By now everyone's seen this chart:
It's crap. Why? Because the Dynamic Stress Test (DST) Cycle they are using on the x-axis is the actual test cycle that only goes X% based on the legend (i.e. 10% for 75-65%, 60% for 100-40%) and *not* a battery "cycle" that would make comparing these lines more equivalent.
In reality each line should be scaled horizontally to match.
Being annoyed by this chart for the umpteenth time, I decided to (try to) do something about it.
First I recreated my own version of the crap chart by populating some of the underlying data points so that I could use those to extract more meaningful info.
My version of the same old crap:
Looks pretty good, right? I mean, it looks like crap, but it looks the same(ish) as the source chart ... or close enough.
So, based on that I labelled the datapoints by the number of rated miles consumed based on 100% = 310 miles...
The whopping gigantic datapoint circles are roughly equivalent 'mileage' based on using the largest number available from the most-DST-cycled info (260,000 miles). Some of the others are at 260k as well, others at 279k. Roughly.
Here's the same slightly less crappy chart, with less clutter (removed the labels):
My takeaway is ... there's still something to be learned from the chart. There's not massive amounts of difference, but black, blue, red are all below 90% at the 260-279k miles mark. What do they have in common? They all charged to 100%. Red did the best cycling 100-40. Black worse 100-25, Blue worst 100-50. Why? I dunno. My takeaway ... 100% = bad.
Green is a bit better above 90%, maybe 91%. That charged to 85% and down to 25%. Takeaway, 85% is better than 100%.
Light blue is again a bit better maybe 92%. That one charged to 75% and down to 25%. Takeaway, 75% is better than 85%.
Orange, way the F off to the right, looking all awesome in the original chart ... is not so awesome. That one is in the middle of green and light blue and it charged to 75% and only down to 65%.
Purple (mauve?) is actually the winner. It also charged to 75% but only ran down to 45%. Takeaway? I dunno 75% is better, and super shallow isn't best, but averaging closer to 50% is better? Or that datapoint is crap (it is higher than the purple trend).
Overall takeaway ... 75% better than 85% better than 100%. Difference after a ton of miles might be 93% of original capacity vs 89% of original capacity.
DISCLAIMER: (i.e. don't come at me bro) ... this is *NOT* based on *Tesla's* cells or their super-de-duper awesome improved magical chemistry that might be waaaay amazeballs better than this. We don't know. But anyways, given this data that came from somewhere that might be half-decent but was visualized in a crap way and keeps getting thrown around incorrectly all over forumss and youtubes and the twitters... it might learn us sumthin' gud? I dunno. Take it as is.
If you found this useful, click like, don't forget to subscribe, and blah blah blah.
All content except the original crap chart, Copyright (C) 2019 Darth fricking Vad3r.
(If I see this in someone's youtube video, so help me ... I will not hestiate to force choke you through the interwebs!)
That is all.
Original crap chart from: https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries but who knows where they got it from? Do you know? If you do, let us know.
It's crap. Why? Because the Dynamic Stress Test (DST) Cycle they are using on the x-axis is the actual test cycle that only goes X% based on the legend (i.e. 10% for 75-65%, 60% for 100-40%) and *not* a battery "cycle" that would make comparing these lines more equivalent.
In reality each line should be scaled horizontally to match.
Being annoyed by this chart for the umpteenth time, I decided to (try to) do something about it.
First I recreated my own version of the crap chart by populating some of the underlying data points so that I could use those to extract more meaningful info.
My version of the same old crap:
Looks pretty good, right? I mean, it looks like crap, but it looks the same(ish) as the source chart ... or close enough.
So, based on that I labelled the datapoints by the number of rated miles consumed based on 100% = 310 miles...
The whopping gigantic datapoint circles are roughly equivalent 'mileage' based on using the largest number available from the most-DST-cycled info (260,000 miles). Some of the others are at 260k as well, others at 279k. Roughly.
Here's the same slightly less crappy chart, with less clutter (removed the labels):
My takeaway is ... there's still something to be learned from the chart. There's not massive amounts of difference, but black, blue, red are all below 90% at the 260-279k miles mark. What do they have in common? They all charged to 100%. Red did the best cycling 100-40. Black worse 100-25, Blue worst 100-50. Why? I dunno. My takeaway ... 100% = bad.
Green is a bit better above 90%, maybe 91%. That charged to 85% and down to 25%. Takeaway, 85% is better than 100%.
Light blue is again a bit better maybe 92%. That one charged to 75% and down to 25%. Takeaway, 75% is better than 85%.
Orange, way the F off to the right, looking all awesome in the original chart ... is not so awesome. That one is in the middle of green and light blue and it charged to 75% and only down to 65%.
Purple (mauve?) is actually the winner. It also charged to 75% but only ran down to 45%. Takeaway? I dunno 75% is better, and super shallow isn't best, but averaging closer to 50% is better? Or that datapoint is crap (it is higher than the purple trend).
Overall takeaway ... 75% better than 85% better than 100%. Difference after a ton of miles might be 93% of original capacity vs 89% of original capacity.
DISCLAIMER: (i.e. don't come at me bro) ... this is *NOT* based on *Tesla's* cells or their super-de-duper awesome improved magical chemistry that might be waaaay amazeballs better than this. We don't know. But anyways, given this data that came from somewhere that might be half-decent but was visualized in a crap way and keeps getting thrown around incorrectly all over forumss and youtubes and the twitters... it might learn us sumthin' gud? I dunno. Take it as is.
If you found this useful, click like, don't forget to subscribe, and blah blah blah.
All content except the original crap chart, Copyright (C) 2019 Darth fricking Vad3r.
(If I see this in someone's youtube video, so help me ... I will not hestiate to force choke you through the interwebs!)
That is all.
Original crap chart from: https://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries but who knows where they got it from? Do you know? If you do, let us know.