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LiFePo4 Shelf Life?

CoolWill

Solar Addict
Joined
Sep 21, 2022
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I haven't traditionally been a fan of lithium batteries as off grid storage simply due to the relative "newness" of the technology. Also because of local availability of lead batteries if I need a quick replacement.

But I do like the deep discharge and high capacity of these newer cells and so I've thought about buying a set to get my feet wet. I'd need 16 to make a battery for my 48 volt system. So if I bought a few at a time, will the age difference between them be a problem at assembly? In other words, how long can I keep different cells before it's too late to put them into a battery together?
 
So if I bought a few at a time, will the age difference between them be a problem at assembly? In other words, how long can I keep different cells before it's too late to put them into a battery together?
I don't see any point in doing that. Age should not be that significant esp. over a few months, but you could end up with different batches or even versions of the cells that will have different capacities.

Also, as cells seem to be coming down in price then surely, if you can't afford to buy 16 in one go, just put the money in a savings account and buy them all in one batch in 6 month's time. Then you save on delivery charges too :)
 

HOW TO STORE LIFEPO4 BATTERIES?​

How do I store my lithium battery? A question we receive from our customers on a daily basis, especially in the Winter season. The answer depends on the temperature you are storing the batteries in and the period of time. Here’s a summary of how to store your LiFePO4 battery:
  • Recommended storage temperature: -5 to +35°C (23 to 95 °F)
  • Storage up to 1 month: -20 to +60°C (4 to 140 °F)
  • Storage up to 3 month: -10 to +35°C (14 to 95 °F)
  • Extended storage time: +15 to +35°C (59 to 95 °F)
It is highly recommended to store lithium batteries indoors during the off-season. It is also recommended to store LiFePO4 batteries at about a 50% state of charge (SOC) or higher. If batteries are stored for long periods of time, cycle the batteries at least once every 6 months. Do not store batteries that are discharged. Canbat.com https://www.canbat.com/how-to-store-lifepo4-batteries/

If you store them at the same conditions as the ones you are ordering later it should not cause an issue.

Added: Yes this is discussing batteries but batteries are made up of cells so same factors should apply. I posted this because people may be looking for info on storing their LFP batteries which many people using RV's or at a recreation or remote work site do.
 
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HOW TO STORE LIFEPO4 BATTERIES?​

How do I store my lithium battery? A question we receive from our customers on a daily basis, especially in the Winter season. The answer depends on the temperature you are storing the batteries in and the period of time. Here’s a summary of how to store your LiFePO4 battery:
  • Recommended storage temperature: -5 to +35°C (23 to 95 °F)
  • Storage up to 1 month: -20 to +60°C (4 to 140 °F)
  • Storage up to 3 month: -10 to +35°C (14 to 95 °F)
  • Extended storage time: +15 to +35°C (59 to 95 °F)
It is highly recommended to store lithium batteries indoors during the off-season. It is also recommended to store LiFePO4 batteries at about a 50% state of charge (SOC) or higher. If batteries are stored for long periods of time, cycle the batteries at least once every 6 months. Do not store batteries that are discharged. Canbat.com

If you store them at the same conditions as the ones you are ordering later it should not cause an issue.

Not helpful. OP is talking about cells.

I don't see any point in doing that. Age should not be that significant esp. over a few months, but you could end up with different batches or even versions of the cells that will have different capacities.

Also, as cells seem to be coming down in price then surely, if you can't afford to buy 16 in one go, just put the money in a savings account and buy them all in one batch in 6 month's time. Then you save on delivery charges too :)

I'm with this. Stash the money and save up rather than buying piecemeal. Better to make one big purchase and don't forget to get a spare cell too.

With regards to storage. Most cell datasheets have storage information. Worth consulting.

Most cells are received in the 30-50% SoC range, so all you need to do is store them in reasonably controlled ambient conditions, check them every few months and note that the voltage has changed little and note if you have any outliers that are losing voltage faster than any others. They will be your trouble cells. If any cell falls below 3.20V, immediately charge to > 3.25V.
 
Not helpful. OP is talking about cells.



I'm with this. Stash the money and save up rather than buying piecemeal. Better to make one big purchase and don't forget to get a spare cell too.

With regards to storage. Most cell datasheets have storage information. Worth consulting.

Most cells are received in the 30-50% SoC range, so all you need to do is store them in reasonably controlled ambient conditions, check them every few months and note that the voltage has changed little and note if you have any outliers that are losing voltage faster than any others. They will be your trouble cells. If any cell falls below 3.20V, immediately charge to > 3.25V.
Last time I looked batteries are made up of cells and all you did is repeat what I posted as your own opinion.

Have a great day!
 
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Lat time I looked batteries are made up of cells and all you did is repeat what I posted as your own opinion.

Have a great day!

Where did you recommend the OP consult the cell data sheets?

The statements I made are not opinion. They are factual based on 1) personal experience, 2) years of activity on this site observing the experience of others, 3) direct support functions for others, 4) reading cell datasheets from multiple manufacturers and 5) reading scientific papers on a multitude of LFP cell behaviors in various conditions/applications.

I'm guessing you have a lot to offer and could be a good resource for this forum. You and I agree wholeheartedly on where wind falls in one's resources. However, I request that you consider that your expertise in one area may not translate to expertise in another even if it's similar. With regards to LFP, you may want to take a backseat to other more experienced members,.

Please... for the love of all that is holy, do not simply copy and paste generalized, seemingly related information (tangentially so at best) from MARKETING sources. That doesn't benefit anyone.
 
Where did you recommend the OP consult the cell data sheets?

The statements I made are not opinion. They are factual based on 1) personal experience, 2) years of activity on this site observing the experience of others, 3) direct support functions for others, 4) reading cell datasheets from multiple manufacturers and 5) reading scientific papers on a multitude of LFP cell behaviors in various conditions/applications.

I'm guessing you have a lot to offer and could be a good resource for this forum. You and I agree wholeheartedly on where wind falls in one's resources. However, I request that you consider that your expertise in one area may not translate to expertise in another even if it's similar. With regards to LFP, you may want to take a backseat to other more experienced members,.

Please... for the love of all that is holy, do not simply copy and paste generalized, seemingly related information (tangentially so at best) from MARKETING sources. That doesn't benefit anyone.

Are you a moderator of this site?

I am new here but if this is the attitude of the members or moderators here I can leave and share my 20+ years of experience with off grid solar power under real life conditions some where else. I am not here to get in to a pissing contest with you or anyone!
 
Are you a moderator of this site?

No. I left that life behind. Moderators are identified when they post.

I am new here but if this is the attitude of the members or moderators here I can leave and share my 20+ years of experience with off grid solar power under real life conditions some where else. I am not here to get in to a pissing contest with you or anyone!

I have expressed my personal opinion as to what is most beneficial for the forum members. I indicated I believe you have a lot to offer, and I identified an area in which we completely agree. I am not presenting any piss for contest. I suspect we are of similar age, and our prostates do not place us as "highly competitive" in that arena. I tried to convey that copy/pastes from marketing sources is not helpful to anyone, and it is often irrelevant.

I would encourage you to stay and contribute in your area of expertise, which appears to off-grid living - doing more with less, etc. Consider that you may have only a beginner's understanding of LFP batteries (high experience folks don't quote marketing sources), and you might stand to learn more than you can contribute on that subject, especially when it comes to building your own.

You have a nice day too.
 
No. I left that life behind. Moderators are identified when they post.



I have expressed my personal opinion as to what is most beneficial for the forum members. I indicated I believe you have a lot to offer, and I identified an area in which we completely agree. I am not presenting any piss for contest. I suspect we are of similar age, and our prostates do not place us as "highly competitive" in that arena. I tried to convey that copy/pastes from marketing sources is not helpful to anyone, and it is often irrelevant.

I would encourage you to stay and contribute in your area of expertise, which appears to off-grid living - doing more with less, etc. Consider that you may have only a beginner's understanding of LFP batteries (high experience folks don't quote marketing sources), and you might stand to learn more than you can contribute on that subject, especially when it comes to building your own.

You have a nice day too.
OK, what is your real life experience using and living with solar and batteries of any kind?

Impress me with your years living with just solar and batteries and doing the maintenance and installation for those systems.

Are you a solar or heat pump installer looking for customers?

The group says it is DIY solar so I assume most people here are not engineers and are looking for small system help but maybe I am wrong!
 
OK, what is your real life experience using and living with solar and batteries of any kind?
Impress me with your years living with just solar and batteries and doing the maintenance and installation for those systems.


39 acres of vacant land 6500' elevation in ENE AZ. System in 40' shipping container. 2X 5th wheels powered by the system. Can run 2X RV A/C for about 6-8 hours per day if needed.

Everything was placed on this land by me. Every drilled hole, threaded fastener, etc., has been installed by me. System is maintained by me over the last 4 years, part time.

1697128180578.png
Battery build:


Are you a solar or heat pump installer looking for customers?

Nope. Nor am I a Youtuber looking for traffic.

The group says it is DIY solar so I assume most people here are not engineers and are looking for small system help but maybe I am wrong!

I am, though my engineering degree is not applicable to DIY solar aside from a problem-solving foundation.

I will defer to you on your off-grid living expertise. As you can see, I'm running A/C off my system, but I built up to that. My goal is not to do more with less, but to keep my wife happy with this shit while trying to optimize efficiency behind the scene. I *might* have more experience than you in certain areas. Maybe you defer to others on Lithium battery experience, regardless of size? :)
 

39 acres of vacant land 6500' elevation in ENE AZ. System in 40' shipping container. 2X 5th wheels powered by the system. Can run 2X RV A/C for about 6-8 hours per day if needed.

Everything was placed on this land by me. Every drilled hole, threaded fastener, etc., has been installed by me. System is maintained by me over the last 4 years, part time.

View attachment 171979
Battery build:




Nope. Nor am I a Youtuber looking for traffic.



I am, though my engineering degree is not applicable to DIY solar aside from a problem-solving foundation.

I will defer to you on your off-grid living expertise. As you can see, I'm running A/C off my system, but I built up to that. My goal is not to do more with less, but to keep my wife happy with this shit while trying to optimize efficiency behind the scene. I *might* have more experience than you in certain areas. Maybe you defer to others on Lithium battery experience, regardless of size? :)
We all start somewhere!

I started in an RV/camper like yours but winters were too cold and not designed for temperature extremes.

I can relate to the wife part. I dumped mine when I went off grid. Also too expensive to keep :ROFLMAO:

You are welcome to point out something in my posts that may not be accurate on the engineering level but you came off to me as rude and trolling.

I am always happy to answer questions, correct info and learn from other people as long as they are polite.

As to youtube channels my work stands for itself and no need to advertise it these days. I was the first off grid channel on Youtube helping people back when the housing market crashed and millions lost homes and I am proud of that work but that is a story for another day.

Hope to see your progress on that homestead!
 
I am not here to get in to a pissing contest with you or anyone!
but then provokes @sunshine_eggo with...
OK, what is your real life experience using and living with solar and batteries of any kind?
Impress me with your years living with just solar...
eh? :confused:


As to youtube channels my work stands for itself and no need to advertise it these days.
.. but has signed up with the name @Solarcabin Channel and profile says "I have several books and cabin plans available for free or low cost on my website."


And personally I find it distasteful when you say...
I can relate to the wife part. I dumped mine when I went off grid. Also too expensive to keep :ROFLMAO:
Sorry, but this is 2023... we (females) are not objects to be "dumped" or "be kept", FFS :mad:?‍♀️

If that is your attitude then please do...
I can leave and share my 20+ years of experience with off grid solar power under real life conditions some where else
 
The total expense for the cells isn't that great on the whole, I'm just not the type to drop a couple grand on something I'm not sure of. Spreading the cost out a hundred here a two hundred there makes me psychologically more amiable to it. Even saving the money makes me anxious once the day comes because I start doing the ol' "That money is better spent elsewhere..." But that's a personal hang up. I'll try to put that together.
 
but then provokes @sunshine_eggo with...

eh? :confused:



.. but has signed up with the name @Solarcabin Channel and profile says "I have several books and cabin plans available for free or low cost on my website."


And personally I find it distasteful when you say...

Sorry, but this is 2023... we (females) are not objects to be "dumped" or "be kept", FFS :mad:?‍♀️

If that is your attitude then please do...
If only more women thought that way hence why I dumped her because she expected to just be kept and not work or help.

Or maybe I should say traded in the older broken model for 2 younger girlfriends?

Yes, I have books and cabin designs that have been used by many people to go off grid. This is a site for DIY solar when I looked and people looking for ideas might want a plan that actually works under real life off grid conditions.

You try to have a better day!
 
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but then provokes @sunshine_eggo with...

eh? :confused:



.. but has signed up with the name @Solarcabin Channel and profile says "I have several books and cabin plans available for free or low cost on my website."


And personally I find it distasteful when you say...

Sorry, but this is 2023... we (females) are not objects to be "dumped" or "be kept", FFS :mad:?‍♀️

If that is your attitude then please do...
I'm sure women never talk about men that way.?
 
The total expense for the cells isn't that great on the whole, I'm just not the type to drop a couple grand on something I'm not sure of. Spreading the cost out a hundred here a two hundred there makes me psychologically more amiable to it. Even saving the money makes me anxious once the day comes because I start doing the ol' "That money is better spent elsewhere..." But that's a personal hang up. I'll try to put that together.

The benefits of purchasing all at once are far greater than any mental benefit from piecemeal acquisition. You are MUCH more likely to get cells from the same lot that have highly similar characteristics across the board that will contribute to more stable operation, fewer problems and likely optimized cycle life. No, you're not risking major issues buying onesie-twosie, but it's almost certain you'll get cells with variations in self-discharge rate that may make maintaining a top balance difficult.
 
We all start somewhere!

You're likely not intending it, but that's no less condescending than your interpretation of my response. I could argue that because my system progressed from something smaller than yours and is already larger and more capable, that my experience is more valuable than yours.

I have literally tested several hundred Lithium cells, built multiple LFP batteries, configured multiple BMS of varying complexity, tested many thousands of NiMH cells and built several hundred batteries for hybrid vehicles, should I have responded with:

"We all start somewhere!"

I don't need your validation in any way. My efforts have already eclipsed yours for the intended goal. I will eventually power my comfortable, forever retirement home. I don't see that you have anything to offer in that regard, BUT I don't dismiss by suggesting you have nothing to offer on a smaller scale or for someone with different goals.

I started in an RV/camper like yours but winters were too cold and not designed for temperature extremes.

Temperatures run from single to triple digits. I intend to be 100% electric with gas/propane generator backup.

I can relate to the wife part. I dumped mine when I went off grid. Also too expensive to keep :ROFLMAO:

Helps if you get the right one. My wife and I both have a practice marriage under our belt, but we have it mostly figured out after 25 years.

You are welcome to point out something in my posts that may not be accurate on the engineering level but you came off to me as rude and trolling.

I have something of a disclaimer in my signature:

1697134556866.png

It's more about being blunt than deliberately offensive.


I am always happy to answer questions, correct info and learn from other people as long as they are polite.

That's a two way street my friend... :D

As to youtube channels my work stands for itself and no need to advertise it these days. I was the first off grid channel on Youtube helping people back when the housing market crashed and millions lost homes and I am proud of that work but that is a story for another day.

Except that you've chosen to use a username and include information that ties you to those potential revenue sources. I chose a silly avatar and username and provide no links to anything that might earn me a single red cent, and only a handful here know my first name. A couple have even met me in person. My primary revenue comes from working as an engineer in aviation as well as a side hustle that involves replacing hybrid batteries.

I have spent HOURS helping folks as far away as Lithuania configuring and optimizing their system. I have made personal phone calls to help people out of an emergency situation. I even made a "house call" to someone in my area. I have been offered payment for services, but I have declined EVERY time... EXCEPT... One kind forum member gifted me their V1 Starlink dish after they had already upgraded to the V2 dish. I offered to pay them for it, but they insisted... and I'm damn tired of DSL. That is the sum total of the financial benefit of over three years and >20,000 posts.

Objectively, you might be interpreted as using this as a vehicle to generate revenue where one would be hard pressed to find evidence (beyond the above) that I use this site for financial gain.

Hope to see your progress on that homestead!

Nah. You're not interested in seeing someone go off grid with a full system, home and the creature comforts. You're too tough for that! :) (mean it. not being a dick)
 
You're likely not intending it, but that's no less condescending than your interpretation of my response. I could argue that because my system progressed from something smaller than yours and is already larger and more capable, that my experience is more valuable than yours.

I have literally tested several hundred Lithium cells, built multiple LFP batteries, configured multiple BMS of varying complexity, tested many thousands of NiMH cells and built several hundred batteries for hybrid vehicles, should I have responded with:

"We all start somewhere!"

I don't need your validation in any way. My efforts have already eclipsed yours for the intended goal. I will eventually power my comfortable, forever retirement home. I don't see that you have anything to offer in that regard, BUT I don't dismiss by suggesting you have nothing to offer on a smaller scale or for someone with different goals.



Temperatures run from single to triple digits. I intend to be 100% electric with gas/propane generator backup.



Helps if you get the right one. My wife and I both have a practice marriage under our belt, but we have it mostly figured out after 25 years.



I have something of a disclaimer in my signature:

View attachment 171997

It's more about being blunt than deliberately offensive.




That's a two way street my friend... :D



Except that you've chosen to use a username and include information that ties you to those potential revenue sources. I chose a silly avatar and username and provide no links to anything that might earn me a single red cent, and only a handful here know my first name. A couple have even met me in person. My primary revenue comes from working as an engineer in aviation as well as a side hustle that involves replacing hybrid batteries.

I have spent HOURS helping folks as far away as Lithuania configuring and optimizing their system. I have made personal phone calls to help people out of an emergency situation. I even made a "house call" to someone in my area. I have been offered payment for services, but I have declined EVERY time... EXCEPT... One kind forum member gifted me their V1 Starlink dish after they had already upgraded to the V2 dish. I offered to pay them for it, but they insisted... and I'm damn tired of DSL. That is the sum total of the financial benefit of over three years and >20,000 posts.

Objectively, you might be interpreted as using this as a vehicle to generate revenue where one would be hard pressed to find evidence (beyond the above) that I use this site for financial gain.



Nah. You're not interested in seeing someone go off grid with a full system, home and the creature comforts. You're too tough for that! :) (mean it. not being a dick)
Wow, that chip on your shoulder must be getting pretty heavy friend!

Pointing to your reputation for insults and rudeness does not exactly help your case :cool:

"but to keep my wife happy with this shit"

That probably explains the chip.

This is going way off topic and my work helping people go off grid is well known.

If you want some free plans to build a cabin and get out of that RV just let me know and happy to help!
 
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