How long do your batteries last?

[ArrowFlyer86]

I had a 2yr old Gill battery that died on me last Thursday.

Due to a mix of holiday travel, sub-zero temps and perpetual LIFR fog I only managed to fly the plane 3h in the last 30 days. That's the lowest amount of time I've ever flown over a 1 month interval with the exception of when it's in annual.

The battery was nearly dead. Enough juice to power lights/G5 for preflight checks but not enough to crank the engine and turn the prop, just generate a low pitch groan from the starter. I replaced it with a Concorde RG25.

Question: Should the battery have lasted longer than 2y?
I fly it 150-200h a year and keep it in a heated hangar at ~60F, so it's not subjected to sitting in cold temps. But I also did absolutely zero maintenance on the battery (e.g., no connection to a battery charger while plane is in the hangar).

 

[Gary Ward]

Keeping the water level up inside is required maintenance. I top mine off twice a year and my Gill is going on 6 years now.
Twice in the last 6 years I left the master on and I found it dead the next day. I recharged it immediately and both times it recovered but I am sure I shortened it's life some by letting it go dead.

I fly 2-7 days a week so plenty of recharging. If I am down for more than 7 days I will put it on the charger over night. Then take the charger off after 24 hrs. Use a battery minder made for my battery.

 

[brien23]

I love Concorde RG25 Battery replacement, people throw them out at 2 to 3 years. I remove the plastic seal open each cell and add a little water only enough to cover the cell and suck out anything above that or it will bubble out and make a mess, recharge and put in my lawn mower and get another 3 or 4 years of use, great batteries. I do not recommend you do that and put it back in your plane as Concorde or Gill do not recommend putting water in their sealed batteries. As to Flooded cell battery, normal care and they last 6 to 8 years problem is people do not add water that goes away with normal use, I have tested to Gill capacity test of batteries over 8 years old and still pass, great Batteries. The peak charging voltage for Gill or Concorde batteries is 2.3 to 2.36 volts per cell, if your charge voltage is higher than that you lose water out of your battery and shorten the life of it.

 

[ArrowFlyer86]

These are good benchmarks.

I never topped it off with water -- whoops. TBH, I didn't even know the Gill wasn't a sealed battery until we pulled it on Thursday.
I don't recall ever getting mx paperwork or an owners manual from the shop that dropped the Gill in outlining proper care. But that's totally on me for not doing research about what they'd installed.
Good to know they can last substantially longer if properly cared for. Lesson learned.

 

[GeorgeC]

My plane lives outside and its Odyssey is coming up on 3 years. Every now and then, I plug in a self-powered desulfator, but maybe that's the MMO of batteries. Is your voltage regulator setpoint at the correct voltage?

 

[ArrowFlyer86]

My plane lives outside and its Odyssey is coming up on 3 years. Every now and then, I plug in a self-powered desulfator, but maybe that's the MMO of batteries. Is your voltage regulator setpoint at the correct voltage?

That I do not know, nor do I know how to verify.

 

[GeorgeC]

Quick and dirty: plug in a cigarette lighter voltmeter from your local discount tool importer and see what it says with your engine running and alternator on.

This chart is from Concorde, but I'm sure Gill has something similar:

 

[eman1200]

concorde came with my plane in 2017. I just replaced it with another one a few months ago. I could tell the cranking was getting a little weak and figured it served it's purpose well and was due for a new one. that also included an A&P leaving the master, on draining the battery, recharging it and it lasting another 2 years.

 

[ArrowFlyer86]

concorde came with my plane in 2017. I just replaced it with another one a few months ago. I could tell the cranking was getting a little weak and figured it served it's purpose well and was due for a new one. that also included an A&P leaving the master, on draining the battery, recharging it and it lasting another 2 years.

Thanks, another good benchmark.
My battery lost charge last year when in a 7 week annual. The A&P realized it the day I was getting the plane back. He hooked it up to a charger and when it was good enough he gave me the plane back. After I got it running I didn't have any issue with it again for 8 months, until it died last wk.

 

[Bell206]

Should the battery have lasted longer than 2y?

No reason why you shouldn't get 7+ years out of your battery. Main culprits are electrical system condition and excessive discharges without a full recharge with an appropriate charger. A close second is lack of yearly maintenance

However, may still be able to save this battery provided you get it to a place with a Gill acceptable charger.

This was one of the first things we'd look at with my new owner-assist customers as it is very common to get only 2-3 years out of their batteries which they thought was normal. The Gill manual has all the details you need.

 

[GMascelli]

Recently replaced my eight year old Concorde with another of the same, a Concorde RG35 AXC. My plane is hangared and I do keep a battery specific BatteryMinder on it 24/7 when it's in the hangar.

 

[chemgeek]

I gave up on flooded cell batteries long ago. Sealed AGM batteries (i.e. Concorde) are very tolerant of neglect and don't need service (water replenishment). AGM batteries have very low self-discharge rates, so leaving them for a month or so will not result in any issues. To get long life out of any battery, ensure that your charging system is set to the correct voltage to prevent over- or under-charging. I changed out my Concorde RG-25 last year when it couldn't pass a capacity test--11 years old. (I think 5-7 years is more routinely realistic.) I don't do anything for my Concorde batteries except try to fly at least once a month during the winter season when it isn't always practical to fly regularly.

The one caveat about AGM batteries is if you let them go flat (leave the master on overnight) they will become permanently sulfated if you don't recharge them properly within 24 hours or so. Flooded cell batteries are a little more tolerant of deep discharge.

 

[dmspilot]

Gill makes sealed batteries as well. Mine was 5 years old when I sold the plane.

 

[Pinecone]

From reading several forums, Concordes last longer than Gills, but the newer Gills seem to be better.

No matter what, if you have power available, get the proper Battery Minder for your battery and use it. It will increase the life of the battery by keeping it charged, but not over charged, and desulfating it at times.

 

[Checkout_my_Six]

6-7 yrs.....I've replaced (2) Gills and (2) Concorde RG35s....make sure your charging system isn't over charging your battery and fly your plane at least once a month and it will last. No minder or any other device is needed.

 

[Chip Sylverne]

Before you take a battery out of service, any battery, download a copy Concorde's ISM and read the conditioning and maintenance charging procedures. Then grab a constant current DC power supply off Amazon, like $70. I have saved several lead acid batteries, 8ncluding my very expensive heavy equipment d series and restored my 5 year old 35rxc back to 100% measured capacity.

 

[idahoflier]

I replaced my Gill last fall at 6+ years. It was still functioning fine, but given it's age I didn't want to get stuck somewhere. I try to fly every 1 - 2 weeks in the winter and weekly in the warmer months. Engine is always preheated in the winter for easy starts. I also have no parasitic load on the battery in between flights like the clock...

 

[MRC01]

Funny you would ask. The Gill G-243 in my plane is 8 years old now, tied down outside, flown regularly and gets a handful of freezing starts each winter. It's finally dying, slow crank if it's been sitting more than a week (which rarely happens). No battery minder, and the only parasitic load is a clock, but I do check the fluid levels annually. System voltage reads between 28.1 and 28.5 during normal engine operation. I think 8 years is pretty good and am looking to buy another one.

 

[ArrowFlyer86]

I replaced my Gill last fall at 6+ years. It was still functioning fine, but given it's age I didn't want to get stuck somewhere. I try to fly every 1 - 2 weeks in the winter and weekly in the warmer months. Engine is always preheated in the winter for easy starts. I also have no parasitic load on the battery in between flights like the clock...

How can you tell if you have a "parasitic" load while it's sitting? I've always wondered about my plane but none of the accessories come to mind. (Clock is wind-up.)

Is there an easy test to see if the battery is slowly being used by something even when the master is off?

 

[Bell206]

Is there an easy test to see if the battery is slowly being used by something even when the master is off?

Yes. Get a digital VOM and set the leads and range to AMPS (10A). Disconnect the negative battery cable and connect the black VOM lead to the cable end and connect the red VOM lead to the neg battery terminal. If there is a parasitic drain it will indicate on the VOM. In general, any reading above .05 amps needs to be looked at further. If you need pictures there are a number of Youtube vids on how to perform a drain test. No different than a car.

But in addition to parasitic drain checks, you can also perform voltage drop checks on both the positive and ground side of the electrical system to identify other issues that may be affecting your battery health. And so on.

 

[Pinecone]

Realize that just because the battery will turn the engine over does not mean it is OK.

Most aircraft and batteries require a capacity check at annual, and if the actual AH capacity it less than 80% of rated, the battery should be replaced.

 

[Brad W]

I learned the hard (er...expensive) way a long time ago with non-aviation toys such as boats and campers.... the lesson about battery self-discharge rates. I replaced more batteries than I'd want to admit before I finally learned my lesson...either put a maintainer on it or a mechanical disconnect at the battery post and use it.
When I park a toy, my goal is that it won't sit a day in storage without one of those two things

Is a battery disconnect switch a thing that is allowed and/or done on aircraft? I've only ever rented so even though I feel like I should know this, I don't

I suppose IF the master relay does disconnect 100% of the loads then it is in effect the same thing...but in my experience there's almost always some sort of parasitic draw on these things.

 

[Bell206]

Is a battery disconnect switch a thing that is allowed and/or done on aircraft?

Yes you can and yes it has been. But only for very specific requirements and this is not one of them. Otherwise the disconnect switch just becomes another item that won't be maintained.

there's almost always some sort of parasitic draw on these things.

Yes, but to a point. If you're losing batteries over it the drain is too high no matter what the "toy." Unfortunately most people rather plug in a battery maintainer then fix the problem which still takes years off a battery's life.

 

[Brad W]

Yes you can and yes it has been. But only for very specific requirements and this is not one of them. Otherwise the disconnect switch just becomes another item that won't be maintained.

Yes, but to a point. If you're losing batteries over it the drain is too high no matter what the "toy." Unfortunately most people rather plug in a battery maintainer then fix the problem which still takes years off a battery's life.

I understand and agree with your first point.... something I sortof already knew...
It's all the difference between 'proper', and not

but the second point yeah, you're right...kind of, under ideal circumstances (such as putting it to bed near 100% soc) But even something as minute as a clock or to maintain a memory can be significant enough.
now all of this is non-aviation knowledge and experience, but I have no reason to understand that aviation lead acid batteries are any different.
I've seen self-discharge rates for lead acid batteries stated to be in the range of 3% to 5% per month. That's a bare post battery.
a typical rule of thumb is 50% state of charge is about the bottom end of 'ok' for a standard starting battery. Real world I'd imagine is probably a little less than that...and of course true deep cycle batteries are designed for much lower....
Still, I've ruined a lot of batteries by letting them drop below that 50%-ish state...even just one time can affect the total capacity of that battery in my experience

if you run the battery down for whatever reason... trouble starting the engine and cranking it for a while.... and take it down to something pretty low say 55% SOC. ..then put the "toy" to bed...and that ends up being a month or more self discharge can take it down to the danger zone...you don't need any parasitic draws no matter how tiny helping out in that effort!

 

[bkspero]

My prior RG-25 lasted only 2 years. It had been installed by the local shop and they charged it before installation. A while later I spoke with an accommodating engineer at Concorde and he speculated that the battery had been discharging in inventory somewhere for a long time prior to going into my plane (hence the need for charging), and that was the reason for its short life. I replaced it with another RG25 that I bought from Aircraft Spruce. It had a production date the month before (a small sticker on the battery) and was fully charged when I got it. That one is going strong near the end of year 6.

The moral of the story is to take care that the "new" battery going into your plane hasn't been sitting around for many months discharging and possibly sulfating.

 

[Bell206]

I've seen self-discharge rates for lead acid batteries stated to be in the range of 3% to 5% per month. That's a bare post battery.

Except batteries also have shelf lifes and storage limits. Parasitic drain issues are usually part of an in-service battery and not a storage or shelf life issue.

So if I understand your post correctly, you are storing various equipment for extended times with the batteries installed, and then at some point in the future you pull it out and find the battery kaput?

Storing batteries is a whole different matter and usually has its own section in a manual complete with the storage/shelf life protocols. No lead acid can remain unused to extended periods without damage.

 

[bkspero]

Quick and dirty: plug in a cigarette lighter voltmeter from your local discount tool importer and see what it says with your engine running and alternator on.

This chart is from Concorde, but I'm sure Gill has something similar:

I wonder about this chart. My battery is in the engine compartment ahead of the firewall and behind the rear baffle. Anyone know what the temperature in the area usually is when the battery is charging? I don't. Charging voltage when the engine is on is about 13.9-14.0 volts (corresponding to 87-113F). Not implausible. Big difference between that and 13.5-13.75 V for above 113F, though. And I wouldn't be surprised if the temperature of the battery is that hot in the summer when flying at low altitude.

What happens where the battery is in the tail of the plane? I'd guess that the temperature there is close to the outside temperature, and it would vary with both time of the year and altitude. How could one adapt for that variation?

 

[Bell206]

How could one adapt for that variation?

If you wanted the full potential life out of the battery, you would adjust the voltage regulator based on the average battery temps for the area. Same for batteries installed in the engine compartment. If you want the fullest life adjust accordingly, however, most simply adjust to what the Cessna or Piper manual says and run with it. How much life does it add? Depends on how much the temp swings and how the battery is treated. Unfortunately, what usually happens is the battery is damaged in other ways over its life and cancels out any advantages. However, if you live in an area with a large average temp change between summer and winter and fly your aircraft regularly, you may want to look at a summer and winter setting which I have done in the past for various airplanes and helicopters.

 

[Brad W]

Except batteries also have shelf lifes and storage limits. Parasitic drain issues are usually part of an in-service battery and not a storage or shelf life issue.

So if I understand your post correctly, you are storing various equipment for extended times with the batteries installed, and then at some point in the future you pull it out and find the battery kaput?

Storing batteries is a whole different matter and usually has its own section in a manual complete with the storage/shelf life protocols. No lead acid can remain unused to extended periods without damage.

yep, that's pretty much it...well past tense.... pretty much what I used to do. Put it away for a month, maybe with a slightly depleted battery, and it might end up being much longer before I'd use it again. Even then I was always careful to turn everything off, but still with wires connected there's a load that hits in addition to self-discharge.
I ultimately figured out that a mechanical disconnect helps

 

[Mikey52]

So does a battery charger/conditioner.

 

[texasclouds]

3-3.5 yrs roughly on my Concord. It was struggling to turn the prop last summer and when it got cold it was barely getting the job done cold. I put a new one in for peace mind.