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Assuming active cooling (non-Nissan Leaf), our battery packs will retain more capacity if charged more quickly. In fact, capacity loss is directly proportional to charge time. If it takes 4 times as long to charge, you will lose capacity at 4 times the rate.

Dry, but extremely informative video:

https://www.youtube.com/watch?v=9qi03QawZEk
 

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Dry, you say? How about arid?
So, after 30 minutes of sitting through this, I think I'll just avoid charging my battery when its temperature is over 100 degrees. Oh, wait, the car does that for me!
 

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I found the presentation fascinating...

The data presented does not support the assertion that slow charging is worse for the battery than fast charging, by the way; if anything it's showing an association between time and degradation and since no data was presented on idle time no conclusion at all about whether time spent idle causes more, less, or the same amount of damage can be drawn.

(By the way, the killer is time and temperature at high voltage, which is the same as high SoC. Don't put the cell at a high voltage, it'll last longer - this is done by limiting the SoC window. Don't put the cell at high temperature, it'll last longer - active cooling. The Volt uses a more temperature sensitive chemistry but mitigates it in other ways - it is unlikely that temperature related degradation will be an issue at any charge rate.)
 

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I heard from this presentation is the degradation is due to time at high temperature and fast charge discharge cycles mask the issue. That's not the same as "slow charging degrades the battery." Fast charge/discharge cycles simply beat the degradation of the time at temperature curve getting more cycles counted before degradation.

Sounds like GM engineering took this into account and incorporated active thermal management.
 

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This thread reminds me of a question I had when I leased my Volt back in 2013. I wonder when I will start to see decreased AER? Given the conservative use of the pack capacity (10.3 of 16.5) and the active pack thermal management, I think the answer is, not for quite a while. I am still seeing 44 miles on the GoM every morning during the 8 warmer months. And I usually get pretty close to that, around 42 or 43 on days I actually use the pack up, which isn't often.
I can only guess that most G2 Volt owners are seeing around 60 most months of the year.
I charge 98% of the time in a cool garage at 110. I have a feeling my pack is going to last a LONG TIME. Which is a big part of why I bought my car at the end of the lease.
 
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