วีดีโอ

Moi, je parle français comme ci comme ça. Je n'ai pas la capacité de créer des conférences en français. Pardon. Peut-être que les sous-titres TH-cam peuvent vous aider ?

You would have the same response for just about all the technology. TDR is pretty much a standard method of hitting a cable with a pulse, and waiting for the echo signal to measure the distance and amplitude of the signal. I recommend that you get a unit with TDR and Arc Reflect. Arc Reflect is the "high voltage" TDR signal that gives you more flexibility in addition to the TDR. In oil filled cables, which may be similar to your mineral oil cables, the rule of thumb is that it needs a 40 KV thumper. Let me know your thoughts. Good luck.

It is an industry standard test. PI is a 10 minute test.

Hi sir... which standard it is mentioned?

@@nahashamsa2791 IEEE Standard 43-2000

@@OmniBaddie Please read part 12.2.2. PI is not recommended if the 1 min IR value exceeds 5 Gohms.

In the PI art, the molecules are referring to insulator molecules - usually plastics. I would agree with you for conductors. Then again, if we are getting these minuscule current flows from plastics, I suppose we are stripping the outer electrons from the outer orbitals of the molecules with the high voltages.

Call or email. (832)519-8117. joe.istre.megger@gmail.com

Email me and I can get you a quote: joe.istre.megger@gmail.com

However you do the calculation, the result should be unit-less. It is like a bucket of water: it has a capacity in gallons or liters, and it has a present amount of water inside it also in gallons or liters. For battery engineers, I recommend using watt-hours to do the calculations, although you may be asked to use the amateurish "amp-hour" specification. I consider "amp-hours" an amateur calculation based upon obsolete lead acid rules of thumb, yet we have to use them since much of the market demands such specifications. You can use coulombs, if you know what you are doing, but that may just complicate things. If you are indeed a battery or systems engineer, all this is quite basic, and one must simply keep track of the units carefully in a spreadsheet when specifying or simulating the system.

That is a million dollar question. There are some researchers working on this. I am one of them! I do consultations, if you need.

The tested system acts like a capacitor. The theory of a capacitor in a DC system is that during its initial stages, there are some current transfer between the two conductors. After some time, it tapers off and no current transfer occurs as it is an open circuit. So for a PI test, the first minute is like the initial stages where there are some small current transfer, hence the lower resistance due to ohms law. Around the 10 minute mark should be the point where there's no current transfer, hence the higher resistance due to ohms law.

You must perform a capacity test, at a miminum. Take this number in either amp-hours or watt-hours and divide by the rated capacity of the system in the same units. Typically, this is what most people call the State of Health, although different companies and groups may calculate it differently. Some people may emphasize the measured internal impedance against the expected internal impedance, as another indicator of State of Health.

@@joeistre2717 but what strategy is best fit for a online BMS in a vehicle.?

@@duke5872 This is the million dollar question. The answer can be very expensive in research time and data collection. You will have to do something like a Kalman filter. You know, Baysean statistical methods, that use historical inputs and present inputs to estimate present measurement - state of charge in this case. And, of course, the algorithms must have biased configuration parameters under various conditions, because, for example, a settled voltage level is a stronger input signal than a voltage measurement taken under a high current condition.

Thanks for the recommendation, Syed. What is the application for your systems? Grid, vehicle, portable, etc?

@@joeistre2717 Thanks for your reply i am working on Battery Management System

Very good question. This question is the Piece de Resistance of battery systems engineering. So … you can integrate the current over time. The problem is that current sensors tend to be inaccurate, and integration accumulates the errors over time. You will need a plot of State of Charge versus Open Circuit Voltage. Then, you will need a plot of the resistance of the cell as a function of State of Charge. So, you will have to calculate SOC from integration of current over time, then go find the resistance at that particular SOC, and calculate voltage drop, and then Back-Estimate Open Circuit Voltage to get State of Charge. Thus, for calculations, you will have measurements of only current and Vcell (measured live at the cell terminals). (1) use integration to find estimated SOC. (2) Use Measured cell voltage and resistance tables to back-calculate Open Circuit Voltage. Determine the error between the two. This is not typically easy to do. It often takes a lot of data to do these calculations, and with very basic data, the calculations can be off 25% or more, depending on the precision of the measurement and the precision of the estimation algorithm. If the numbers are not accurate enough, you will need to develop a circuit model, and if you are doing precision research, you may have to develop a Kalman Filter class of models for your cell. But if you are experimenting for personal use, or simple and basic consumer electronics, this may be sufficient.

joe.istre.systems@gmail.com

Yes. I have written several battery simulators over the past 10 years. Can you send me your contact information? MY email address is: joe.istre.systems@gmail.com Thanks!

Can you send me your contact information? MY email address is: joe.istre.systems@gmail.com Thanks!