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yes that's the way to do it, I mean even you fail still a result is a result considered good or bad, atleast you can make some outcomes out of it, let me know about your process, that would be interesting :cool:?

thanks for the suggestion however at the moment I don't want to include the temp factor yet as it will get more complicated(I know temp can be ignored), atm I am doing my test at room temp (25C). in the industry what I know is that temp sensors are mounted in the middle of every 4th cell for a...

sure ! AI would make sense after the collection of the right data for all the possible scenarios. that's the future for sure

did you even open the pdf I attached at the bottom ?

he said for charging we do calculate using the formula which is nothing diff but for discharging we don't bother using formula but instead, we assume it to be 100% and as for the formula part, if you are really curious then here is research paper that I am following. you can have a look at it :)

oh sorry , it should be 0.1% and yes I have gone through that site already long ago

watch this at 14:13 ;)

Can I know how did you achieve this graph of Rested OCV vs SOC . thanks

usually I have read that for Lfp self-discharge over a month is 3-5% so in this case how can one account for this in our meter readings? Soc reading - (3%/30days = 0.003% per day ) is it correct ?

just to clear I am after SOC calculation and want to know what effect the CE and Peukert has got into it. the more effects are taken into consideration the more accurate I can be in estimation

so can I then say that for a LFP battery temp change on Columbic Eff is non-existent or can be neglected?

this was very useful for me to have an overview of how its done practically , also one question what does this temp compensation 0 mean here?

thank you for the correction so if I decide to lets sat do 5 cycles complete chg / dchg on 0.1C then 0.2C ... all the way to 1C with increments of 0.1 here .. later have them averaged and put them in a table so I know if the battery is in this rate I choose that respective value of CE. would...

thanks alot for this , yes I have gone to that article before and for Li chem the Peukert effect is quite non-existent

just for your own info, I have found the formula for both stages in a research paper and they are quite a diff from each other :)

Dear all, I have some small LFP cells that I want to calculate capacities of , they are rated 3400mah from the manufacturer and I have attached the datasheet for it. I would also keep things simple here so I am maintaining the temp of my exp to 25degrees. My question here is how many no of...

Thank you both @Ampster and @toms for your valuable replies to this thread . I really appreciate it. In reply to @Ampster statement, I would like to highlight again that I asked for CE formula both for discharging and charging stages. I created this thread after coming from google's general...

with due respect if you read this particular thread you will understand what I am really after, CE is a completely different topic and it has got its own complexities. saying temp , C-rates , shunt is very easy but telling the right procedure and steps arent. if it was that simple , I would have...

hmm so If I talk about data here which is my most interesting point of interest, what If I log the capacity values as well for these voltage points so when I do the estimation using CC. I will go to my lookup table and based on what my current battery cell voltage is I will use that Cap(SOC)...

what do you mean here by different sets of data ? do you mean I repeat the test at different C-rates for eg one time at 0.1C , next time 0.5C and so on or do you mean repeat the same test but multiple times at a fixed rate? also will this be my charging Coloumbic eff or dicharging Coloumbic eff ?

your proposal sir ? ;)

yes sure , thats why I have stated above that I am doing it based on a shunt , I am discharging based on capacity and whatever OCV I get I save that on the table. I just want to know whether I should I charge my cell to 3.65V and then start test or give it rest for 24hours or several hours...

this is part of my degree project, I am a student :). if I could have bought (afford) the Victron shunt then I shouldn't make this thread haha but here as I am studying batteries and want to understand the LFP chem in-depth as later I will jump to bigger cells and so on ?.

yes exactly this chart and I dcg and chg at 0.2C (0.68A) compared to rated 3.4A(1C) , I want to create this chart and record this OCV vs SOC and also respective capacity in a table

yes completely agree with your point , Can you please suggest me how should I plot my table for SOC vs OCV using the shunt .... I can then follow that , also I went with 0.2C so Vter = Vocv+IR so at 0.2C the current is fairly less and then after giving hours of rest and measuring OCV I can then...

I think I need to restate my point. what I mean instead of creating OCV vs SOC or DoD ( just assume soc would be dod in dchg mode) , instead of relying only on open circuit voltage vs SOC/DOD it would be more sensible to plot OCV based on Capacity charged / discharged. usually a discharge is...

alright after getting a shunt-type meter what next? how should I create ocv vs soc plot ? if I do based on capacity approach which is also what I am after then ocv vs soc will be meaningless right? a better way would be to create a Capacity discharged vs SOC table?

really appreciate your extensive reply and after reading all this I don't think I can pull this off taking the time into consideration here so back to my question that I asked above can I find CE for diff C-rates and then fit them into a lookup table so based on my current value (C-rate) both of...

just to clarify I am working on 3.4Ah a small (blue) cylindrical LFP cell and as I saw those percentage numbers sepcially for 1C chg / dchg rate I am wondering if that 90% can happen for my small cell too I really doubt about it. do you have these percentages based on your own tests or from...

thank you for detailed explanation, and I really liked the two attachments, specially the last one you posted with OCV vs SOC. now can you suggest to me how should I go with my OCV vs SOC test so as to get an accurate and sensible graph like yours? If you read my steps already you can rectify...

I am here to get into trouble so wanna do the stuff myself for a better understanding :cool::)

Hi team members I am interested in knowing how to create my own SOC vs OCV chart for an LFP cell type, here's what I have done previously 1- Performed capacity test and make this cap a fixed value to be discharged/charged in small increments wrt to percentages of SOC 2- in my case I choose...

Hi all I want to calculate CE (Coloumbic eff) of a battery for discharging and for charging but I am struggling to find the right formula for both cases. I do know the basic one i.e. Qdchg / Qchg * 100 . here I also want to know whether I should keep my chg and dchg rate fixed . is it...

Hi all I want to calculate CE (Coloumbic eff) of a battery for discharging and for charging but I am struggling to find the right formula for both cases. I do know the basic one i.e. Qdchg / Qchg * 100 . here I also want to know whether I should keep my chg and dchg rate fixed . is it...