My midrange M3 started at 264 miles the first few full charges 1 1/2 yrs ago. With around 19,000 miles, I seldom charge above 90% (220 mi) when using my home Tesla charger. I recharge a couple times a week. Very seldom do I use a Supercharger unless I'm traveling outside the range. When I do charge to 100%, I get into the 240s. So I'd assume I'm not having the same issues and I run Sentry ALL the time because my car sits outside 24/7. How would I assure the car "sleeps" for hours at a time other than shutting off Sentry and the 105 degree protection? It would be interesting to see if I could recover some of those "lost" miles.
Thanks to the OP for the great post. I just got back from a 12,000km / 7,456 mile road trip. I’m now at 107,220 km’s or 66,623 miles. I had sentry mode on 24/7, but had many days where I drove over 3 hours straight. I’m sitting at 5.4% loss after my return. I was around 6% when I left. Maybe the car did some calibrating when I was away. Again, thanks for the post.
Re vampire drain - I thought the 3 was generally worse than the S/X in that regard, not better? (lots of articles but example at Tesla Model 3 "Phantom Drain" compared to Model S and Model X). Tesla also generally seem to be much worse than other manufacturers in that regard. I almost never use Sentry Mode as the vampire drain with it is brutal compared to when it isn't enabled. I don't have home charging so I already leave the car at various SOCs for hours and days at a time and I'm still seeing a slow, continuous reduction in TeslaFi - maybe it would be more marked if I left it plugged in, I don't know. I hope it levels out going forward...
Superb post, so pleased i found it. My SR+ has covered 7700 mile in 9 months and the range has dropped from 234 to 212, nobody could explain why ... Tesla said it must have been a software update that has caused some cells to misreport their capacity, yet every time there's a software update my range drops again. My journeys are are all very short and i charge to 80% every night. Trying the theory out on this one.
Can't say I'm super impressed with the battery. I'm at 12000 miles now and down 20 miles. I was told 5% loss is normal withing the first 12000 and then about 1% every 12000 miles but I'm constantly seeing the battery losing capacity.
I can confirm that from my experience. I think it comes down to Tesla choice of cell chemistry and approach to relatively tight battery management. My S spends far more (in my case wasted) effort balancing, heating, cooling, reducing regen etc than my little Renault EV that pushes the battery far less but doesn't need to fuss with it either. But the Renault is only an adequate means of transport.
FYI the wiper control is on the left stalk, just press it in . You don't need to take your eyes off the road.
This idea really is for ostriches. Head in the sand and all's well. If you are that uninterested in your battery health then not much point reading information posted here. Ah, you must be driving faster, on flat tires, have the a/c on higher with colder outdoor temps. Or your battery could be loosing capacity / useable capacity through multiple processes.
I keep an eye on the estimated percent SOC at the destination (next charger). If it drops below 8% then I slow down.
OK, I too am a senior, cruising along in my ninth decade, and I love my M3. You don’t have to do things the way you describe. Want to open the glove box, use voice command and say “Open the glove box.” BINGO! Want a quick window clean, press the button on the end of the steering wheel stalk. VOILA! Want to turn on and/or adjust windshield wiper speed or increase/decrease car temperature or fan speed, or turn on the rear camera, voice command will do it. Does a bunch of other stuff as well. My M3, along with everyone else’s, has become increasingly easy and far less complicated to drive. At first, it’s a bit intimidating because it’s so different from an ICE vehicle, but it’s a very quick learning curve, and I think it’s a great car for seniors—if they install the updates and take advantage of what they provide. Don’t understand why you don’t know this, but I still enjoyed your post. Hope you read this after your nap.
As an Electrical Engineer, I would think you would better appreciate the value of calibrated instruments. Sure, the readings are not perfect, but the Tesla Guess-O-Meter is WAY better than my old Chevy Volt's meter, mainly because Tesla knows the route you're taking and elevations along that route. Another thing I would like you to clarify for me ... You are the 1st person I've seen to state that leaving your battery charged to 100% for days or weeks up to a month is not harmful. (!) On what do you base that claim?
In a few threads up, you suggested that setting visuals to %, means you have your head in the sand when it comes to battery health. I set my visual to %, and not KM’s/Miles, because I took the time to understand how the battery works, what is good for it, what is bad for it, and I know that when it shows a given (__)% (SOC) loss, that doesn’t necessarily mean it has that actual loss.. Suggesting that folks heads are in the sand if they chose %, suggests your understanding of why they chose it, and perhaps how much you know about the BMS is presumptuous, and weak.
Your experiences matches mine, I lost about 10% on my AWD range with only 18000km and 10 months of life, to get something baxk I tried: Setting max charge from 80 to 90 Discharge the car to 10% supercharge to 100 all in one drive This give me about 5-8km back, so nothing worth it. Then somebody pointed to me that my car only had 18000 but since I used sentry about 10h/ day at work that my battery had a bigger use and tear so I did this: - I let the car discharge down to 10% in several days at about 20% discharge per day and then charge it back to 90% at home, no supercharging, and leave it at that for several hours - Stop using sentry at work Then I gained almost 20 km back up and it’s been like that since. I started my experiment with 448km Max range and I’m now at 468, still far from my 499 when new but I started today another slow discharge of 20% per day and see what happens
Thanks for the interesting and thoughtful post! It is substantial food for thought. I kind of doubt this. What is the value of the bleed resistor? Once we know that we can calculate, though... I guess it is possible that vampire drain (*after rebalancing is complete*) is actually very low on Model 3, but it certainly is hard to determine. My best estimate is around 40W average in an optimized state, but that is derived after a brief period of sitting, and perhaps after longer periods of sitting the average is lower (again, difficult experiment to perform repeatably). The other comment I would have here is that once the balancing is complete, they don’t bleed anymore regardless of the resistor value, do they? Once the battery is balanced (all bricks at same voltage), there isn’t a need to bleed. So I could see a smaller resistor value leading to greater short term vampire loss (quicker rebalancing), but as far as longer term vampire loss is concerned I can’t see the resistor value as mattering. Originally you had 78-79kWh. This is actually 290*245 = 71kWh And 270*245 = 66.1kWh So you recovered from ~15% loss to ~9% loss. This is still substantial recovery, of course. How would you explain calibrated charging interval experiments showing shorter charge intervals on cars showing loss of capacity? In general, you can estimate charge times within a few minutes. This indicates that the estimates of capacity are close to accurate. Every time we have really dug into it with calibrated charging experiments here (we know what the charging overhead is from the EPA documents and also from other methods), the car’s estimate of energy available appears to be within 1-2% of accurate. Still, interesting. I’ll try leaving my car sitting at a low charge for a few hours a couple times over the next week. I really need to measure the discharge energy on the car meter as well from a high SoC - haven’t done that in a while, and now that capacity is degraded it should show a lower value for how much was used for a full discharge. (As we well know, the discharge energy does not capture all the energy used (off by perhaps 1%) - I can’t compare that value to the charge event or the BMS estimate. I’m just talking about comparing relative to my prior discharge events.) To me it seems that charging event energy and discharging event energies both point towards the BMS rated miles estimate as being an accurate assessment of energy available. But, if that is true, I am curious about exactly what happened within your battery that made more energy available over time! 15-20 rated miles is quite significant! Are you sure the 270 at 100% was not measured at a time when the battery had insufficient time to balance? I could see doing a charge to 100% and then immediately driving. This would lead potentially to a result where your 100% was limited by the voltage cap on your weakest brick (since it would max out soonest). If the battery had been left at that state, of course it would have bled down that brick and then started charging all bricks in series some more - which would have resulted in more energy available than 270 rated miles. To me that’s the first idea that comes to mind for how available energy would go UP in a battery over time. I assume it is not self-healing! And we know capacity loss in general is real, as the battery has various deleterious physical mechanisms by which it can hold less energy over time. So what was the exact situation on the charge to 100% (you said the 270 was not an extrapolation, I think - obviously we ignore any extrapolation data points for this discussion)? Did it sit overnight or for 10-24 hours? Or did you charge and then go?
You are correct that I was / am making such an assumption, and it is based on most of such advice has been followed by "..... and then just don't worry about it." Of course, if you get what's going on and are watching for changes in percentage after consistent journeys etc, then you are clearly making the call based on understanding. The 'head in the sand' comment was based on very different situations and in the absence of clear, concise and accurate posts such as the op of this thread. I think it is important to keep in mind that there are two very different issues. One is if a vehicle is accurately reporting its maximum range, and the other is how an owner would see real loss of capacity in the battery.
That is painful for long distance road trips where you just make it to a supercharger on low battery SoC and immediately start high speed charging. Some people even suggested to stretch out stops to more distant superchargers to arrive with lower SoC so that you get the higher current charging that comes with lower battery charge states. (Car supercharges more rapidly at 20% SoC than at 60% SoC for instance.) This is part of some tradeoffs of convenience (less time waiting at Superchargers) vs battery care for longevity. Given the option to stop more times and accept slower charging from higher SoCs, I would tend to pick that to be nicer to my battery instead of letting it drain down to a low battery charge state.
So, to me, that is another trade-off. It sounds like you could be slowly degrading your battery more so that you can get better capacity readings from the BMS. I tend to try to keep my battery in the 40%-80% range nearly all the time and only go above or below for a rare long distance road trip. Personally, if I felt my range indicator was to drift too far from (what I think is) battery reality, I would do a one time skip on charging, and one time charge to 90% just to get more readings, but I wouldn't make it a habit of letting it get down to 20% on a regular basis.
This is way off topic...so will be my last comment on this...but: I don’t know that there is any evidence that charging at 250kW at 10% SoC is any more stressful than charging at ~170kW at 40% SoC. For all we know 250kW at 10% SoC may be less stressful. All depends on how fast those ions can diffuse I think? So I’m not sure that following a non-optimal charging strategy on a road trip to attempt to preserve the battery is actually helpful for preserving the battery. A better strategy for battery preservation (which undoubtedly IS less stressful) might be to avoid V3 Superchargers I suppose. But the V3 have the distinct advantages of being much faster, and also actually working, for now (many V2 Superchargers are broken in my experience - providing ~118kW rather than 150kW, for example - about 50% of the time I have to move stalls to get a higher rate). You could additionally search out partially broken V2 superchargers to further preserve your battery (it’s usually not hard to find one that will charge at 30-72kW, if you try them all). The overhead in searching them out doesn’t matter since time is obviously not a factor. Of course, going immediately to a shared charger with another vehicle is another winning strategy here (probably would annoy the other driver though). I would have had a harder time driving from San Diego to Portland in a day without V3 Superchargers. Possible still (assuming the V2 were working properly), but the V3 sure are nice. 1076 miles at an average speed of 58mph! (~18.5 hours). 4:10AM to 10:40PM