Shelf life limit on uninstalled CYPRES 1 battery pack?

[ryoder 1,381]

Couldn't find the answer at cypres-usa.com, so I've sent them an email.
Anyone know if there is a limit?

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[Hooknswoop 19]

CYPRES 1 works with a battery that is calculated to last for approx. two years or approx. 500 jumps. The battery is a high-energy density type, with long life, low self-discharge and has a long shelf life (approximately 3 years), as long as it is stored in a cool, dry location (below 68°F). It consists of two round cells, and does not contain heavy metals.
Each battery which has been installed in CYPRES 1 has to be replaced after 2 years at the latest. In case that the rig or CYPRES 1 will be out of use the battery should be removed and disposed of after 2 years to prevent possible damage. The battery can be replaced by the user, however, the procedure is tricky and demands considerable attention to detail.
The 2-year maximum period does not start until the battery is installed for the first time. After installing a battery that has been stored for more than 6 months, it is recommended that the CYPRES 1 be turned on and off 4 times in succession to “activate” the battery.
The battery's current voltage is displayed during each activation cycle. After the unit has been switched on, there is a self-test routine during which numbers beginning with 9999 count down rapidly toward 0. The countdown is interrupted for approx. three seconds at a value somewhere between 6900 and 5700. This interruption indicates battery charge. For example, suspension of the countdown at 6300 means that the actual battery voltage is approx. 6.3 volts.
When the self-test routine is repeated several times within a short interval, the displayed battery voltage will not be constant. This is normal and has nothing to do with the technical components of CYPRES 1 but rather, properties of the battery. Typically, the voltage displayed during a second or third self-test cycle will be lower than the voltage displayed during initial activation. With further self-test cycles, voltage will rise again.
If the unit has not been used for a long time, the battery voltage shown on the display during the initial self-test can appear to be rather low. However, the voltage displayed does not indicate a discharged battery but it is merely due to certain characteristics of the battery: The absence of an electric current over a prolonged period will result in the build-up of an internal protective layer which will minimize self-discharge. This layer can be removed by simply switching the unit on and off a couple of times. You will then see that the battery voltage shown during self-test will rise again.
Battery failure or low battery voltage will be detected by CYPRES 1. At the end of the self-test cycle, CYPRES 1 will stop with an error display of 8999 or 8998 and will not assume operating mode. This indicates that the energy supply of the battery is no longer within operational limits.

Derek

[Gary73 8]

I asked SSK about this myself a while back. They said that a battery pack has a shelf life of three years after the manufacture date that's stamped on one side in MMYY format.

"Extraordinary claims require extraordinary evidence." - Carl Sagan

[riggerpaul 1]

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I asked SSK about this myself a while back. They said that a battery pack has a shelf life of three years after the manufacture date that's stamped on one side in MMYY format.

Just to be PAINFULLY clear, the 3 year shelf life is completely separate from the 2 year or 500 jump service life.

After being on the shelf for a full 3 year shelf life you will still get a full service life of 2 years or 500 jumps out of your CYPRES battery.

So a CYPRES battery might be in service up to as long as 5 years past the date stamp.

But another question comes to mind.

Is a battery that has been on the shelf for 4 years good for 1 more in service? Or does Airtec expect us to toss out a battery that has been on the shelf for 3 years and a day?

I've never seen any discussion of this, and I suppose it would be pretty unusual to have a 4 year old never installed CYPRES battery. I know I've never had one on the shelf for more than a few months.

If SSK is listening, can you answer these questions?

[ryoder 1,381]

Quote

But another question comes to mind.

Is a battery that has been on the shelf for 4 years good for 1 more in service? Or does Airtec expect us to toss out a battery that has been on the shelf for 3 years and a day?

I've never seen any discussion of this, and I suppose it would be pretty unusual to have a 4 year old never installed CYPRES battery. I know I've never had one on the shelf for more than a few months.

If SSK is listening, can you answer these questions?

SSK sent me an answer this morning:

Quote

CYPRES 1 batteries have a shelf life of three years as long as they're stored in a cool dry place. If 03/07 is stamped on the battery they can wait to be installed until 03/10.

So I would say in answer to your question, if the batteries are older than 36 months, they cannot be used.

"There are only three things of value: younger women, faster airplanes, and bigger crocodiles" - Arthur Jones.

[riggerpaul 1]

Yes, that's the predictable answer.

But if an unused battery today has an expected service life of 2 years, it seems unlikely that its service life tomorrow should be zero. At least, not because of the physics of the battery.

It is clear that Airtec implies the battery physics allows for a 5 year total usable life. You can find a battery in a rig that is up to five years past the battery date stamp without anything being wrong at all. Even according to the way the documentation is currently written.

Why should that same battery only be good for 3 years if it had never been used at all?

I believe that the predictable answer is not about battery physics, but is about how hard it is to describe and talk about.

I believe that according to the physics of the battery, they could just as well have said "the battery has an absolute life of 5 years, and a maximum service life of 2 years or 500 jumps".

That wouldn't have the problem that an unused 3 year plus 1 day old battery would have to be tossed.

[377 20]

One reassuring data point is that a well known rigger had a Cypres fire at WFFC a few years ago. His battery was waaay out of date, by years according to what I heard, but everything worked OK. I worked with Li batteries in the implantable heart defibrillator field, another mission critical application. Li batts have amazing shelf lives, far far beyond what conservative manufacturers specify. I think everyone should follow Aietec's battery replacement procedures, but it is nice to know that a Cypres with an out of date battery has a good chance of working if it passes the startup test. A helicopter mfr did an informal study in South America where component overhauls are frequently faked with the equivalent of pencil packing. They found that aside from electrical actuators using brush type DC motors, most components appeared to function OK way beyond TBO times. Be safe, replace AAD batts as mandated by the mfr. Don't ever bet your life on being lucky.

2018 marks half a century as a skydiver. Trained by the late Perry Stevens D-51 in 1968.

[ficus 0]

Quote

Yes, that's the predictable answer.

But if an unused battery today has an expected service life of 2 years, it seems unlikely that its service life tomorrow should be zero. At least, not because of the physics of the battery.

This seems like a simple variation on "the Cypres times out in a month, should I pack it?" What are you going to write on the packing data card if you put a 3 years + 1 day battery in Cypres and close it up?

[riggerpaul 1]

Hi Ficus, nice to see you in the forum.

I agree with the other poster that the legal way to interpret what Airtec has said is to toss the battery after 3 years on the shelf.

If Airtec had worded it the way I suggested, I would record the DOM of the battery on the packing data card and it would time out when either 5 years since DOM, 2 years in service, or 500 jumps had occurred, which ever comes first. We already have to apply similar limitations when we are packing a PD reserve. They can become unairworthy at different times depending on what has happened to them.

But your question points out that we commonly return rigs to service with insufficient information to guarantee that the rules have been followed. Nobody tells me how many jumps they've made on their CYPRES battery. If it has been more than 500, I cannot legally return it to service. We have people at our DZ that make more than 500 jumps in the possible 2 year service life of a CYPRES battery. The units may still work, but technically, they should not be returned to service until the battery has been replaced.

I want to say that I understand this is a pretty meaningless discussion in the first place because it is unlikely that anybody has a 3 year old battery on the shelf. It gets even less interesting as more of the CYPRES AADs reach end-of-life. The CYPRES2 has no jump count limitation, and we riggers in the field don't change the batteries.