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How low have you gone?
- Thread starter Pinot.Noir
- Start date
No, you're wrong because you're thinking of something else and didn't understand what @jelloslug was referring to. The question was about whether the battery going totally empty was harmful to it. Here was the question from @Pinot.Noir :
"Isn't it bad for the battery to run to zero?"
Lithium ion batteries do suffer some pretty bad and permanent damage if they actually get run fully empty. This is like can't recharge them, can't use them type of damage. What @jelloslug was explaining was about what is usually referred to as the "anti-bricking reserve". The cars are set to completely shut themselves down with about 4 to 5 kwh left in the battery to save any of us Tesla drivers from accidentally destroying the batteries in our cars. That is what he was explaining, how the number zero on the miles display is not actually zero energy in the battery. There is a bit of actual energy in the battery there that Tesla keeps permanently hidden and inaccessible.
That is different than this other thing that you're talking about where above the safety shutdown point, the zero miles estimate sometimes isn't exact. You can sometimes get a few more miles beyond the display number before the car shuts down.
DB 2
Member
I think (almost) everyone on this thread interprets "run to zero" as "run to zero miles" (or km) on the instrument panel.
If the pack is taken to zero volts, or whatever qualifies as 0 kWh of total remaining capacity, the pack will be ruined. The car won't let you get anywhere near that point by doing the mandatory pack protection shutdown at or near the 0 kWh usable remaining energy point as calculated by the battery management system (BMS). However, the driver doesn't know what the BMS has calculated. The driver only knows 0 miles on the dashboard. I think you imply later in your post that you believe that 0 miles on the dash and BMS-calculated 0 kWh usable remaining energy are the same point (or at least very close). I have proven that (in my car at least) this is not true. Zero miles on the dash is 3.8 kWh usable remaining energy according to the BMS. And it is usable, because I used it. And took photos. And posted them.
I agree that the BMS remaining energy figure is an estimate, but, at least in mild weather with a warm pack and gentle use of the accelerator pedal, it seems to be accurate +/- 0.1 or 0.2 kWh. I highly doubt it is ever off by 2 kWh, never mind 3.8 kWh.
Maybe my car is a unicorn, but somehow I doubt it. Other models may well have different size cushions, but if anyone can show (using current firmware) a cushion less than 2.0 kWh, I'll eat my hat.
How do I go about getting this app? I can't find it on the Google Play Store.
As I understand, the battery has 14 modules, totaling 61kwh and 58.5 usable kwh. If my 100% is around 275-280, and the rated range is 178wh/km, then it would suggest I have 49 - 50 kwh of usable capacity. A loss of 8.5kwh.
The S 60 has 14 modules? Meaning each module has about 4.35 kwh of capacity. Could it be that I've got 2 bad modules? How would the car handle a bad module?
is it bad for the battery to have a bad module or can it handle fewer modules fine? I figure one could simply replace a faulty module but then the new module will be a completely different age to the old ones.
Any suggestions for a guy with no access to a Tesla Service Centre?
Can you clarify this for me?
Okay so if we look at a 2014 s 60, the battery itself should have around 61kwh of total capacity, of which 58.5kwh is 'usable'. So are you saying when the indicator shows 0 miles remaining, there is actually around 3.8kwh of remaining USABLE battery? Meaning if I start with a 100% charge, and run down to 0% (as displayed on the dash), it mean's I've only actually used 54.7kwh (or thereabouts)?
So the 0 - 100% is more like 10-100% and the bottom 10% is just completely hidden (2.5kwh left for anti-bricking and 3.8 for buffer?)
jelloslug
Active Member
You can see the difference or buffer with TMSpy. If you have your battery % shown on the dash, and look at it with TMSpy, it's usually 3 to 5% difference depending on the pack size.
0 to 1% on a 75D still has 4% remaining.
1% remaining on a 15 85d still has 5% remaining.
Lasttoy
Active Member
I think I will buy generator for insurance, I got to 10 and was scared to death.
Mother tesla told me yesterday, never leave car in airport for more than 5 days or it will be dead meat.
Mother tesla told me yesterday, never leave car in airport for more than 5 days or it will be dead meat.
Can't tell if you're kidding or not, but don't just buy one assuming it will work. Most generators will NOT work to charge a Tesla. The Tesla charging cord is particular about having a real ground connection, and the vast majority of generators out on the market don't have one. Search this forum or the other one at Tesla's site for information on generators and which ones may work.
No, that's not any problem. You can go a few weeks, and it will only lose around 1 or 2 miles a day IF (pay attention here) you don't keep checking on it. The car will go into a hibernate/sleep kind of low power mode within about the first 24 hours and I think a deeper sleep mode within 48 hours. But if you're running something like TeslaSpy or one of those other remote monitoring utilities that's always poking the car every few minutes for data, it's basically keeping the car awake and using more energy, and it can never go into those power saving modes. The same goes for not connecting to it with your phone app every day to check on it too.
EV-lutioin
Active Member
6 miles... I planned to stop at the Corning Super Charger on the way home from the mountains to get a little boost, but the road across the Sacramento River was closed due to flooding. I took it easy (into a strong headwind) and got her home with six to spare 
)
)
DB 2
Member
Yes, that is what I'm saying (all numbers approximate, not exact) with one BIG caveat: I don't know that the classic S60 uses the same 3.8 usable buffer that the refreshed 60/75 does (or at least mine). The differential between your Wh/rated km while driving versus on the graph is about right, but without seeing BMS data I would not call it conclusive.
Also, there is reason to suspect that this usable buffer below zero km has been changed over the various firmware versions (probably more than once). So, if you are using non-current firmware (some owners of pre-Autopilot cars have avoided updates), my confidence would decrease.
DB 2
Member
Getting and using TM-Spy is discussed here and also here (including the link to expose it on Google Play).
The idea that you might have a bad module also occurred to me. I would think the car would recognize it and report to Tesla HQ and even on the car's displays, but I have no actual knowledge about that. I also have nothing intelligent to say about any repair/replace issues except that I hope they would do it under warranty and give you a loaner pack during the interim.
I do believe that if there is a localized defect in the pack rather than general degradation, TM-Spy would likely reveal it clearly.
I can't remember the exact number version right now, but people did track down exactly what firmware version that not just "changed", but eliminated the below 0 driving buffer. It was in the 5.x series somewhere.
GlmnAlyAirCar
Active Member
That's a pretty broad statement. The 4kWh brick buffer is there precisely to prevent this kind of damage. I'm not suggesting that going down to 0RM is completely safe, but there is no evidence I know if that indicates running this low damages the battery.
DB 2
Member
There have been many firmware versions since 5.x, and therefore many opportunities for Tesla to put it back. My guess is they got tired of people having a shutdown while still showing a few miles of range remaining, and then arguing that Tesla should pay for the tow.
You use the past tense there like it doesn't happen any more, and I don't see why. There continue to occasionally be reports here on this forum of cars shutting down with a couple of miles range still showing.
I'm the nervous type. If it was an ICE, i don't mind walking to get some gas or call AAA. But since it is battery, that isn't as easy. So when I plan my route, i try to at the very least leave 20 miles contingency and that is the lowest i've done.
I'm intrigued by that - in the first place because in my experience, since 2013, range is on the one hand optimistic (you need to add 20% or 30%) but on the other hand predictable - if you're e.g. consuming 120%, it will stay that way (all external things being equal), and not suddenly go berserk, so indeed you can go down to 1km or even 0k by sticking to the 120% or 130% "rule".
Does anyone have an 'anthology' of reports of the car shutting down with a couple of miles still showing?
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