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Discussion Starter #1
This is the third and final planned video on how tapering works in optimal conditions for a Bolt at a 150 amp (or more) station. 55kW is the max at which current model years can charge, so even if you're at an Electrify America station sporting a 350kW label, you'll be topping out at what is presented in this video.
These were created mostly for beginners who lack an understanding of the taper curve. I hope you find them useful nonetheless.
As before, extra special thanks to @Zoomit for some of the the graph data, and @Vertiformed for the timing data and feedback. Their posts are and remain more informative than I can ever hope to be on these forums.
 

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Is the "curve" altered by very cold and very hot temperatures, or does the full charge (60kWh) simply not take you as far? Are the dropoffs at the same SoCs and simply take longer to get to the next taper point, or do the tapers occur at much less SoCs? Is it tough getting the energy in or just getting it out again?
 

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The data more less echoes my observations a few months ago. Good video!
https://www.chevybolt.org/forum/82-charging-batteries/32809-best-charging-curve-i-ve-seen-yet-100kw-dcfc.html


Is the "curve" altered by very cold and very hot temperatures, or does the full charge (60kWh) simply not take you as far? Are the dropoffs at the same SoCs and simply take longer to get to the next taper point, or do the tapers occur at much less SoCs? Is it tough getting the energy in or just getting it out again?
I emphasized the right ones in the quote.

Essentially, the maximum current gets limited. So while the taper points for a given current remains the same, the current pulled from the charger is lower, so you may not actually see the tapering until much further down the line.

For an example, there's a taper point at 50% that limits the current draw from 150A to around 110A. If I charge my Bolt at a charger that's only capable of 110A output, I won't see tapering at 50% since I would only be getting 110A maximum at or before 50%. The curve will remain stable until around 67%, when the current limit goes from 110A to 65A and tapering occurs. When I charge my Bolt on a really hot day, it seems to limit the charging current to around 100A maximum and a similar thing happens.
 

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Discussion Starter #5
@wesley your graphs are great! I'm just seeing them now and pouring over them. Lots of great data presented clearly.
 

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This is proof that LG and GM worked together to protect the cells and extend their lifetime. No one who drives any EV wants to overheat or overcharge its battery, so tapering works to prevent any degradation. I have see over charged cells when the internal temperature climbs enough to heat the limited moisture inside and create vapors that expand the package. EV must never reach that point, or else the battery structure will be affected.

So the lower current tapering is normal and expected for a well engineered EV, such as the Chevy Bolt EV.
 
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