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What should my ideal charge percentage be?

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Doesn't the car still display a warning, that requires authorization, when setting it to Trip/Max range? Haven't tried since going to .61.

I'm surprised we now have 11 pages of discussion on this topic, but I'm happy to geek out and say this: We only charge the amount that we'll need the next day and sometimes plan on charging at our "close-by" destination. My supposition is that we'll put the batteries through the *least* amount of stress and charging cycles by allowing the range to not fall below 30 miles (only on rare occasions or trips) overnight or even for a few hours, but also not charging to any more than what is needed in a given day. This has worked out well so far and when we do range charge we are still seeing over 200 miles (60kWh) rated and are nearing 10K on the odometer (hard to guess but guessing 1 to 2% degradation) and 7 months of ownership.
 
On my new S85 running .61, I'm getting 236-239 rated (239 right when its complete, dropping down over a couple hours) on a standard charge. I set it to 80% last night, and I got 203.3 rated. 239 makes sense as 90% of 265, but isn't 203.3 a little low for 80% of 265 (212)? I wondered if it went into some of the funny math here (Sign into My Tesla | Tesla Motors) but still couldn't really make sense of it. What do you guys think?
 
On my new S85 running .61, I'm getting 236-239 rated (239 right when its complete, dropping down over a couple hours) on a standard charge. I set it to 80% last night, and I got 203.3 rated. 239 makes sense as 90% of 265, but isn't 203.3 a little low for 80% of 265 (212)? I wondered if it went into some of the funny math here (Sign into My Tesla | Tesla Motors) but still couldn't really make sense of it. What do you guys think?

This sounds exactly consistent with the forum thread that you link to. I have a couple longer road trips ahead and have my server setup to log all the telemetry data, that should help figure out SOC to range ratios (especially as the second trip should be quite a stretch for my S60). I'll post an update once I was able to analyze the data.
 
On my new S85 running .61, I'm getting 236-239 rated (239 right when its complete, dropping down over a couple hours) on a standard charge. I set it to 80% last night, and I got 203.3 rated. 239 makes sense as 90% of 265, but isn't 203.3 a little low for 80% of 265 (212)? I wondered if it went into some of the funny math here (Sign into My Tesla | Tesla Motors) but still couldn't really make sense of it. What do you guys think?

Michael - I regularly get 204 miles on an 80% charge on my P85. Of course, the vampires begin to eat away at that over time.
 
On my new S85 running .61, I'm getting 236-239 rated (239 right when its complete, dropping down over a couple hours) on a standard charge. I set it to 80% last night, and I got 203.3 rated. 239 makes sense as 90% of 265, but isn't 203.3 a little low for 80% of 265 (212)? I wondered if it went into some of the funny math here (Sign into My Tesla | Tesla Motors) but still couldn't really make sense of it. What do you guys think?

I don't think the slider percentages and Rated Miles are linear. See my observations here.
 
The Superchargers being installed in my state are making me rethink my slider level.

As has been mentioned several times, there's a balance to be considered. Too much charge, and you might accelerate battery degradation. Too little charge, and you might not have what you need some day. I set my slider at about 80%, but was reluctant to go farther - after all, the degradation should be awfully small; but if you ever find yourself without enough range, man that will really suck (at least for people without a gas car for a backup). I use a 14-50 at home, so I can't fill up very fast.

It was mentioned before that a nearby Supercharger would change your thinking. You could just leave it at 50% all the time; and if you have a sudden need to take a trip, hit the Supercharger. Of course, few people will have a Supercharger nearby.

Lately I have been considering that if they are placed well, the Superchargers don't have to be nearby. Right now there are Superchargers on the main highway going North and South of me; and in a few months there should be one to the East. They are 60 - 100 miles away; not exactly convenient for a local fillup. But, what if I just keep my battery at, say, 160 miles? For any trip that doesn't go as far as a Supercharger, I should be able to make it there and back without charging. And if I suddenly find I have to take off on a longer trip, I can make it to the Supercharger in any of those directions even after a normal day's driving. True the Superchargers are not along every highway, but any direction I can imagine having to go (as opposed to many I might want to go on for recreation; we are not that spontaneous) could reasonably pass one; things are just laid out that way here.

This obviously depends on both Supercharger distance and location; but when done right (and I think they are for Seattle) an 85kWh owner can knock their slider down quite a ways and still be able take off at a moment's notice. I know we can all still come up with unusual scenarios where it won't work at any given level, but I still feel a lot better about keeping my charge level lower. I think I will be comfortable using 60% once that Supercharger to the East gets put in. It's my wife's car, so I'll have to convince her first though.

Superchargers are kewl.
 
@ChadS
There are some "geography inconveniences" with WA though. Something to keep in mind. For example, a round-trip to Bremerton from the Bellevue area is not helped by superchargers and can't be handled adequately by a 160 mile charge. Especially, if you want to actually use some juice in Bremerton while you're there.

Note that I'm referring to the "non-ferry" route. I don't like ferries in my large vehicle. (Also, I don't like having to coordinate with a ferry schedule.)
 
We only charge the amount that we'll need the next day and sometimes plan on charging at our "close-by" destination. My supposition is that we'll put the batteries through the *least* amount of stress and charging cycles by allowing the range to not fall below 30 miles (only on rare occasions or trips) overnight or even for a few hours, but also not charging to any more than what is needed in a given day. This has worked out well so far and when we do range charge we are still seeing over 200 miles (60kWh) rated and are nearing 10K on the odometer (hard to guess but guessing 1 to 2% degradation) and 7 months of ownership.

The Roadster study done by Plug-In America projects that Tesla batteries will still keep 80% or so of their original capacity after 100K miles, so we should all expect to see "full rated" capacity for a long time yet. Seeing anything significantly lower should be a sign of concern.

Overall, your charging methodology sounds like you're willing and happy to put in some extra work to keep you battery as healthy as possible. If so, then I'd suggest you modify it to make that lower reserve at least 40, IMHO ideally 50 rated miles. The 60 KWh battery has a full rated range of 208, so 40 rated miles of reserve is roughly 20%. Avoiding the 0-20% range and the 80-100% range is most likely to lead to a long life for your battery from what I've read.
 
Assuming a full rollout of the SC network, with stations every 140-150 miles on the Interstates, is it ever advisable to SC to 100% of a battery's capacity? I've always assumed that SCs have just too high an amperate/voltage figure (250 amps/400v?) to safely SC to 100%.
 
Define "safely".

I care for my stuff as well as I reasonably can. But (a) this is a car, and I need to drive it, and getting safely to where I'm going is my first priority; plus (b) 150 miles between Superchargers is just perfect for getting me from one to another (based on 100% charge leaving the last Supercharger) with spirited driving and a good reserve in an 85, or with moderate driving and a good reserve in a 60. If I'm on a road trip, I'm going to SC to 100% every time. :)
 
Supercharging slows waaay down as the battery fills, so it should be safe. The main downside is that it just takes forever. Once the superchargers are every 140-150 miles, you'll probably want to charge up to 170-200 depending on driving style and battery size.
 
The emperor has no clothes

Michael - I regularly get 204 miles on an 80% charge on my P85. Of course, the vampires begin to eat away at that over time.


Every 24 hours I lose 3.5% of my maximum P85 charge. If I keep my P85 at 80% charge (66 kW) I lose 4.5 % everyday. And every day my main battery drops, I lose even a greater percentage. And on the day I have 10 kW in my battery, I lose 33%. And the next day, with 7 kW left, I lose.................. my main battery.

Vampire loss is a big deal. IMO, vampire loss needs to be fixed sooner rather than later. I have the luxury that I can plug my MS in every night in a insulated garage.With winter arriving, vampire loss combined with kW needed to keep that main battery safe and warm makes the long term health of the main battery from losses a looming threat. I will have no choice at what level to charge at 0 degrees in January. The only option will be at 90%. And I will need to preheat the MS cabin before I leave and to keep the main battery warm at 0 degrees ambient temp when I arrive at my outdoor parking spot. At night many users will have to adjust their charging rate (amperage) at night to both heat the main battery while charging and to completely recharge their battery at 0 degrees to coincide with when they leave the house at 6 am on a frigid Wisconsin morning. This is not a user friendly end state.

The above scenario may not be a big deal in Northern California, but it is a big deal in many other parts of the country that get seriously cold in the Winter. TMC needs to get vampire losses fixed now, not in January when owner concerns start surfacing.

NOW is the time for TMC to start fielding the firmware solution, not in 4 months. Testing hibernation/sleep mode now will give them the opportunity of not bricking a main battery.

I can see the MS choosing to program a warning to the owner via the 17 inch center stack that it is 0 degrees outside and the center stack stating in big red letters, "plug in and select hibernation mode". Or automatically select hibernation mode if the end user does not do it just to protect the main battery.

I would rather have my MS take a minute to wake up at 0 degrees than not to wake up at all from a bricked battery.

As I mentioned, I have an insulated and warm garage. My garage never freezes. I am lucky. I can wait. Some users to do not have my setup.

This is the 800-pound elephant in the room.
 
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Supercharging slows waaay down as the battery fills, so it should be safe. The main downside is that it just takes forever. Once the superchargers are every 140-150 miles, you'll probably want to charge up to 170-200 depending on driving style and battery size.

From Supercharger | Tesla Motors:

SC Charging.png


I have been looking at this a lot, because my house in SW Colorado is just at the edge of range from Silverthorne, CO. When the Silverthorne, CO Supercharger comes online, it looks like I will just have to plan on a 45 minute or so coffee/shopping break to get a full charge after driving to Silverthorne from Boulder. That is still better than 3-4 hours at an RV park! The other way it will be a very quick stop.
 
UPDATE DIRECTLY FROM TESLA!

I spoke with Brent at Ownership today. He told me that the ideal charge level is 50%-62% in order to best minimize long term capacity loss. That pretty much lines up with the recommendations made in this thread. I had originally felt that Tesla's recommendation was probably good enough, but now that I actually own the vehicle I'm more concerned with protecting the battery asset. Given that this is all pretty new technology, I would like to do what I can to minimize wear and tear over the long term.

I did not want to follow the protocols recommended here if I did not at least confirm with Tesla that keeping the car at these lower charge states would not harm the battery versus keeping it at 90%. Now that I have confirmed with the Tesla that 50%-62% is best, I will be keeping the car at 50% charge and will add range just prior to driving the car for that day. Brent said that if we don't mind jumping through these hoops, we are doing the right thing. However he did qualify his statements by saying that Tesla feels any gains by keeping the battery at a lower state of charge would be "negligible".
 
@Amped - is Brent a TM battery engineer? We've seen all kinds of random info from TM over the years. Is there something that gives you faith in what he says?

Exactly. Common sense tells me that since Tesla lets you charge it TO 50%(used to be 30%), that the optimum level is much lower than 50-62%. That and all of the battery studies and tests point to a 20% charge as the best case SOC to keep the battery at(what roadster storage mode uses). This is not rocket science.
 
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Exactly. Common sense tells me that since Tesla lets you charge it TO 50%(used to be 30%), that the optimum level is much lower than 50-62%. That and all of the battery studies and tests point to a 20% charge as the best case SOC to keep the battery at(what roadster storage mode uses). This is not rocket science.
So what you are saying is "program your charge every evening so that the car is at 50% by the time you leave the next morning (but no earlier) - and only charge higher if you need to" ?
 
So what you are saying is "program your charge every evening so that the car is at 50% by the time you leave the next morning (but no earlier) - and only charge higher if you need to" ?

It depends on how much you drive. If you drive very little, then yes, that will be the ticket. SOC also matters less when it's cold.