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Cottonwood
Roadster#433, Model S#S37
Here is the plot of the power drawn from the HPWC during a "last 10%" charger with a max at 20kW. Ignore the steps up and down that is me playing with climate on/off to preheat the battery and cabin as much as possible before a winter hypermile adventure. Just fill in the lower curve line for power used to charge; the rest went to heating.
The answer is about 2 hours to charge from 90% to 100% with the taper. You can see that it only stayed at 20kW for about the first 5-7 minutes before the taper started.
^^
this will be different with different temps but more so if your battery is well balanced or not
I tried to show it here:
balancing taper for 3 - 100% charges
-Charge-Taper-balancing-graphic
this will be different with different temps but more so if your battery is well balanced or not
I tried to show it here:
balancing taper for 3 - 100% charges
-Charge-Taper-balancing-graphic
mknox
Well-Known Member
To be honest, I'm unclear on what the exact process is to balance the pack, but what I can tell you is that I let the 100% charge complete until it stopped, and the last bit took a lot longer than the time it took to get to 95% or so. I am assuming that long stretch was it "balancing" the pack. So if that is, in fact, how you balance the battery then yes, 245 miles after balancing.
bbamrah
Member
I have a car almost a year old P85 90% charge gives me 217. I figured it was all related to driving habits and temperature. It really doesn't matter to me what rated tells me I assume only 160-170 miles with the way I drive and this horrible winter we have had. Working on hospitals I work at to install chargers. I commute up to 150 miles a day.
I was chatting with my Tesla Service Advisor this past Saturday as my car was getting some work done. We had a conversation about battery balancing and I told him that I wasn't sure about the previous information he gave me about balancing (that the BMS balances at any SoC). So he did some research while I was waiting and came back with:
1) balancing only happens at the top of a range charge (that's not technically 100% charge).
2) CAC recalculation only happens on a deep cycle.
Not quite sure what deep cycle really means in this context - as in how deep is deep enough, but I assume it's drive to almost zero. Which means you have to do both a range charge, drive to near zero, and then a range charge to get a sense of exactly what your battery can still hold. I suspect that the second range charge is probably best done at a moderate rate (ie. Supercharging might not be best).
So I take it to mean that occasionally, it's a good thing to run it all the way down and charge it all the way up.
1) balancing only happens at the top of a range charge (that's not technically 100% charge).
2) CAC recalculation only happens on a deep cycle.
Not quite sure what deep cycle really means in this context - as in how deep is deep enough, but I assume it's drive to almost zero. Which means you have to do both a range charge, drive to near zero, and then a range charge to get a sense of exactly what your battery can still hold. I suspect that the second range charge is probably best done at a moderate rate (ie. Supercharging might not be best).
So I take it to mean that occasionally, it's a good thing to run it all the way down and charge it all the way up.
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mknox
Well-Known Member
Interesting. I'm not sure I've ever run mine down below about 40% SOC. In the winter, I charge to 90% and return at the end of the day at or slightly above 40. In the summer I go from 70 or 80 to about 40 or 50.
Most battery strategies (other than for cars) talk about running the battery between 20 -30% and 80% and then every 10th charge or so doing a deep discharge and full charge.
I know they want you to plug it in all the time, but should that be - drive 8 miles to work, plug in, drive 8 miles home, plug in, etc? Is there a way to - and would it be better to - plug in but Not ADD charge until you dip down sufficiently.
Ok if you tell me I am still over thinking this ...
I know they want you to plug it in all the time, but should that be - drive 8 miles to work, plug in, drive 8 miles home, plug in, etc? Is there a way to - and would it be better to - plug in but Not ADD charge until you dip down sufficiently.
Ok if you tell me I am still over thinking this ...
I think basically set it to what is comfortable for your daily range + side trips + at least 30% margin in the winter. You can use a far lower margin in the summer, depending on your driving habits. For most people, that's probably between 50% and 80%. Then, don't worry about it. Every couple of months or three, range charge and drive that day. CAC re-calculation is a cosmetic issue, so if it bothers you, then drive it all the way down on a road trip at some point.
You are still overthinking this. Just plug it in every day when you get home, and enjoy the car. The beauty of Tesla is that you DON'T have to think about the battery, it has software to manage the battery and the software is designed by people who know more about it than any of us do, no matter what we read about strategies for other batteries. Try not to run it to zero, only use range charge when you're going out of town, and don't become one of those people who obsess over their battery state of charge.
Agree 100%. Tesla is the first company to make an EV where the owner doesn't have to pay much attention to battery charge management. Just follow a few simple guidelines as described above.
+1
@plbeic
My car was delivered with charge set at 92-93% ("Standard" charge). After a few firmware releases this changed to 90% ("maximum Daily charge"). I'm at 23.6k miles, have never changed this setting, and plug in nightly. Keep it simple, and enjoy the ride.
huntjo
Member
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