Calculating the State of Charge of a Lithium Ion Battery System using a Battery Management System

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  • Опубліковано 28 лип 2024
  • The State of Charge (SOC) is like the fuel gauge in your car, telling you how much energy is left in your battery system. Calculating the State of Charge in a lithium-ion battery system requires an understanding of how the battery pack capacity and energy change. This understanding is critical before diving deeper into Coulomb counting.
    Topics Covered
    State of Charge
    State of Charge (Capacity) (SOCcapacity or SOCc)
    State of Charge (Energy) (SOCenergy or SOCe)
    Fuel Gauge
    Coulomb Counting
    Depth of Discharge
    Open Cell Voltage Lookup
    The state of charge is defined as the capacity remaining divided by the total capacity of the battery pack. We look at an example of how the state of charge is calculated. Using a discharge curve, he explains that this curve is not linear. Given this, the true state of charge is often different from the energy remaining. Looking at State of Charge (capacity) and the State of Charge (energy) we can understand the differences between these values and how to calculate the most relevant information.
    Coulomb counting is discussed next. Coulomb counting integrates amp hours and time to calculate the capacity removed from the pack. This provides a basis for SOC. The current sensor has drift and measurement error, so it is also important to have an open cell voltage lookup.
    Learn more at staflsystems.com.
  • Наука та технологія

КОМЕНТАРІ • 97

  • @johnnyflanker8509
    @johnnyflanker8509 3 роки тому +3

    Excellent explanation ! Glad I found your you. Will continue listening to all your videos prior to asking a question. Thanks !!

  • @apurvawatekar6720
    @apurvawatekar6720 2 роки тому +2

    Thank you for your videos. So simply explained. Your videos helped me to prepare for my interviews.

  • @vishnoor
    @vishnoor 3 роки тому +1

    Wonderfully done. Explained in very simple manner. So I guess one needs the charts for a battery pack to implement the socc soce and dod.

  • @stevecoscia
    @stevecoscia 2 роки тому

    Very informative video. Thank you for this. I just bought a 100Ah lithium battery and this explanation helps in understanding the app's SOC metric.

  • @ChuckJ1944
    @ChuckJ1944 3 роки тому +1

    GREAT ONE!!!! The calculas everyone needs!

  • @writerconnect1596
    @writerconnect1596 2 роки тому

    Excellent job. Clearly explained . Very eloquent !!!

  • @energyeve2152
    @energyeve2152 2 роки тому

    Clear and concise. Thanks for sharing!

  • @erfquake1
    @erfquake1 2 роки тому +3

    These videos are brilliant, Mr. Stafl, thank you, very easy to follow along. One gets into the noble field of lithium battery technology for environmental concerns, tries to brain-up on lithium battery characteristics and electrical fundamentals, and invariably gets stuck between principles and real-world application. Me for example. A coulomb meter out of the box needs initial settings ...specific to that battery config that it's monitoring... like capacity, full voltage "empty" voltage, and drift. A lithium battery pack's stated Ah may be, say, 40Ah, but is it the kind of parameter that ought to be tested for? And if it's "72v," obviously the range is going to be a few volts above (for full) and a bit above. (for depleted) But these are rules-of-thumb, and sort of nebulous to the amateur. To get specifics, should I test the voltage a.) immediately after charging, or after a day or two, and b.) idle or under load? In the interests of mitigating range anxiety, I'd like to make sure my settings are as specific/accurate as possible. You've got several videos. Is there one that may address these real-world scenarios best? Thank you.

  • @joechi7979
    @joechi7979 Рік тому

    Thanks for the introduction. I really learn something.

  • @mohamedzain8628
    @mohamedzain8628 3 роки тому +2

    Thanks a lot, good explanation, keep going.

  • @cangudem
    @cangudem 2 роки тому

    Thanks for the explanation. You save my life

  • @Pirelli.
    @Pirelli. 2 роки тому

    Very good explanation. Thank you!

  • @dhadumia
    @dhadumia Рік тому

    Thank you very much for such a great video!

  • @KeshavKumar20
    @KeshavKumar20 Рік тому

    Brilliant presentation!

  • @DennisMathias
    @DennisMathias 3 роки тому +2

    Great presentation! I knew there were nonlinearities in monitoring SOC and wondered how they did that. So now I know.

  • @peppi0304
    @peppi0304 2 роки тому +1

    Informative video of what i exactly didnt understand about how you know what nn% charged means of a battery. I would ve appreciated if you defined the first SOC you wrote right away as SOC_c and in two different graphs you once mention Ah-discharged and DOD. Could have made them the same aswell.

  • @heshanmahela7789
    @heshanmahela7789 3 роки тому

    Thank you very much very informative.

  • @sohailansariadvocate
    @sohailansariadvocate 2 роки тому

    great information provided thanks

  • @nileshparmar4246
    @nileshparmar4246 3 роки тому

    Nice explanation!

  • @bharathik.2911
    @bharathik.2911 7 місяців тому

    Very nice explanation!!

  • @snehal4582
    @snehal4582 3 роки тому

    Very helpful .
    Could you please explain calculation about charge or discharge Ah required for individual module depends upon min and maximum of cell voltage

  • @rajivmallipudi2679
    @rajivmallipudi2679 2 роки тому

    Hi Stafl...A very good explanation

  • @jimmytvglobal
    @jimmytvglobal 3 роки тому

    Great presentation

  • @Predato0000
    @Predato0000 2 роки тому

    Very clear and brilliant presentation. Thanks a lot!

  • @jimmytvglobal
    @jimmytvglobal 3 роки тому

    Very good explaination

  • @MuhammadQasim-92
    @MuhammadQasim-92 Місяць тому

    Excellently explained sir

  • @navnithrajsn1705
    @navnithrajsn1705 2 роки тому

    Excellent presentation bro

  • @electroumit
    @electroumit 3 роки тому

    Thank you. You are awesome.

  • @januaryonenineteenseventy4195
    @januaryonenineteenseventy4195 3 роки тому

    Love the video.

  • @oliverheeg3908
    @oliverheeg3908 2 роки тому +9

    In you example 50% SOCe corresponds to 58% SOCc, doesn't it?...I think you mixed it up as you plotted over Ah discharged and not over SOCc initially.

  • @faradayera
    @faradayera Рік тому

    Very nice Information sir 👍

  • @smde1
    @smde1 3 роки тому +1

    I would really like to see a LiFePO4 BMS among your product offerings .

  • @rizqizulqornain2539
    @rizqizulqornain2539 3 роки тому

    Well presented

  • @SeniorDonCarlo
    @SeniorDonCarlo 9 місяців тому

    I’m impressed 👏🏼

  • @Lalthlengliana.Khawlhring
    @Lalthlengliana.Khawlhring 3 роки тому

    Thank you 💐

  • @Thecrow999
    @Thecrow999 Рік тому

    Thank you!

  • @aed-smbenv7190
    @aed-smbenv7190 Рік тому

    Good larning sir

  • @Warpreacher
    @Warpreacher 2 роки тому

    Yes, you bloody legend

  • @JSGregg
    @JSGregg 2 роки тому +3

    Excellent video! Very helpful. One question, so does the BMS use voltage to determine the starting point for monitoring SOCe?

  • @sunpiljang2334
    @sunpiljang2334 2 роки тому

    I enjoyed the video.
    I want to learn more about BMS. Is there any institution or certification you can recommend?

  • @avatr7109
    @avatr7109 2 роки тому

    I couldn't find the Video about Calculating SoC for various things like SoC for Energy etc .

  • @tonymunn
    @tonymunn 3 роки тому +8

    At the 5:00 min. point, doesn't that point actually represent a greater than 50% SOCcapacity or is that 42% capacity used at that point? I think I understand. It seems that the 42% is more Depth of Discharge????

    • @staflsystems
      @staflsystems  3 роки тому +4

      You are correct. The 42% figure should be Depth of Discharge (DOD) or 58% SOC. This is an error on our part.

    • @0786RICARDO
      @0786RICARDO 2 роки тому

      @@staflsystems i was wondering the same. Thanks for the clarification

  • @serhatpolat4956
    @serhatpolat4956 2 роки тому

    Hello, what is the internal resistance of the 4S lipo battery or what is it? I have a 5200mah 50C battery and the internal resistors are showing 7 ohms.
    Do you think these values ​​are normal?

  • @FINwithFAME
    @FINwithFAME 6 місяців тому

    Your explanation beats what my professor has covered.

  • @edsonferraz1
    @edsonferraz1 3 місяці тому

    OK, excellent information. Do you have a SoC code using C++?

  • @avisengineering8952
    @avisengineering8952 Рік тому

    Mr. Stafl.. great videos
    Can you pl make more videos

  • @avinashpaulfernandes3932
    @avinashpaulfernandes3932 3 роки тому +2

    Hi! I have a small clarification.
    It was said that energy distribution is imbalanced. We know that energy is Voltage times Ah discharged. Even though the voltage is high in the first part the X axis is at a low value. Will it not be compensated?
    Thanks in advance for correcting me and clarifying it to me :)

    • @mohamedamr6228
      @mohamedamr6228 3 роки тому +1

      The x-axis is the Ah discharged from the beginning of discharge not the instantaneous Ah

  • @vikaspandey3537
    @vikaspandey3537 3 роки тому

    at 6:45, how can I calculate that area. can you please help me in this ?. I have a device from that, I have a graph of Amps and voltage over the time and now I want to calculate total wh. how can I do this ?

  • @juliushazzart9985
    @juliushazzart9985 Рік тому

    Thanks for the clarity and simplicity

  • @armanazote321
    @armanazote321 3 роки тому

    If the battery is design only to take 80 mWh but test result it can be overcharged up to 90 mWh is that a normal Reading? thanks you.

  • @srinivasponnaluri5800
    @srinivasponnaluri5800 Рік тому

    Isn't no load voltage for a given charge level is a function of temperature of the battery?

  • @laurabarnes3295
    @laurabarnes3295 10 місяців тому

    So please was the right voltage to charge a 11.1v System

  • @richpetrelli2783
    @richpetrelli2783 3 роки тому

    Excellent info. My question may seem elementary but I understand quite a bit of what was discussed from my EE background. That said, I find one thing confusing. Is SOC and DOD the same with two 100ah lifepo4’s in parallel as one 100AH standalone lifepo4? I realize that I am getting 200AH with the parallel config and only 100AH with the standalone battery. With 2 in parallel, I would think that it should take twice as long to reach the 50% SOC level with the parallel config than in the single battery config, of course assuming the same load on both configs.

    • @staflsystems
      @staflsystems  3 роки тому +1

      Hi Rich - thank you for your question. SOC and DOD are expressed in percentages, so they would be normalized to the size of the pack itself. For example, if you've discharged 25% capacity from a fully charged state, the SOC would be 75% and DOD would be 25%, regardless of if it is a 100Ah or 200 Ah pack. So if you have a constant load of say 25A, it would take you 1 hour to get to 75% SOC with a 100 Ah pack and 2 hours to get to 75% SOC on a 200 Ah pack.

  • @dannybalisi6744
    @dannybalisi6744 Рік тому

    very nice tutorial sir, in my set up sir im using 2 pcs 24v 100ah lifepo4 batt. in parallel connection. my question is why is it that in my volt meter, display of my scc and in my inverter was 100% and when i scroll down in my scc srne 60a mppt the soc was 54% what is the defirence betwen them? thank you sir i hope i'ved got an answer sir. thank

  • @vishva8kumara
    @vishva8kumara 2 роки тому

    If we have a function approximation for voltage / SOCc curve, it would be easier to normalize SOCe from voltage than a lookup table. I would like to model that. Wonder if there would be use to that.

    • @plkh9602
      @plkh9602 Рік тому +1

      modeling a Voltage/SOC and measuring SOC based on voltage curve could be easier, but don't forget to consider the voltage drops on the battery itself due to internal resistance and the variation in voltage when charging.

  • @surenbono6063
    @surenbono6063 2 роки тому

    Does 0% start from 2.5/3 voltage in phones batteries...?

  • @jihanas-syabani7889
    @jihanas-syabani7889 3 роки тому

    Awesome explanation! However, I just want to make sure if I get it right:
    1. DoD can be calculated through current measurement and time graph.?
    2. The battery capacity is calculated by comparing its measured voltage to its Voltage-DoD graph?

    • @yangjingxi179
      @yangjingxi179 3 роки тому +1

      The capacity is measured by coulomb counting. Capacity equal to integration of current by time.

    • @yangjingxi179
      @yangjingxi179 3 роки тому +1

      from current and time get SOC, from SOC get DOD

  • @junctek1802
    @junctek1802 2 роки тому

    Fortunately to see your popular science video, we made a battery monitor KG140F, which can check the remaining capacity and current voltage of the battery, and can export the discharge curve, I think you should be able to use it, we want to send Give you a test.

  • @wisalahmad1867
    @wisalahmad1867 3 роки тому

    My solar station software show SOC 3% and gradually increase but the voltage is above 12 so than why 3, or 5 or 7. It’s mean battery is too low . I am using Phoenix 230amp flooded

  • @sergeymarshall3173
    @sergeymarshall3173 Місяць тому +1

    Спасибо бро!

  • @ashujoshi1632
    @ashujoshi1632 Рік тому

    what is TCU error,While charging EV?

  • @johnnyzee383
    @johnnyzee383 3 роки тому +2

    " In general"..should be the name of this little video...

  • @a0cdhd
    @a0cdhd 2 роки тому

    Quite so Mr. Stafl

  • @nishpendumondal9338
    @nishpendumondal9338 3 роки тому

    Is it possible Calculate Cell Or Battery Pack Capacity if Amp's don't Known?
    PlZ Ans Me

  • @RogerRumbu
    @RogerRumbu 7 місяців тому

    Great

  • @swananddate6277
    @swananddate6277 3 роки тому

    if the battery is connected to load , How we gonna measure open circuit voltage in practical application ??

    • @NawtieBoy96
      @NawtieBoy96 3 роки тому

      you cant , you will need to use some other estimation methods

    • @DennisMathias
      @DennisMathias 3 роки тому

      My hypothesis would be that when the car is off or sleeping that that measurement is done. That's why when you park your car with 33% that when you get back in it might be 35%. Or 30%. It's possible it is more dynamic than that. It may do an instantaneous measurement during load reduction and calculate the delta from that.

  • @dahappychappy
    @dahappychappy 3 роки тому

    But Amp.hours is a measure of energy. You mean the peak power available, potential to do work goes down over time because the voltage drops? I am confused.

    • @SpeakerKevin
      @SpeakerKevin 3 роки тому

      @Nick Keller Yes, amps x volts = watts. The same 100 watt light bulb will draw more amps as the sos drops.

  • @dctech786
    @dctech786 4 місяці тому

    Interesting

  • @johnmeyer77
    @johnmeyer77 Рік тому

    So what voltage corresponds to 50% SOC? That seems like a very critical piece of information that you didn't provide because, if you are trying to estimate either the mAh or total energy remaining, the simplest thing is to measure the voltage and use that as a proxy. I watched this video hoping to learn these voltages, but was disappointed when you didn't provide them. And yes, I do realize that Coulomb Counting is the more accurate method, but that doesn't help you if you simply "come upon" a loose 18650 and want to know how much capacity it currently might offer.

  • @Nic7320
    @Nic7320 2 роки тому +1

    It would be better to define SOC(energy) as "SOE" or "State of Energy" and leave SOC for the lowly job of coulomb counting.

  • @Doctorbasss
    @Doctorbasss 6 місяців тому

    WATT-HOUR is the real term that define remaining range/energy. Capacity is voltage dependent and each Ah at the end of charge worth less than the first Ah. So the REAL SOC is Watt-hour defined and not Capacity (Ah)

  • @aspboss1973
    @aspboss1973 3 роки тому

    How do you the remained capacity"70ah"?

    • @yangjingxi179
      @yangjingxi179 3 роки тому +2

      For example, you have a battery with 100Ah capacity. And you discharge the battery with 30A for one hour, there will be 70Ah capacity left in the battery.

    • @aspboss1973
      @aspboss1973 3 роки тому +1

      @@yangjingxi179 thank you

  • @underdog5004
    @underdog5004 Рік тому

    "Remaing"

  • @r.e.tchoas5057
    @r.e.tchoas5057 Рік тому

    I got thrown off at the first 30 seconds no one got the misspelled word?

  • @rayvanokeizer2354
    @rayvanokeizer2354 3 роки тому

    Vak man!

  • @ioandragan3729
    @ioandragan3729 2 роки тому

    You look like PM.Justin Trudummy , or are you brothers??

  • @Cosme422
    @Cosme422 10 місяців тому

    From a professional video editor, there should never be any kind of music during any explanation videos ever

  • @ericseidel4940
    @ericseidel4940 2 роки тому

    I totally dislike your BMS system because it can handle the ODD number of 12 cells, are you aware that most of the batteries in storage applicatins are 16 cells LiFePo4 ?
    Then the total cost of just the BMS is way overpriced at 700+280+280=1260$ with the last monitor only half populated. Totaly ou of the residential storage market!

  • @batteriesforeverything7112
    @batteriesforeverything7112 2 роки тому

    Not impressed

  • @jeebusk
    @jeebusk 2 роки тому +2

    I think this presenter is mostly presenting his own confusion, there's no actual distinction between capacity and energy.

    • @4G12
      @4G12 Рік тому

      That's only true if internal resistance and voltage discharge curves are non existent.

    • @sonicspring6448
      @sonicspring6448 Рік тому

      Capacity is charge (Amp hours) and Energy is Joules (Watt hours), so the voltage profile is important.

  • @thedolphin5428
    @thedolphin5428 Рік тому

    Simplistic, theoretical nonsense, not corresponding to the reality of any particular LiFePo4. Have you ever bench tested dozens of batteries? Not one of them ever follows the maths or the graphs. New vs old; quality internal chemistry vs recycled lithium; hourly/daily/seasonal temperature variations; balance between cells; number of cycles; all conspire to make the only real SOC a specific measure of currents in and out from a daily top balanced cell reference point compared to the maximum actual battery SOH (State of Health). I have never, within real life situations, found a SOC figure to be any better than about +/- 8%.
    The only true SOC is