Aircraft Battery lifespan, health, and maintenance

nyoung

nyoung

Pre-takeoff checklist
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Aug 5, 2008
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364
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Cary, IL
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Display name:
Nathan young
The Gill G35 installed in my plane is beginning to go (or so I think). Symptoms include slow cranking the last few times I have started the plane. The slow cranking is, of course, exacerbated by winter weather, and a cold soaked plane/battery/hangar. The first start of the day exhibits the symptoms the worst, and subsequent starts while not strong, are good enough.

So that in mind. A few questions...

1. Is the battery starting to go?
2. Is there anyway to resurrect a battery in this condition? I've read that most battery damage is due to plate sulfation, and that once the suflation has hardened, it is not removable.
3. Battery minders. Do they work?
3a. If you use a battery minder in a GA plane, how do you do it? I need to look at the Cherokee electrical schematics, but I think both the external power port, and the cigarette lighter are indirectly connected to the battery (via relay). Does this mean the only way to trickle charge a battery is to open the tail access door, cut the safety wire on the battery case, and charge on the terminals?
4. What kind of lifespan are you getting out of your batteries? Looking back at my logbooks. About every 3 years for me. Not too bad, I guess. Given the inconvenience of getting stuck at an unattended airport, in a lot of ways - a new battery for ~$170 is a great investment.
 
nyoung said:
1. Is the battery starting to go?
Click to expand...
Maybe. Can you load test it?
nyoung said:
2. Is there anyway to resurrect a battery in this condition? I've read that most battery damage is due to plate sulfation, and that once the suflation has hardened, it is not removable.
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Maybe. Depends on how far a battery may be gone.
nyoung said:
3. Battery minders. Do they work?
Click to expand...
Yes
nyoung said:
3a. If you use a battery minder in a GA plane, how do you do it? I need to look at the Cherokee electrical schematics, but I think both the external power port, and the cigarette lighter are indirectly connected to the battery (via relay). Does this mean the only way to trickle charge a battery is to open the tail access door, cut the safety wire on the battery case, and charge on the terminals?
Click to expand...
I have a cable attached to my battery that leads to the cargo compartment. When the plane is in the hangar I run that cable out the cargo door, propping it open so the door does not lay on the cable, and plug it into the battery minder.

nyoung said:
4. What kind of lifespan are you getting out of your batteries? Looking back at my logbooks. About every 3 years for me. Not too bad, I guess. Given the inconvenience of getting stuck at an unattended airport, in a lot of ways - a new battery for ~$170 is a great investment.
Click to expand...
My first battery lasted 3 years, the next one did not make it one year, and the current one is about one year old now and is doing great. Generally, without a desulfinator, 3 years would be a good average. Anything more is bonus. Environment plays a big part in how the battery lasts too. Any soaking at extreme temps can adversely affect the lifespan.
 
I replaced my Gill with a Concord RG-35AXC about 9 months ago and it is great. It cranks way better than the Gill did when it was new. The Gill had spooged a little bit in the battery box. The sealed RG will never do that.
I think we were getting about 3 years from the Gill.
It costs a bit more, but I feel like it won't strand me somewhere remote.
 
Before you go spending money on a battery, take voltage drop readings across the master and battery contactors while cranking the engine. Too many batteries are replaced only to find that old, oxidized contactor points are responsible for poor starting and charging. Been stung that way myself. Some things we learn the hard way.

Dan
 
nyoung said:
The Gill G35 installed in my plane is beginning to go (or so I think). Symptoms include slow cranking the last few times I have started the plane. The slow cranking is, of course, exacerbated by winter weather, and a cold soaked plane/battery/hangar. The first start of the day exhibits the symptoms the worst, and subsequent starts while not strong, are good enough.

So that in mind. A few questions...

1. Is the battery starting to go?
2. Is there anyway to resurrect a battery in this condition? I've read that most battery damage is due to plate sulfation, and that once the suflation has hardened, it is not removable.
3. Battery minders. Do they work?
3a. If you use a battery minder in a GA plane, how do you do it? I need to look at the Cherokee electrical schematics, but I think both the external power port, and the cigarette lighter are indirectly connected to the battery (via relay). Does this mean the only way to trickle charge a battery is to open the tail access door, cut the safety wire on the battery case, and charge on the terminals?
4. What kind of lifespan are you getting out of your batteries? Looking back at my logbooks. About every 3 years for me. Not too bad, I guess. Given the inconvenience of getting stuck at an unattended airport, in a lot of ways - a new battery for ~$170 is a great investment.
Click to expand...


Any time you have suspect of a battery failure, the ICAs for the battery must be complied with. If it fails that test the battery must be replaced.
 
1. If you have a clock (digital or otherwise) then you have a built-in way of slow-charging the battery. That clock is direct-connected to the battery through a small value (3 amps is quite common) breaker or fuse RIGHT AT THE BATTERY. You can run a wire from the clock to a panel-mounted connector to do a remote charge. Limit the charge current to an amp or so.

2. A common 2.5mm dc power plug (see Jameco page 126) will replace the cigarette lighter (and who smokes in airplanes these days) and let you do a "quick plug" from your charger.

3. "But a 2.5mm plug isn't MilSpec..." . Daddy taught me a long time ago to make it right, then make it legal. YMMV.

4. No, a trickle charger is a sure fire way to kill your battery. Just like the rest of us, the battery loves exercise. Let it build up to 13.6 or so, then self-discharge slowly down to 12.6 or so, then slowly back up to 13.6, and so on indefinitely or until you want to go flying again.

Jim
 
weirdjim said:
1. If you have a clock (digital or otherwise) then you have a built-in way of slow-charging the battery. That clock is direct-connected to the battery through a small value (3 amps is quite common) breaker or fuse RIGHT AT THE BATTERY. You can run a wire from the clock to a panel-mounted connector to do a remote charge. Limit the charge current to an amp or so.
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Some aircraft electronic clocks use an internal battery to maintain the time when the master is off but many are wired as you stated. But since there's a good chance that the leads of a battery charger might short out or that the charger might produce more than a couple amps when the battery is fairly discharged, you're risking the inline fuse by charging through it. I think a much better choice would be a separate fused connection directly to the battery side of the master contactor.

4. No, a trickle charger is a sure fire way to kill your battery. Just like the rest of us, the battery loves exercise. Let it build up to 13.6 or so, then self-discharge slowly down to 12.6 or so, then slowly back up to 13.6, and so on indefinitely or until you want to go flying again.

Jim
Click to expand...
The main problem with most "trickle chargers" is that they aren't regulated at all and will eventually overcharge the battery if left connected too long. There are some on the market that can be left on indefinitely without overcharging but unless they are of the "smart" variety with temperature compensation the final regulated voltage is likely to be too high or too low at least some of the unless you're in a heated hangar. The "Battery Minder" is one that could be operated continuously but even with that one I'd only run it for several days each month.
 
Someone should make a plot of average environmental temp vs battery life.
 
My nine year old Concord AXC 35 now lives on a desulfator wtih a 40 mah charge rate set at 13.4V. I retired it out of fear even though it just passed the 90% discharge test, per Concord's ICAWs.

The one in my airplane lives on the same regimen, with the bus sent for 13.5V and the combination 1 A charger, 13.4 float desulfator on all the time in the hangar. I got 9 years out of the last one.

I lent this battery to the local full time CFI whoe Archer battery died. He was conducting a lesson 10 minutes later- it cranked like no tomorrow. He replaced his battery with a new AXC 35 and I gave him the old one on condition that it lives on a "Battery Minder" in his hangar.

Continued desulfation and a lowish (not 14.2V) charge ceiling to prevent loss of H2O are the key to a long battery life.
 
gismo said:
I think a much better choice would be a separate fused connection directly to the battery side of the master contactor.




The main problem with most "trickle chargers" is that they aren't regulated at all and will eventually overcharge the battery if left connected too long.
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No, I respectfully disagree. I'm not in a place where I can quote you chapter and verse, but my rememberance of the FAR is that you get ONE tap directly to the battery and it has to be limited to either 3 or 5 amps. If you already have a keep-alive or clock breaker is that everything has to come off of that one tap. The simple answer to a charger short is to put a an inline low-current quick-blow fuse between the charger and the relatively large tap fuse/breaker.

If you will reread my post, I specifically said that trickle charge is the easiest way to kill a battery. Concorde engineers specifically recommended to me (when I wrote my Kitplanes article on AGM battery charging) that the charge-discharge-charge-discharge cycle was the way to extend battery life to the maximum. And that it could be done continuously without any problems.

Jim
 
bbchien said:
My nine year old Concord AXC 35 now lives on a desulfator wtih a 40 mah charge rate set at 13.4V. I retired it out of fear even though it just passed the 90% discharge test, per Concord's ICAWs.

.
Click to expand...


Care to share make and model of charger/sulfatebuster?

Jim
 
http://www.northerntool.com/shop/tools/product_200332201_200332201

I now have seven of them, one on the standby elect. start 7KW generator, one on each car, one on the moped, one on the backup A/C battery in the hangar, one on the airplane.

There is an aircraft version designed I think for GILL. Much more expensive. This one is/has been compatible with Concorde's battery specs (charging and bus voltages). The A/C version, however IS temperature compensated.
 
I tried the Northern Tool 1.3A one posted, so far I think it has paid off. Motorcycle, mower, a/c batteries all have lasted longer than previously. I move the tender from battery to battery every 2 weeks all year long, and try to be dutiful about monitoring fluid levels.
 
When my 20 y.o. daughter brings the 1997 Camry home, it lives plugged in. Anything to prevent premature battery replacment. I ran the OEM battery to 2004, replaced hers with an Interstate Battery Co. Middle Level replacement, and have my fingers crossed.
 
It's during hot weather that trickle charging can diminish the lifetime of a lead-acid battery.
 
Let'sgoflying! said:
I tried the Northern Tool 1.3A one posted, so far I think it has paid off. Motorcycle, mower, a/c batteries all have lasted longer than previously. I move the tender from battery to battery every 2 weeks all year long, and try to be dutiful about monitoring fluid levels.
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I agree. On the tiny Yuasa battery on the moped I have to meticulously fill the cells each fall.
 
weirdjim said:
No, I respectfully disagree. I'm not in a place where I can quote you chapter and verse, but my rememberance of the FAR is that you get ONE tap directly to the battery and it has to be limited to either 3 or 5 amps. If you already have a keep-alive or clock breaker is that everything has to come off of that one tap. The simple answer to a charger short is to put a an inline low-current quick-blow fuse between the charger and the relatively large tap fuse/breaker.
Click to expand...

I'd like to see a reference on this as my airplane has two connections, one fused at 1A and one through a 10A CB feeding a ground power avionics switch (something I've seen on lots of airplanes including two I've owned).

If you will reread my post, I specifically said that trickle charge is the easiest way to kill a battery. Concorde engineers specifically recommended to me (when I wrote my Kitplanes article on AGM battery charging) that the charge-discharge-charge-discharge cycle was the way to extend battery life to the maximum. And that it could be done continuously without any problems.
Click to expand...
I wasn't disagreeing with your statement that trickle chargers are bad for batteries, I was simply suggesting the mechanism.

BTW while some "exercise" is good for a lead acid battery, battery life is to a great extent inversely proportional to the average percent of discharge (IOW the deeper the discharge the shorter the life).
 
gismo said:
I'd like to see a reference on this as my airplane has two connections, one fused at 1A and one through a 10A CB feeding a ground power avionics switch (something I've seen on lots of airplanes including two I've owned)..
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FAR 23.2361:

(a) There must be a master switch arrangement to allow ready disconnection of each electric power source from power distribution systems, except as provided in paragraph (b) of this section. The point of disconnection must be adjacent to the sources controlled by the switch arrangement. If separate switches are incorporated into the master switch arrangement, a means must be provided for the switch arrangement to be operated by one hand with a single movement.


(b) Load circuits may be connected so that they remain energized when the master switch is open, if the circuits are isolated, or physically shielded, to prevent their igniting flammable fluids or vapors that might be liberated by the leakage or rupture of any flammable fluid system; and
(1) The circuits are required for continued operation of the engine; or

(2) The circuits are protected by circuit protective devices with a rating of five amperes or less adjacent to the electric power source.

(3) In addition, two or more circuits installed in accordance with the requirements of paragraph (b)(2) of this section must not be used to supply a load of more than five amperes.
​

(c) The master switch or its controls must be so installed that the switch is easily discernible and accessible to a crewmember.
 
weirdjim said:
FAR 23.2361:

(a) There must be a master switch arrangement to allow ready disconnection of each electric power source from power distribution systems, except as provided in paragraph (b) of this section. The point of disconnection must be adjacent to the sources controlled by the switch arrangement. If separate switches are incorporated into the master switch arrangement, a means must be provided for the switch arrangement to be operated by one hand with a single movement.


(b) Load circuits may be connected so that they remain energized when the master switch is open, if the circuits are isolated, or physically shielded, to prevent their igniting flammable fluids or vapors that might be liberated by the leakage or rupture of any flammable fluid system; and
(1) The circuits are required for continued operation of the engine; or

(2) The circuits are protected by circuit protective devices with a rating of five amperes or less adjacent to the electric power source.

(3) In addition, two or more circuits installed in accordance with the requirements of paragraph (b)(2) of this section must not be used to supply a load of more than five amperes.
​
(c) The master switch or its controls must be so installed that the switch is easily discernible and accessible to a crewmember.
Click to expand...

You threw me a curve with the "23.2361" (the actual subpart is 23.1361) but in any case my airplane (like many flying today) was certified under CAR 3 which had no such requirement. If I needed to comply I could split the loads so that the highest CB required was 5A.

And anyway I don't see anything that would preclude multiple "hot" feeds as long as each is limited to no more than 5A and none are paralleled to supply a load greater than a 5A CB can handle.
 
gismo said:
You threw me a curve with the "23.2361" (the actual subpart is 23.1361) but in any case my airplane (like many flying today) was certified under CAR 3 which had no such requirement. If I needed to comply I could split the loads so that the highest CB required was 5A.

And anyway I don't see anything that would preclude multiple "hot" feeds as long as each is limited to no more than 5A and none are paralleled to supply a load greater than a 5A CB can handle.
Click to expand...

So far as I can remember, CAR 3 had this rule too, but I don't have a copy of that antique reg in my library.

You can have multiple hot feeds, but according to section (3) they cannot ADD UP to more than five amps all told.

Jim
 
Dosn't matter for a bird in part 91 service. The pigtail is removeable equipment and is signed off as such at annual.

However I can't emphasize enough that the flyer needs to get the pigtail with the inline fuse. The older ones don't have that....you can't just get out and disconnect the burning line.....
 
weirdjim said:
So far as I can remember, CAR 3 had this rule too, but I don't have a copy of that antique reg in my library.

You can have multiple hot feeds, but according to section (3) they cannot ADD UP to more than five amps all told.

Jim
Click to expand...
My read of subpart 3 is that you cannot use two 5A breakers to supply a single load which exceeds what a 5A breaker could handle. I don't see anything that limits the total with multiple CBs/circuits feeding separate loads.
 
gismo said:
My read of subpart 3 is that you cannot use two 5A breakers to supply a single load which exceeds what a 5A breaker could handle. I don't see anything that limits the total with multiple CBs/circuits feeding separate loads.
Click to expand...

Then your read contradicts what the PMIs in both the San Diego and Sacramento FSDOs preach. :cheerswine:
 
Down here along the hot Gulf Coast, 2 years is about right for any type of vehicular battery.

As least with my aircraft, it's easy enough to hand prop it if I get stuck at some little airport in the boondocks... Kind of a corollary to the saying "don't drive any vehicle that you're not able to push"...
 
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