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Discussion Starter #1 (Edited)
Hey everyone,

I've created a simple charging time calculator, should give reasonable results. Most likely helpful for curious potential buyers or fresh faced EV owners. My first contribution to the community since getting my i3 three months ago :)

https://leccy.net - Electric Car Charge Time Calculator

Feedback always welcome.

(I mentioned this on another thread when I was looking for data to compare results to, wanted to give it its own post now I've done more work and for anyone who might have missed it)
 

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I don't think the function vs time is a curve. It is more like a ramp-up curve followed by a straight line followed by a ramp- down curve. My gut feel is you are over-estimating very slightly as a result. The Ampera, which is what I am used to is a bit different as zero is above zero and full is below full so most of the time it charges in the straight line part of the graph then there's about 15 minutes at the end while it sorts out the 12v and does other stuff after reaching nominally 100%. Current drops right down for this last 15 mins.


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Hmmm, thanks for that. Does the Ampera charge with rapid DC? Generally, as the power, the lower the curve that is applied. It's been really hard to get close but there have been reasonable results with i3 / Leaf.

I've considered, and it would be possible for me to store a charging profile / curve for each charger type and/or each car. I may still do this, but it will require gathering even more data.
 

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No. 3.3 Kw only from type 2 to type 1 or type 1 only. Plus the 10A or 6A with granny box.
If you are wondering how long it will take to charge with an Ampera then you are missing the point of the design.


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It's a really good idea and worth refining in my view. Tesla publish lots of charge profile data which if you could map 3 functions to it, I think it would scale to most if not all BEV models with DC rapid.
Worth adding the Mercedes B class in so it is helpful for prospective customers given that it has no DC charging.


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Hey everyone,

I've created a simple charging time calculator, should give reasonable results. Most likely helpful for curious potential buyers or fresh faced EV owners. My first contribution to the community since getting my i3 three months ago :)

http://leccy.net - Electric Car Charge Time Calculator

Feedback always welcome.

(I mentioned this on another thread when I was looking for data to compare results to, wanted to give it its own post now I've done more work and for anyone who might have missed it)
Great site although can't get it to allow me to charge at 6.6 even though I selected 6.6 Tekna LEAF.
 

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If you wanted to make it accurate for Volt/Ampera you could use the theoretical time and add 20 minutes. That would pretty much always come out matching real world. It is because the usable part of the battery capacity means it charges nearly all the time at the 14A rate ( into the battery) on a 16A available supply, except for that last 15 mins. It never gets near enough to full or empty to require a slower rate.


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Discussion Starter #8
Great site although can't get it to allow me to charge at 6.6 even though I selected 6.6 Tekna LEAF.
Hmmm, I can't report this. For me, select Leaf then Tekna, check the checkbox for "with 6.6kW on-board charger", then choose a high power AC outlet like Type 1 or Type 2... Results page should state 6.6kW as the charging speed.

If that exact path doesn't work, let me know your browser and OS please :)
 

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Hmmm, I can't report this. For me, select Leaf then Tekna, check the checkbox for "with 6.6kW on-board charger", then choose a high power AC outlet like Type 1 or Type 2... Results page should state 6.6kW as the charging speed.

If that exact path doesn't work, let me know your browser and OS please :)
There we go. Didn't see the extra tick box for the 6.6. ‍♂

All good now.
 

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Good thinking, @tomk. This is something I've wrestled with a fair bit as well, though only for the i3 60Ah.

My initial workings led me to use a logarithmic profile, much as you have. However, David Bricknell's book (ELectric Vehicles and the BMW i3), section 5, gives a completely different profile. Given that, it seemed sensible to put the project on hold until I could get some empirical data for a real world comparison, and that won't happen until I need to get some use of rapids and the weather's suitable for standing around watching the charger and making notes for half an hour.

On your website, my outdated laptop can only load the initial page; from that, there's no response to clicking on any of the vehicles. Clicking "other" and accepting all the defaults (the computer couldn't change them) eventually gets stuck on a "loading" screen. So, I think it's missing some essential software to run this. I was quite surprised when the even older desktop ran it fine! In terms of the i3 60Ah REx, my main concern was that the capacity listed is afaik the nominal capacity, but only 18.8kWh is available: therefore, the charge required for a given % increase is a lot fewer kWh than your model suggests. Minor tweak needed there, maybe.
 

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Discussion Starter #12
On your website, my outdated laptop can only load the initial page; from that, there's no response to clicking on any of the vehicles. Clicking "other" and accepting all the defaults (the computer couldn't change them) eventually gets stuck on a "loading" screen. So, I think it's missing some essential software to run this. I was quite surprised when the even older desktop ran it fine! In terms of the i3 60Ah REx, my main concern was that the capacity listed is afaik the nominal capacity, but only 18.8kWh is available: therefore, the charge required for a given % increase is a lot fewer kWh than your model suggests. Minor tweak needed there, maybe.
Oops, sorry - I've not tested the site on legacy browsers - I would suggest trying the latest Google Chrome browser if you're able to install it (though perhaps the latest version isn't available to you).
I started with the available kWh amount but later changed it to the full kWh amount because, and there was a reason but I can't remember it now! Does the i3 report 100% as being 18.8kWh or 22kWh? I should revisit this.

Hey @tomk please add Hyundai Ionic Electric as well, please :)
Will do, in the new year!
 

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Great site - good bit of work - love it - thank you.
 

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Hi @tomk

I didn't get to watch much of the daytime charge I did on Tuesday (my i3 60Ah REx, using an EH "50kW" CCS point), but when I was there and not distracted I made some notes off the charger's display.

SOC of "69.5%" actually means when the display changed from 69 to 70.
SOC : Amps : Volts
69.5% : 78 : 396
70.5% : 74 : 396
71.5% : 70 : 396
72.5% : 65 : 396
80.5% : 41 : 396
85.5% : 28 : 396
86.5% : 25.5 : 396
(the final 25.5A was flipping between 25 and 26 and back again)

Does this sort of data help you? These readings suggest to me that, in this SOC range and within the accuracy of the readings, the decline in the current has a near enough linear relationship to SOC. That's pretty much what David Bricknell's book (see #11) sets out.
 

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@tomk I think there is an error on the 22kW Type 2 calc for a Tesla Model X.

The High Powered Charger on all model Xs only takes 16.5kW max (3 phase at 24A) and not 22kW. It is the same for facelift Model S. Only original Model S with Dual Chargers can pull a true 22kW.
 

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Great work @tomk!

Would be great if we could work together on building this into EVHWS as an API? It then could then be integrated into the route planner to provide a more accurate journey time taking into account charging.

Sounds like fun to me!
 

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Discussion Starter #18
Hey @tomk please add Hyundai Ionic Electric as well, please :)
Done! (Pure electric only)

@tomk I think there is an error on the 22kW Type 2 calc for a Tesla Model X.
The High Powered Charger on all model Xs only takes 16.5kW max (3 phase at 24A) and not 22kW. It is the same for facelift Model S. Only original Model S with Dual Chargers can pull a true 22kW.
I hadn't realised this! I've changed the upgrade option to 16.5kW, I'll add the 22kW upgrade option to early Model S models once I can fathom just exactly which ones they are... (I had found a huge matrix table online somewhere that may have the information but I can't for the life of me remember where it is)

Great work @tomk!

Would be great if we could work together on building this into EVHWS as an API? It then could then be integrated into the route planner to provide a more accurate journey time taking into account charging.
Yeah sure, I can do this. It will be a bit slap-dash, but it's now on my list.
 

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@tomk - I just recommended your site to the Tesla Owners Group on FB.

However the chap asked: "Hi would someone more equiped than me work out how long it would take to charge my 90D facelift with the upgraded charger, from say 5% to 90% using an 'up to 22kw' destination charger.
thanks in advance i cant get my head around it."

Using your site to answer the above, I have 3 comments:

1. The high power charger option is listed as 16kW, not the actual 16.5kW. However when you give the options later you do correctly cap it to 16.5kW
2. The answer given for the above scenario if you select 5%-80% instead is 4 hours and 60 mins!!! ;-) That was 5 hours when I went to school...
3. The units in the explanation are wrong, you use kW when you should be using kWh to explain battery capacity and amount of charge.

Still absolutely loving the site, and will be handing out the links when I give a talk this week in the office on EVs to interested colleagues.
 
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