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

[sunshine_eggo]

so would 3.45 not hit 90% i noticed you said with your 280ah cells. you only got to 64% SOC.
were running 120ah cells

I have always indicated an extended absorption time for 3.40/3.45. I was illustrating the difference between having an absorption phase vs. not.

it seems according to your guys comments [thanks by the way] that having lower CC CV voltage while altho good, will keep it in absorption mode longer which is bad [, while having a higher voltage which is bad for max service life but will keep it in absorption shorter which is good for max service life [doesnt seem to be a choice to shut off absorption in the mpps]

. . . good, ol dammed if you do dammed if dont situation. lol . ?

No. Absorption at peak voltage (3.55-3.65) for extended periods is unnecessary/bad. Getting to near full at 3.40-3.45, absorption is necessary and also occurs at a lower current - lower voltage + lower current = better.

what would you guys recomend for max service life 3.4 3.45 or 3.5v per cell while allowing enough voltage to reach 90% SOC with in typical 5.5 FL sun day [we have between 1.5 and 2k coming in [depending on our system[were making multiple] which is a total of 8.2kw and 11kw with a average consumption during sun time of 500w so minus are consumption exactly we will have exactly 5kw of sun to charge the 5kw pack. in the alotted 5-6 of Fl sun hours and we can always cut back consumption during sun hours to allow more power to make into the batteries. .

Fast charge with generator: 3.55-3.65
Slow charge with solar/grid: 3.45
Float: 3.40

The reality is that if you have good quality cells, you don't abuse them, and make an effort to use them will within their ratings, you should expect good service life - likely longer than spec.

 

[Horsefly]

You can't do what the subject requests on a pure voltage basis. Here are your options:

Fast charging to full: 3.55-3.65V/cell - 30 minute absorption time.
Slow charging/longer cycle life (98%+ charge): 3.45V/cell - 4+ hour absorption time.
Float (95%+): 3.4V/cell

The slow charging method is less stressful to the cells and should improve cycle life while still attaining near 100% charge.

Depending on the load, you want to disconnect around 3.1V/cell to stay in the 10-20% range.

The only real way to accomplish a 10-90% operating range is to get a quality battery monitor and synchronize it to 100% charge.

Discharge until it indicates 10% - that's your low voltage threshold.

Charge until it indicates 90% - that's your absorption voltage AND your tail current, i.e., you terminate charging once it's attained that voltage and current has dropped below the observed value - your charging hardware must be programmed accordingly.

Although there is absolutely nothing wrong with what @sunshine_eggo has suggested, I'll just throw in a slight change to the charge profile I've arrived at: Bulk/Absorption to 3.5V/cell (kinda between his fast and slow charging), 30-60 minute absorption time. Truth is the current drops to almost nothing before that time. Then float at 3.35V/cell. I like the SoC way of getting to a voltage on the high end and low end, but the voltages can vary significantly for charge, discharge, and resting. Makes it hard to find the perfect spot, but the goal does have merit.

Here is the knee curves.
View attachment 82268

I kinda wish people would not keep posting these curves and the SoC table. It is easy to trust it too much. The thing that needs to be said is that these voltages in the graphs and in the table appear to be resting voltages, i.e. some hour or more after any charging or discharging, and with nothing going into our out of the cells. If the pack is being charged at even a relatively small current (0.2C or more) the voltages will be higher, and if it is being discharged it will be lower. I appreciate @Maintenance guy is trying to help, but it is easy for someone new to this to put too much faith into these voltages, when they shouldn't.

 

[Sojourner1]

I'll bet 6 years ago lfp cell/ batteries cost more than what you guys are paying now so if you think I wouldn't like longevity,, I do but at the same time I want to live off them not coddle them. I believe with my use pattern I'll still get 10 plus years with everyday use. I don't coddle my bank either, it will pull loads of 75 -225a from a few minutes to hours depending what I'm using.
It's amusing to see "rumors" of longevity of 20 years. I've read of a few lfp off grid setup going on 10-12+ years now.

My system has been a set it and forget. Just amazing to see lfp at 25% SOC and still use microwave (150a) for 5 minutes and still not hit low volt disconnect from the inverter which is set at 12.0v. ?

 

[Go2Guy]

Although there is absolutely nothing wrong with what @sunshine_eggo has suggested, I'll just throw in a slight change to the charge profile I've arrived at: Bulk/Absorption to 3.5V/cell (kinda between his fast and slow charging), 30-60 minute absorption time. Truth is the current drops to almost nothing before that time. Then float at 3.35V/cell. I like the SoC way of getting to a voltage on the high end and low end, but the voltages can vary significantly for charge, discharge, and resting. Makes it hard to find the perfect spot, but the goal does have merit.


I kinda wish people would not keep posting these curves and the SoC table. It is easy to trust it too much. The thing that needs to be said is that these voltages in the graphs and in the table appear to be resting voltages, i.e. some hour or more after any charging or discharging, and with nothing going into our out of the cells. If the pack is being charged at even a relatively small current (0.2C or more) the voltages will be higher, and if it is being discharged it will be lower. I appreciate @Maintenance guy is trying to help, but it is easy for someone new to this to put too much faith into these voltages, when they shouldn't.

I guess the big issue, is we as a solar community have no choice BUT to set these numbers on these controllers,. . .
Bulk/Absorb
Float
Low voltage cut off

. . .. I know its not the ideal way to manage it BUT its the only way that 90% of currently available and affordable charge controllers handle these battery packs. Eventually i would like to get a columb meter, BUT it seems even if i get one ,it will give me SOC numbers which is great . But IT still not control the system since its the above settings handled by the charge controllers that controller the pack charges , I know its not the ideal way to do it BUT its the only way most of have, so my reall goal is to have the best humanely possible numbers that i can plug into these settings to get this battery to last as long as physically possible. what you mentioned about resting voltages is also a huge issue even with lead acid[ been dealing with this for years] , if your using a battery back there is no way of actually telling what the pack is at. . since loaded and charging number are always so different from resting numbers. . but even when i was just setting up the mpp i had no choice but to set such "in load" and "in charge" numbers when it ask what voltage like like when to connect to grid when battery gets to low and what voltage to connect back to battery, with out a SOC table how would one even go about setting this number, is the number i even put right when under load or charge??? I dont even know I set to switch to grid when at 25.5 roughly 20% according to a SOC table it back to go back to battery @ 26.5 roughly 70% according to a table is this ideal ???? not even sure but i have no choice to but to set these numbers if i want to use this feature SBU[solar battery utitility] SMH lol

 

[Will Prowse]

Really good discussion, but at 20 years, calendar aging will probably be what kills lifepo4. Cycle bandwidth modification probably won't help much. Solar cycling is typically at very low C rates and typically does not hang out at high SOC, so you should get 7,000-10,000 daily cycles without issue.

But keep in mind you can still use the batteries at this point, they will just be at a reduced capacity. Batteries are getting cheaper though, so I wouldn't stress it. Charge to 100% and down to 0%. Use the full capacity before you lose it to calendar aging regardless.

You can reduce calendar aging rate by keeping your batteries in a cool environment.

 

[sunshine_eggo]

Really good discussion, but at 20 years, calendar aging will probably be what kills lifepo4. Cycle bandwidth modification probably won't help much. Solar cycling is typically at very low C rates and typically does not hang out at high SOC, so you should get 7,000-10,000 daily cycles without issue.

But keep in mind you can still use the batteries at this point, they will just be at a reduced capacity. Batteries are getting cheaper though, so I wouldn't stress it. Charge to 100% and down to 0%. Use the full capacity before you lose it to calendar aging regardless.

You can reduce calendar aging rating by keeping your batteries in a cool environment.

Do you have any data on calendar aging affects? HEV spec NiMH is about 1%/year, but I've not found anything for LFP or other flavors. I ran some calcs in another thread assuming 0.5%/year and that shaved a couple years off a 10-12 year cycle life computation.

 

[Will Prowse]

Yes, lots of data and published literature on this topic:

https://www.mdpi.com/1996-1073/14/6/1732/pdf

Starting at page 60:

https://uwspace.uwaterloo.ca/bitstream/handle/10012/12177/Catton_John.pdf

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."

 

[Will Prowse]

For cycle life estimations on cell data sheets, try to find the c rate. Typically, it is higher or equal to .5-2C. So I would not use these estimations when LiFePO4 is being used for solar storage systems.

Most of these cycle life estimations are for use with EV application at higher c rates with constant shallow cycling for regenerative braking and repeated high surge discharges for running inductive loads.

 

[Will Prowse]

So in my opinion, charge LiFePO4 to 100%, and discharge to 0%. Use the capacity while you still have it. Daily cycle for solar is not strenuous on the iron phosphate lattice much at all. Keep your batteries cool and balance charge (keep at high SOC to trigger balance circuit) every 4 months or so, and they should last a long time.

If you want a conservative absorption figure, Victron recommends 3.525V. I now set my absorption to 3.6V, and set BMS HVD for 3.65V to avoid stressing the FET's.

 

[Go2Guy]

Alright guys, I just want to say I am thankfull for every ones input. . I really really appreciate it. . so far after ABSORBING all this great information [pun intended lol] this is what i have came up with for others who are looking for a quick reference on settings for maximum service life, i again i really appreciate all the input. if any one thinks i got something wrong or wants to amend what i wrote please let me know. my goal is to just have a single source of optimal settings for max service life. .

BEST SOLAR SETTINGS [SO FAR] FOR MAXIMUM LIFE 5,000-10,000+ cycle life

PREFACE The Best settings possible are actually to run from 14%-90% SOC and this has little to due with voltage [besides staying out of the voltage knee] however this is not possible with out a columb meter,or even better a charge controller that operates off of this principle. . BUT most charge controllers are designed for lead acid and being that the case we have to enter in voltage numbers numbers, so even tho this is not the ideal way to go about it, its the only way for most of us with cheaper and/or older charge controllers. . SO these are best voltage numbers possible known by the great contributors of this group to achieve the maximum service life possible and put the batteries under as little stress as possible.

BULK/ADSORB 3.45-3.52 [heavily debated] but universally agreed no higher than 3.52 for max service life [3.52 is what victron recommends for max service life
[lower voltage= slower charge times IE [C rate] which is Good but potentially longer in absorb phase which is Bad]
[Higher voltage=faster charge times which is more stressful on cells, BUT less time in absorb phase which is good ] 3.5v-3.52 seems to be a good compromise fast and slow charge times NOTE: Lower voltages means charge rate will be reduced at high SOC and it will be harder to reach 100%. which is great if your shooting for less than 90% state of charge. !!!IMPORTANT NOTE: While the above mentioned data is recommended for minimum stress on the cells it is important that the voltage you set activates your BMS, to keep your cells balanced, if not your BMS becomes useless and will never actually balance , most BMS activate around 3.4 VERIFY at what voltage your BMS activates at . if you are not sure, it just may be better to higher voltage to ensure that its activated[Will Prowse goes all the way to 3.6v OR another option is to keep an eye on it and make sure the cells stay balanced.

FLOAT 3.35
3.35 volts is a good float voltage for high reserve capacity and minimal cell
degradation [3.35 is not really debated if maximum service life is the goal 3.4 if you want a little bit more reserve. Also 3.4 is recommended by many OEMS, however according to some data at 3.35 the cell is not really in a state of stress while anything higher than this it is. . your choice a little bit more conservative or a little bit more reserve ]

CUT OFF 3.1V [but a more ideal verifying the cut off voltage is is to run down battery pack under average load you will be running and then take note of what cell voltage drops off first, once the first cell drops off in voltage , measure the total pack voltage and set low cut off voltage to that measured total pack voltage.
NOTE: In certain high load situations you may get get voltage drop causing the system to "cut off" and shut down under high load even if its not necessarily towards the end of your desired capacity. . , if this is the cause. you may have to set the cut off lower voltage. . 3.1 is a conservative number 3.0-2.9 is recommended for high load situations, but remember this post is all about having the data to make educated choices if your goal is maximum service life and achieving a balance between functionality and maximum service life

OTHER NOTES:
Temperature-"""storage at high State of charge and high temperatures promoted such severe losses that the cells in question were unable to recapture capacity that they had lost reversibly""".DO NOT STORE IN HIGH SOC especially in HIGH HEAT, i dont have all the data yet but it seems operating under 32F or over 100F could/will causes damage[especially under 32] as a good precaution in short if your not comfortable the batteries are not comfortable, [this is a super generic but a safe conservative recommendation] As solutions to this conundrum people will run thermostat controlled heat pads and heat blankets for the winter [search the forum] and use water tanks/pads or ac for high temp operation [search the forum] .

STORAGE, batteries should be stored at about 40% SOC if going to be in storage for long periods of time. . high SOC storage causes premature cell degradation

DON'T BE AFRAID to use the battery at 100% if needed, calendar aging [definition, loss of capacity due to time alone] [thanks will for this input] also plays a role in long term degradation so if even if you baby these cells to the max, with old age you will still loose capacity. .so these numbers above are to baby the cells, but it is perfectly okay to use full 100% soc when you need it , when taken into consideration that the effect that calendar aging has on the battery. Its is a balance between the battery is loosing capacity on its own due to aging and you babying or not babying the cells , because of calendar aging some say who cares and just use it at 100% at all times , however that defeats the purpose of this post of attempting achieve maximum service life. . but it definitely doesn't hurt to use it when you really need it. .
Balance--(run batteries to a high SOC to trigger a good balance on your BMS 4 months or so, -as a maintenance. think of as a equalization ]

A grate read by Joey on taking care of your cells https://diysolarforum.com/resources/how-charging-works-in-the-context-of-lfp-batteries.233/download
_________________________________________________________

 

[Will Prowse]

I have also mentioned this with battery engineers who are trying to find ways to improve LiFePO4, and they have always agreed with my conclusion. I would say that it is consistent with the literature. Keep the batteries cool, and you shouldn't have any problem running LiFePO4 for a few decades.

Many people reference cobalt based lithium ion studies that pertain to high c rate cycling, and the cycling bandwidth modifications make a massive difference. But you do not have these same issues with LiFePO4. There is higher degradation rates at high SOC for LiFePO4, but it is not nearly as high as the cobalt based chemistries. The iron phosphate lattice is extremely stable, and it can handle the high SOC without issue. If you store at high temperature (see studies above), and at high SOC, you will have premature failure. But no one here is storing at 60 degrees C. Or cycling at high c rates all day.

Even NMC is used with tesla powerwalls and those should not last nearly as long as LiFePO4, but when used with solar, can last a very long time regardless. Those packs do modify their cycling bandwidth, so they can have higher cycle life ratings. But when using LiFePO4, I would not worry about it at all. Just cycle it to 100%.

 

[Will Prowse]

Alright guys, I just want to say thankfull for every ones input. . I really really appreciate. . so far after ABSORBINGall this great information [pun intended lol] this is what i have came up with for others who are looking for a quick reference on settings for maxium service life, i again i really appreciate all the input. if any one things i got something wrong or wants to amend what i wrote please let me know. my goal is to just have a single source of optimal settings for max service life. .

____________________________________________________________
BEST SOLAR SETTINGS [SO FAR] FOR MAXIMUM LIFE 5000%+ cycle life

BULK/ADSORB 3.45-3.52 [heavily debated] but universally agreed no higher than 3.52 for max service life [3.52 is what victron recomends for max service life
[lower voltage= slower charge times IE [C rate] which is Good but potentially longer in absorb phase which is Bad]
[Higher voltage=faster charge times which is more stressful on cells, BUT less time in absorb phase which is good ] 3.5v-3.52 seems to be a good compromise fast and slow charge times NOTE: Lower voltages means charge rate will be reduced at high SOC. which great of your shooting for less than 90% state of charge. but will make harder to hit 100%

FLOAT 3.35 [not really debated if maximum service life is the goal 3.4 if you want a little bit more reserve. ]

CUT OFF 3.1V [but more ideal to run down battery pack under average load you will be running and then take note of what cell voltage drops off first, once it does, measure the total pack voltage and set low cut off voltage to that measured total pack voltage.

_________________________________________________________

You need to ensure that the absorption voltage you choose is higher than the balancing trigger voltage of your BMS. Very important. If you do not look this up, you will have issues. Probably best to charge to 3.6V and you will be good to go. Usually they are triggered at 3.4V, but you need to ensure that this is being triggered every time your pack is at high SOC.

3.4V for float is good, and recommended by multiple manufacturers.

3.1 is a little conservative. I would go for 3.0-2.7V. It is great for LVD, especially at high C rates. Even 3.0V is a little too conservative on my large packs. If you set your inverter to 3V, you will not have an issue with BMS LVD being triggered.

 

[Go2Guy]

You need to ensure that the absorption voltage you choose is higher than the balancing trigger voltage of your BMS. Very important. If you do not look this up, you will have issues. Probably best to charge to 3.6V and you will be good to go. Usually they are triggered at 3.4V, but you need to ensure that this is being triggered every time your pack is at high SOC.

3.4V for float is good, and recommended by multiple manufacturers.

3.1 is a little conservative. I would go for 3.0-2.9V. It is great for LVD, especially at high C rates. Even 3.0V is a little too conservative on my large packs. If you set your inverter to 3V, you will not have an issue with BMS LVD being triggered.

Thanks Will, I will add this these notes. .

 

[curiouscarbon]

tossing one more thing in the mix..

calendar aging and cycle aging both are temperature dependent

General LiFePO4 Degradation vs Temperature

Concerned about your LiFePO4 batteries ♨️Overheating♨️ or ❄️Freezing❄️and losing ability to hold charge due to operating temperature? This is a research paper that carries out charging and discharging at set temperatures, and evaluating the...

diysolarforum.com

just an additional reference, that studies the cycle aging vs temperature angle.

remember, this paper only did 100 cycles, keep that in mind when interpreting degradation rate!

keeping the LiFePO4 cell cool should reduce *both* cycle aging and calendar aging

edit to clarify paper's methodology​

 

[Browneye]

What is a recommendation for a RV in storage over summer where interior temperatures are liable to exceed 100. It's rare, but happens. My guess is battery temp won't climb that high, but without a 30A shorepower connection you would have to run the generator for air conditioning. And who wants to run AC in a stored unit?

My intention is to store the pack at about 70% SOC. So my float voltage on the SCC is 13.2/3.3/cell. After 3.55/cell absorption the controller goes into float and the pack discharges to about 70% over a few days with parasitic loads - primarily the LPG sniffer.

Is it recommended to completely disconnect the battery from loads? Leave it at 50-70%?

I then have a settings parameter file I can load into the SCC for active use, with more normal/higher charging and float voltages.

 

[HRTKD]

What is a recommendation for a RV in storage over summer where interior temperatures are liable to exceed 100. It's rare, but happens. My guess is battery temp won't climb that high, but without a 30A shorepower connection you would have to run the generator for air conditioning. And who wants to run AC in a stored unit?

My intention is to store the pack at about 70% SOC. So my float voltage on the SCC is 13.2/3.3/cell. After 3.55/cell absorption the controller goes into float and the pack discharges to about 70% over a few days with parasitic loads - primarily the LPG sniffer.

Is it recommended to completely disconnect the battery from loads? Leave it at 50-70%?

I then have a settings parameter file I can load into the SCC for active use, with more normal/higher charging and float voltages.

Even when it was 100° F outside, my RV trailer (three season at best) was only 85° F inside. The trailer is not under cover. I'm OK with the batteries staying in place at those interior temperatures. @chrisski is in AZ and removes his batteries in the summer when not in use.

 

[Browneye]

Even when it was 100° F outside, my RV trailer (three season at best) was only 85° F inside. The trailer is not under cover. I'm OK with the batteries staying in place at those interior temperatures. @chrisski is in AZ and removes his batteries in the summer when not in use.

Thanks. Yeah, I've gone out there mid-summer and the thermostat says the temp is 98* in there. Even so, the battery wouldn't get that hot over one day. And we get good cooling overnight, 10miles from the beach. But gee, AZ has a lot higher temps than that, you could get heat-soaked days back to back that never get under 95*. BTDT got the wet t-shirt.

 

[robby]

I don't know about putting hard and fast numbers on all of this for every cell LifePo4 cell made. I had several long Talks with Fortress Power and from what i am told a lot of this stuff is still in Flux. Electrolytes and the way the cell chemistry is made is an ongoing process to get more power and more cycles. So much so that they said the latest cells they have been using are still being tested at slightly different charge parameters than the cells they used two years ago. This is 0.5 - 1V changes but he said they are seeing differences in deterioration and output power over cycle time already.

Going below 10% SOC was an absolute no no they told me, unless it was just a once and awhile thing like during a power outage. I think this is why they offer a conditional 10 year warranty on the EG4LL. I dumped the Logs on my battery and was surprised at how much data it kept. I have to look again but it seemed to be logging all parameters at very small intervals, certainly seemed like hundreds of samples per day. I was told that fortress also logs all the batteries data, but unfortunately I don't have the password to access it.

If you build your own batteries then I guess none of this matters but for people who are buying pre built packs, you may want to follow what they recommend or you may not get warranty coverage.

 

[curiouscarbon]

I don't know about putting hard and fast numbers on all of this for every cell LifePo4 cell made. I had several long Talks with Fortress Power and from what i am told a lot of this stuff is still in Flux. Electrolytes and the way the cell chemistry is made is an ongoing process to get more power and more cycles. So much so that they said the latest cells they have been using they are still testing them at slightly different charge parameters than the cells they used two years ago. This is .5-1V changes but he said they are seeing differences in derogation already.

Going below 10% SOC was an absolute no no unless it was just a once and awhile thing like during a power outage. I think this is why they offer a conditional 10 year warranty on the EG4LL. I dumped the Logs on my battery and was surprised at how much data it kept. I have to look again but it seemed to be logging all parameters at very small intervals, certainly seemed like hundreds of samples per day. I was told that fortress also logs all the batteries data, but unfortunately I don't have the password to access it.

If you build your own batteries then I guess none of this matters but for people who are buying pre built packs, you may want to follow what they recommend or you may not get warranty coverage.

thank you for pointing out that different batteries (Both LiFePO4) can have different electrolyte compositions, which drives different behavior ?

 

[Go2Guy]

tossing one more thing in the mix..

calendar aging and cycle aging both are temperature dependent

General LiFePO4 Degradation vs Temperature

Concerned about your LiFePO4 batteries ♨️Overheating♨️ or ❄️Freezing❄️and losing ability to hold charge due to operating temperature? This is a research paper that carries out charging and discharging at set temperatures, and evaluating the...

diysolarforum.com

just an additional reference, that studies the cycle aging vs temperature angle.

keeping the LiFePO4 cell cool should reduce *both* cycle aging and calendar aging

i spent quite some time reading that graph and doing my best quantify that into tangible statement, but not sure how exactly . . . would you mind summarizing in a way that. seems like great data, but very hard to summarize, i will add it as a link tho

I don't know about putting hard and fast numbers on all of this for every cell LifePo4 cell made. I had several long Talks with Fortress Power and from what i am told a lot of this stuff is still in Flux. Electrolytes and the way the cell chemistry is made is an ongoing process to get more power and more cycles. So much so that they said the latest cells they have been using are still being tested at slightly different charge parameters than the cells they used two years ago. This is 0.5 - 1V changes but he said they are seeing differences in deterioration and output power over cycle time already.

Going below 10% SOC was an absolute no no they told me, unless it was just a once and awhile thing like during a power outage. I think this is why they offer a conditional 10 year warranty on the EG4LL. I dumped the Logs on my battery and was surprised at how much data it kept. I have to look again but it seemed to be logging all parameters at very small intervals, certainly seemed like hundreds of samples per day. I was told that fortress also logs all the batteries data, but unfortunately I don't have the password to access it.

If you build your own batteries then I guess none of this matters but for people who are buying pre built packs, you may want to follow what they recommend or you may not get warranty coverage.

my goal for both me and others was to have a single source of the best settings and conditions for maximum longevity and minium cell stressl. I know its potentially not ideal for all cells . . but i had spent many many hours searching for such a summary and could not find a single compiled source, so after seraching for so along i decided gather all the data from others and compiled it. it may not be pefect, but its the very best data i could find for minium cell stress and maxium cell life. . also I wish for it to a "living document" so in other words as more data is found i will adjust accordingly. Just a question do you now of which cells may have alternate chemistries that you mentioned, how identify that there different and how you alter the charge recommendations for max service, for such cells . . i would be willing to add that data. . .
i was would suspect that being that planned obsolesce is a very real thing, manufactures, WANT you to use the cells in a way that will minimize there service life, many have said that these cells can last in theory for decades, however most major manufacter like battle born say go head and use the 100% SOC BUT who is to benefit from this, you or them . it doesnt seem there cellS are engineered in any significantly different way to allow continous 100% SOC use will out degradation in service life, AND IF THAT CASE WHY RECOMEND IT?? , which means IF you were baby the cells IN defiance of there recomendation you would likely double the service life. . BUT again would manufacture actually want to double the service life?? the only pockets that benefits is yours , not theres