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Best LifePo4 charge controller settings known to man for Maximum Service life and Minimum battery stress!!! 5,000-10,000+ cycles?

toms said:
I have a set of decade old cells that prove just about every statement made in this thread wrong.
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@toms,

Kindly,

Share your decade long logged cell dataset or be quiet.

Or Articulate The Experience In A Quantitative Fashion So We May All Benefit From Your Great Experience.
 
curiouscarbon said:
@toms,

Kindly,

Share your decade long logged cell dataset or be quiet.

Or Articulate The Experience In A Quantitative Fashion So We May All Benefit From Your Great Experience.
Click to expand...

Fair enough, i’ll refrain from further comment until i can gather all the information i have and present it in a simple to follow format.

Anyone that is keen to ask further questions feel free to do so via PM like most people do.
 
full disclosure. im a total noob and i just know toms has many years more experience than myself in this domain. i'm hungry for the knowledge.

of course i can just bulk to 3.6 and cut off at 3.0 or something. seriously appreciate all the input here. just a little desperate to focus it towards numbers ? since even my own experience can be difficult to quantitatively express, if i could even do
 
Will Prowse said:
Yes, lots of data and published literature on this topic:


Starting at page 60:

Quick Excerpt pertaining to temp and calendar aging: "Over time, though, cells degrade and lose capacity in accordance with two different aging phenomena: cycling and calendar aging. It is imperative to understand how these degradation phenomena occur as the loss in capacity results in a loss in vehicle range. Through understanding how these phenomena occur, mitigation efforts can be designed to prevent or lessen their effects. This thesis will focus primarily on studying the effects of calendar aging on commercial LiFePO4 cells. Cells are aged at varying temperatures and states of charge (SOC) to determine the extent of capacity fade and degradation. Additional testing methods are then utilized to attempt to determine which aging phenomena are promoting the losses within the cell. Capacity loss in cells stored at high temperature and fully charged conditions resulted in faster degradation rates. Temperature had the most significant role in the degradation of the cell and then the cell’s SOC. Comparing capacity losses between cells stored at the same temperature, but with different SOCs, found that the cells with higher SOC experienced increased rates of degradation in comparison to their fully discharged counterparts. In addition, storage at high SOC and high temperatures promoted such severe losses that the cells in question were unable to recapture capacity that they had lost reversibly. The primary degradation mode for the cells was the loss of cyclable lithium, and was found to occur under all of the storage conditions. Cells stored at much more severe conditions, though, also demonstrated a loss of active material at the anode. The extent of the loss of the active material was largely predicated on whether or not the cell was stored at fully charged or discharged conditions. Storage of lithium-ion batteries at high temperatures has a dramatic effect on the continual usage of the cells after storage conditions have changed. Despite shifting temperatures or states-of-charge to a lower value, the initial storage conditions leads to increased degradation rates throughout the cell life. Thus, the history of storage for the cell must be also be taken into account when considering losses in capacity."
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This is a very interesting discussion. What about storage in cold environment (0-40 F)? Do the cells degrade like storage in high heat environments or is degradation much less at these cold temps? What voltage does one leave these batteries when being stored in a cold environment? I have seen many say 40-60% SOC but then you have Battle Born who recommends a full charge before long term storage??? So what does the science say, if anything, on this subject?
 
harpo said:
This is a very interesting discussion. What about storage in cold environment (0-40 F)? Do the cells degrade like storage in high heat environments or is degradation much less at these cold temps? What voltage does one leave these batteries when being stored in a cold environment? I have seen many say 40-60% SOC but then you have Battle Born who recommends a full charge before long term storage??? So what does the science say, if anything, on this subject?
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Look closely at the research paper Will linked, SOC seems to show a minor role in the aging process before 20% degradation and actually a protective effect past 20%. 50% and 90% SOC seem to meet at 20% degradation at the same time temperature however plays a major role, generally the lower the better for storage:

1644067391748.png
1644067519202.png


At lower temperatures this model shows longer life at both high and low SOC in storage!

From what I gather from Battleborns recommendation high SOC has little to no effect in aging at normal temperatures but going too low from self discharge is very bad, so its less risky to charge to 100% and it will self discharge a few percent per month on its own. Very low SOC is good for storage but you must watch closely that self discharge doesn't take it down too far, mid SOC 20-80% doesn't really help that much unless the battery are kept very warm all the time.
 
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jharrell said:
Look closely at the research paper Will linked, SOC seems to show a minor role in the aging process before 20% degradation and actually a protective effect past 20%. 50% and 90% SOC seem to meet at 20% degradation at the same time temperature however plays a major role, generally the lower the better for storage:

View attachment 82527
View attachment 82528


At lower temperatures this model shows longer life at both high and low SOC in storage!

From what I gather from Battleborns recommendation high SOC has little to no effect in aging at normal temperatures but going too low from self discharge is very bad, so its less risky to charge to 100% and it will self discharge a few percent per month on its own. Very low SOC is good for storage but you must watch closely that self discharge doesn't take it down too far, mid SOC 20-80% doesn't really help that much unless the battery are kept very warm all the time.
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Thank you jharrell. It took a while for me to decipher the bottom graph which like 3D. I agree that from this data the lower temps are certainly better for storage purposes but the lowest temp there is 25 degrees C or 77 degrees F!
My question dealt with storage temps, for the most part, well below freezing. I don't think the data presented can be extrapolated out to those temperature ranges.
Please correct me if I am misinterpreting this data.
 
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harpo said:
Thank you jharrell. It took a while for me to decipher the bottom graph which like 3D. I agree that from this data the lower temps are certainly better for storage purposes but the lowest temp there is 25 degrees C or 77 degrees F!
My question dealt with storage temps, for the most part, well below freezing. I don't think the data presented can be extrapolated out to those temperature ranges.
Please correct me if I am misinterpreting this data.
Click to expand...
Based on my understanding the aging process is primarily temperature driven and lower is better for storage. That is storing a battery at 0F will have less calendar aging than one stored at 77F given the same SOC. Charging below 0F is not good LFP, storing is actually very good even at 100% SOC, you can see the trend in the 3D plot as temp goes down usable life goes up which should continue well below 0F.

Here is Battleborns take:
 
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toms said:
The reaction in a LiFePO4 cell changes as the C rate changes. If you test at 1C, the results are invalid for 0.5C.

edit: apologies for not going into greater detail - not much time at the moment. It concerns me that there is so much misinformation around especially on this forum regarding LiFePO4.

It’s a shame many of the forums where the exact same discussions were taking place a decade ago are no longer active (and all the people who thought they knew best are now onto their second or third set of cells and unwilling to share their failures online)
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Have you followed T1 Terry by chance?
 
Great information glad to see it consolidated and then dissected it helps me to understand the manufacturers recommendations better and to avoid the practices that are likely to damage my batteries.
I have lithium batteries now in part because of something Will said in one of his tear down videos. He said that the worst lithium batteries generally perform better than the best lead acid. Boy was he right.
I’m thinking that getting too detailed may be an exercise if futility. We don’t have much data from actual use over 20 years. Most of what we have is lab testing that although helpful really doesn’t reflect the the way I can actually use my batteries. 2 years ago the cheapest lifepo4 bank I could for my trailer would have cost over $2500 I got my bank for $1200. In another 2 years will the same thing cost $600? How about 10 years. Will the replacement of batteries become a incidental cost of solar. If so squeaking out 17 years instead of 15 years out of a battery bank seems silly if I will end up upgrading to better technology in ten years. Will the recommendations of today be the recommendations 10 years from now?
No one knows the future so for me I intend to make my batteries serve me. I will use at as close to ideal as I can but if I’m going on a trip I will top off the batteries as close to %100 as I can before I leave. If it’s cold outside I’m not going to turn off the furnace to keep the batteries from going below %10. I bought these batteries to serve me not the other way around. I’m not going to stress trying to hit a target I can’t clearly see. I want to keep my batteries going as long as possible but only if that translates into practical use.
 
curiouscarbon said:
@toms,

Share your decade long logged cell dataset or be quiet.
Click to expand...
What is the obsession with dots going up on a gragh while it charges, dots going down while discharging.

You want graghs there are enough out there in a controlled environment.

It seems if a person beats their chest the loudest with worldly experience and graghs they most certainly got to know something. Damn be experience with different C rates, differing ambient temps, different times of day, different hardware if there's no data logging it must be bogus.

Everyday use running in the background off solar with no hen pecking after many years. How awful. ?

I guess your right nothing useful to offer to some likings. ?‍?
 
curiouscarbon said:
@toms,

Kindly,

Share your decade long logged cell dataset or be quiet.

Or Articulate The Experience In A Quantitative Fashion So We May All Benefit From Your Great Experience.
Click to expand...
No need to be disrespectful. I also respect real life experience over graphs that do "NOT" define how my use is.
 
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Subbed to this thread to learn, not read petty insults towards people who want to learn.
 
grizzzman said:
No need to disrespectful. I also respect real life experience over graphs that do "NOT" define how my use is.
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I respect their real life experience too.

Repeating with no additional details that low-C rate operation is different than high-C rate operation, ok, how is it different?

What is up with the insults towards people trying to learn and make the most of an expensive piece of equipment? That rude junk could get lost from this thread and more people could learn.

Nobody is saying "do not cycle the battery", yet multiple rude posts attacking straw people. That is silly.

This is about optimal system parameters, if I am not mistaken.

Could we please focus on system parameters and lose all that judgey life guidance junk?
 
So what are you're system parameters? What is your system? How are you using it?

That should be stated every time when giving advice so folks can recognize if it's comparable and possibly see how you came to the settings you're using or recommending.

Or atleast put it in a signature to eliminate the guess work so folks will know if it's a 100ah hobby setup or something more. ?
 
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jharrell said:
Based on my understanding the aging process is primarily temperature driven and lower is better for storage. That is storing a battery at 0F will have less calendar aging than one stored at 77F given the same SOC. Charging below 0F is not good LFP, storing is actually very good even at 100% SOC, you can see the trend in the 3D plot as temp goes down usable life goes up which should continue well below 0F.

Here is Battleborns take:
Click to expand...
Thanks for the reply Jharrell.
[/QUOTE]
Yes, I am starting to get a more clear picture of the storage issue from individuals posting on this site. Most studies presented here seem to indicate that cold weather storage will not harm the batteries at all, at least not of any significant nature as long as all loads are disconnected. I actually reached out to BattleBorn several months ago and was told exactly what this video proports. At the time I thought what chemistry variation are they using to recommend this because most back then were saying to keep your batteries above freezing, period, not just for charging purposes but for storage as well. Since that time we have seen studies done and manufacturers such as BB (who has to warranty their product) that cold weather storage below freezing will not harm the cells.
So, at least for now, I am proceeding with that premise until I see objective data that demonstrates otherwise.
 
Please try to stay respectful and constructive guys.

Discuss, make your points, agree or disagree with one another without being rude or disrespectful. We are all here to learn, share, and discuss. Experience and data are both important one does not eliminate the need for the other.
 
harpo said:
Yes, I am starting to get a more clear picture of the storage issue from individuals posting on this site. Most studies presented here seem to indicate that cold weather storage will not harm the batteries at all, at least not of any significant nature as long as all loads are disconnected. I actually reached out to BattleBorn several months ago and was told exactly what this video proports. At the time I thought what chemistry variation are they using to recommend this because most back then were saying to keep your batteries above freezing, period, not just for charging purposes but for storage as well. Since that time we have seen studies done and manufacturers such as BB (who has to warranty their product) that cold weather storage below freezing will not harm the cells.So, at least for now, I am proceeding with that premise until I see objective data that demonstrates otherwise.
Click to expand...
Hi,

confirming, storing or discharging LiFePO4 in cold should not cause damage from the cold alone. of course to avoid cold charging (below freezing)

if the voltage goes too low, that can still cause damage, but it will not be specific to the cold
 
grizzzman said:
Have you followed T1 Terry by chance?
Click to expand...

Funnily enough Terry lives about 50km from me. I don’t agree with all he says and does, but he has installed more RV LiFePO4 systems than anyone i know - and has worked out how to make them last.

He is one that used to frequent forums a lot, now he doesn’t bother trying to help others - he is booked out with work, and has hundreds of systems that have been working for many years. After a while it gets tiresome listening to people that have just got their first system working telling someone that has installed hundreds of systems over the past decade that they don’t know what they are doing.
 
Yes he has been in many forums over the years, The Cruiser forum, Arizona wind and sun, Solar panel talk to name a few. He Is a Moderator at a Australia forum I'm a member of. T1 Lithium keeps him busy. I tried to join this private forum but he said no. He helps people in that forum though.
 
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