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Will "short charges" (i.e. 15-20-30 minutes) have a negative affect on battery life?

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During the summer months, I was charging to 70% and returning at the end of each day at about 35 to 40%. I felt playing in this range was probably the easiest on the battery. With the onset of cold weather, and my playing around a bit with Range vs. Standard Mode on the HVAC, I've been charging to 80 or 90% again because the cold weather is using a fair bit more energy. Not exactly "range anxiety", but I do start to notice it when I get down to 20% or so SOC by the end of the day.

I've been taking the same approach. The power consumption jumps significantly between +3C and -3C. Also battery degradation is accelerated when the cell is at high charge AND high temperatures. Since it's now colder, charging the car to a higher level will have significantly less impact.
 
I don't think the damage from regularly charging all cells to 90% is less than leaving it out of balance at 50% or so. Yes, the out of balance cells will be stressed slightly more, but it's still at relatively low SOC (so not overly stressed).

Do we have confirmation that balancing even occurs when charging to 90%. I've read in several places that it only balances when you charge to 100%.
 
Do we have confirmation that balancing even occurs when charging to 90%. I've read in several places that it only balances when you charge to 100%.
I can tell you from experience that it occurs on the Roadster at 90% (Which is a Standard mode charge - we don't have the variable slider like on Model S). I don't think anyone has gained access to the diagnostics screens in the MS that shows balance state. If you have a severely out of balance pack (some folks who had batteries replaced by Tesla got out of balance packs) it will balance faster (fewer charge/discharge cycles) at 100% but it is harder on the battery. For normal use just charge to 90%. It would be interesting to get confirmation from Tesla if balancing occurs at lower SOCs but I am confident it occurs at 90%.

On a related note I have had my Roadster for 3 years and 33,000 miles. It is my daily driver and charged to Standard mode (90%) every night. I have lost 5.8% of my capacity.

So as I said above, if you have a bunch of time on your hands and take pleasure in geeking out to this stuff, by all means call it a hobby, geek out, and spend a bunch of time finding the most perfect battery maximizing system for your application. But for 98% of owners just charge it every night and drive the thing. Tesla knows how to take care of their batteries.
 
On a related note I have had my Roadster for 3 years and 33,000 miles. It is my daily driver and charged to Standard mode (90%) every night. I have lost 5.8% of my capacity.

As another data point, my Roadster has similar age and mileage and is also my daily driver. I charge once or twice a week, running between 50% and 35% SOC during the week and taking it up to a Standard charge for the occasional weekend. I've seen no degradation over the past three years. Standard mode still charges to 300km and CAC is 156.

I agree the difference is marginal and both batteries will probably last longer than the lives of our cars, but for me there's no extra effort to run at a lower SOC during the week and it still gives me more miles than I'd ever use in a day.

If anything, I think I'm being lazy rather than OCD by only plugging it in once a week. :smile:
 
One problem with choosing a daily charge level less than 90% is that the smartphone app will set it back to 90% each time you initiate a Standard charge from the app.

I like that behaviour because I can set it to less, then before I leave use the App to switch to Range and then back to Standard. That way if I'm delayed for some reason, it never goes past Standard and I have a warm battery when starting.
 
Yes, 50% on weekdays and 90% on weekends is better for the pack than keeping it at 90%. You'll have a lower average SOC but still have a chance to balance on weekends.

If you allow (make a habit) your pack to sit for 1/2 to an hour after a charge (so it may balance) there's no need for the pack to be sitting @90% over the weekend. The pack will already be in balance, doing partial charges and not allowing the pack to balance throws it out of whack. I do a std. mode charge on my Roadster during the week, @9am my pack is done charging, I allow it to sit for 1/2hr to balance, then I drive off pulling the SOC from 84% down to 74% where it sits until 6-7pm in a parking garage. Then I drive home where my SOC is now at 64%. The Roadster charges @6am again, done @9am, and again I drive off at 9:30am. The weekend sometimes I don't drive much so I'll keep the SOC at 50-60% for those two days. I'm always targeting 55-65% SOC.