Calculate EV Charge Cost

Discussion in 'General' started by Esprit1st, Mar 18, 2020.

  1. I programmed a little website to calculate an EVs charging cost.
    You can enter some basic information into the calculator like battery size, State of Charge and costs (per minute, session, kWh) and it will calculate the time needed to charge, the total and the per kWh cost.

    With all these different charging providers all calculating the cost differently it's sometime hard to compare costs.

    The address is:
    https://www.ev-charge-cost.com

    Please let me know here what you are thinking, if it is helpful or not and if you have suggestions for improvement.
     
  2. interestedinEV

    interestedinEV Well-Known Member

    Nice. Again, if you can develop a mobile version, that would be awesome. I am not sure how you programmed it, but you do not have to make a app but merely a version that can resolve on mobile phones. When you need this program is when you are on the go, not say at home.
     
  3. ericy

    ericy Well-Known Member

    The first thing that jumps out at me is that charging rate isn't the whole time. The charge rate at any given time depends on SOC and battery temperature, and typically tapers off as the SOC gets higher and higher. A tool like ABRP takes some of this into account, but even there I don't see any indication that they have awareness of how temperature plays into it. Some of that is proprietary, of course.

    https://forum.abetterrouteplanner.c...ng-data-for-the-bolt-kona-niro-soul-and-leaf/
     
  4. Yes, I was planning on doing a mobile resolution. Definitely.
    Also a good point. I was thinking of implementing a taper curve for different cars. That will be some work. Right now at least you're getting an estimate to be able to compare between different providers.

    Thank you both for your input!
     
    electriceddy likes this.
  5. I added quite some features. The calculator is now able to use a charge-profile for a car. Right now the only car actually using a charge-profile is my beloved Kona, since it is my car.
    If anybody can supply a charge-profile for any other car, no matter which format, I'll be happy to implement.
    However, it calculates a flat "curve" for other cars as it will show in the graph that it will calculate! ;)

    Please let me know what you think. Any input is welcome!
     
    Last edited: Apr 2, 2020
  6. Works pretty good! On some chargers that are higher than 50kW, what number should be entered? The most I have seen charging on mine is about 69 kW on a higher kW fast charger. Should it be the max of the charger, or the max I have seen on my car before? Your instructions say max of the charger or car, but is that correct?
     
  7. You get the same costs if select 80 kw max charge rate compared to say 150 kwh (at least with Kona 64)
     
  8. Just tried that, and you're right, indeed.

    Maybe this is asking for too much. But can outside air temp be added as a parameter and used to calculate speed and costs?
     
  9. That would also have to accommodate losses from TMS operation be it cooling or heating the pack due to the ambient. A bit of a challenge.
     
  10. That is the maximum a charger could deliver. If a car has a charge-curve saved (like the Kona) the program knows to respect the max charge the car can take. Just like in a real scenario, you will not get a faster charge on a 350kW charger than on a 150kW charger using the Kona. However, for (currently) all other cars that is ignored, since I have no charge-curve available for those cars, so it will take and calculate whatever you put as max charge rate into that field.

    If you put in a lower charger max rate than the car can take it will assume that as a maximum, but when the max charge rate of the car drops below that (top end tapering) it will follow the cars max charge rate. You will see that neatly in the graph if you put the charge rate max as 50 and endSOC to 100. The graph then shows you how it tapers down.

    I hope this answers your question.

    Currently the program calculates a 90% charging efficiency in general. Adding a temperature slowdown feature is really difficult, since there is so many variables. The OAT (outside air temp) wouldn't matter, if your battery is heated up good because you just pulled into a charger after a 2 hour drive. How would I be able to know and calculate that?
     
    Last edited: Apr 3, 2020
    R P likes this.
  11. I added the option to save your calculation to a "scratch paper" so you can better compare calculations and charge points.
    Let me know what you think about it: https://www.ev-charge-cost.com/
    Thank you!!
     
    electriceddy likes this.
  12. Seems to work .Thanks :)
     
    Esprit1st likes this.

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