minder on it
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FYI: if its not a pain you could always disconnect the battery when parked which will reduce its discharge rate vs a battery minder. It does help.
cowman said:
Yet all of the sudden it's an airplane and this simple thing gets 10x more complicated.
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I guess it depends on your point of view. To me helicopters then airplanes are easier/less complex than vehicles, etc. except tractors. Only worked on my vehicles out of necessity which now I pay someone to do that.
 
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