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I have a MS P100D on loan for a few days to give me the opportunity to test it in my regular use. The "P" is just because that was what was available.

My one-way, would normally be non-stop, journey used 75% of battery in total. This is more than I'd hoped it would because I do the same journey twice most weeks so I want to do it in the charge range of minimising battery degradation over time. When I get one I'll probably do this in the same car for well over 100k miles, maybe even 200.

There are mitigating factors - the new cars are supposedly 10% more efficient and a non P car quotes 3% more range than P. I calculate those changes to take my charge used down to 65% like-for-like.

I could (should?) drive a bit slower. Perhaps the biggest effect even if it's only a little slower, but I can't quantify it. I should've done this for the sake of my experiment but the roads were clearer than my usual travel time and I was having a little too much fun.

There's a supercharger en route half way, but the coffee there's *sugar* (*sugar* coffee may be the worst downside of EV life, is a starting hypothesis I have - I'll have to drink more tea). There will also be good home/work charging at either end so the battery can start warm.

However there are also the negatives of battery degredation over time and the effects of cold weather, which I think could outstrip my above errors the other way. 12°, clear, dry and moderately windy yesterday evening.

Keen to hear the thoughts of you experienced owners on this.

Would you consider regular charging to 90% to be much worse for your car than 80%? Would you consider running it down to 10% so regularly to be similarly poor form?

Would you expect a 5% motorway speed reduction to knock say 10% off your power consumption?

What sort of percentage effect would you anticipate from moving from sport to chill and range mode (which I only did for the slower half of my journey)?

Overall I think I'm in a decent place here, but I'd like a buffer and to treat this expensive battery with care.
 
IMO you are perhaps giving the battery to much consideration, it is there to be used. There is no problem charging to 100% on a regular basis providing you aren’t letting the car sit there for ages before driving. Similarly, running the battery down to 10% or lower isn’t a problem, it’s when you leave it like that the trouble can start.

You didn’t say what speed you were driving at. Range begins to really suffer post 70ish mph. At 80mph you use massively more energy than the modest percentage increase in speed would suggest. I think it’s something like 4 times as much at 80mph than 70mph.

Range mode restricts the HVAC system and I’ve never seen any stats that show it’s worth engaging unless you are really on the limit, and in those cases reducing speed and drafting behind a lorry will save literally miles more than range mode. Same goes for Chill mode, that makes no appreciable difference in my experience. Just deadens the enjoyment of the car IMO.

The cold weather does have a big impact, as much as 20/25%, so bear that in mind. If the P has 21’’s on that will also impact range.

If the consequence is you need to sit on a Supercharger for a few minutes on the way back, I personally wouldn’t see that as a big deal and certainly not a deal breaker.
 
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Most advice will be that charging to 90% will be fine and running down low every few weeks will also be fine. Truth is we don’t know the 10-20 year effects so don’t worry about it, especially if you have an SC en route. Just take a book or a loo break.
 
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First and most important point: Unless you're both charging to 100% and leaving the car at 100% for extended periods (and the same for <10%), it's highly unlikely that there's much in the way of a measurable effect on degradation. All the evidence so far - gathered from thousands of cars including the Tesloops Taxis that regularly SuperCharge to 100% - is that the battery management system on all Teslas is superb at keeping the condition tip-top. Of course there are outliers, and in particular leaving the car fully charged or discharged is known to affect longevity, but if the car spends most of it's life between 90% and 10%, you can expect "normal" wear and tear to take place. That gets you to the end of the Drivetrain warranty just fine. Rant Over.

Would you consider regular charging to 90% to be much worse for your car than 80%? Would you consider running it down to 10% so regularly to be similarly poor form?

I have a 75D and I regularly charge to 90% for my weekly commutes. Over the winter I also did a weekly just-before-departure top up to 100% (although I normally disconnected at 95-97%) to give me a bigger buffer. I rarely got below 10% even in the depths of winter (...ok it was a mild one) but, crucially, I never once left the car unplugged at that level - Every journey that finished with me <20% SoC finished with me plugging in to keep battery warm and recharge. I have never seen the "blue bars" of unavailable charge on my car. Time will tell I guess but I have no real concerns that I'm "hurting" my battery any more than if I'd left it in the garage at 50-60% maintenance level.

So: Speaking personally, your charge habits are more important than the starting and arriving SoC. You sound like, for your trip, this isn't going to be a problem.

Would you expect a 5% motorway speed reduction to knock say 10% off your power consumption?

Feel free to label me "Grandad" if you like, but I only have 3 data points to offer:

  • Consumption on meaningful trips (>20 miles) with cruise = 75 gets ~3% more consumption on the trip-meter than cruise = 70.
  • However, cross-countries (dual carriageways / A-roads) where cruise <= 60 gives 10-15% less consumption than cruise = 70.
I am frequently passed on the Motorway by Brethren going faster than I (and I am happy to wave them past as I sit comfortably on Autopilot getting through my Podcast backlog) so it's to be hoped there's more data out there. What little I've seen from other online sources is that 80MPH will get you at least a 10% penalty over 70MPH.

I will note that as you guessed above, the single biggest factor is the weather. Right now, late April, temps above 10C and "moderate" winds, I'm back down to the 300-310 Wh/Mile range for my 70 mile commute. In the depths of winter that was above 350 Wh/Mile. In another month or so I'd be expecting to see 280-290, until autumn rolls around again.

What sort of percentage effect would you anticipate from moving from sport to chill and range mode (which I only did for the slower half of my journey)?

None.

Of everything you've listed, only Range mode is expected to have an effect. Ludicrous/Sport/Chill will only be affected by how you use your right foot. In normal commuting traffic it probably won't affect your speed or energy use much at all (... OK, Ludicrous might affect the size of the grin on your face...). Because of regeneration, stomping the loud-pedal every now and again doesn't affect overall range too badly (it's staying at high speeds - more aero losses - that hurts range).

In my experience - somewhat limited I'll admit, but I've used it once or twice on longer trips - Range Mode has little to no effect on the Wh/Mile rates observed; there might be ancillary effects if you're leaving the car unplugged for a while (longer warm-up times -> lower "departure tax" effect?) but it'd be hard to drag that out from the noise.


...this went on longer than I was planning... sorry.
 
As others have said - leaving the battery fully charged or discharged is the issue. Oversimplifying, but under these conditions one or the other electrode gets fully coated with the chemical result from the electrolytic reaction, which bonds with the electrode irreversibly over time. After getting to 100%, if you promptly begin discharging (or charging after getting to <10%) you reverse the electrolytic reaction with minimal long term effect.

Drive at 70mph and minimize heating (AC is not as much of a drain).
 
First, don’t worry about degradation. The car at 500,000km+ that Supercharge multiple times daily certainly haven’t

On colder day when cold, you will get about 30% penalty, but as long as you hav computer set, it will monitor and suggest slowing down.

So I think the question is what are you worrying about?
 
OK. Concensus seems to be that charging high isn't the problem per se, the bad practice is leaving it high (or low). Splitting hairs perhaps, but is it "You can go high(/low), just don't spend long there"? Or, "it's OK to be there but only while the battery's warm"?

Anyway, you lot are killing my excuses not to buy. Every time I bloody come on here! Combination of my test and this extra bit of conservatism I've built in, plus the ease of 15 mins on the supercharger here and there, means this looks like a non-issue for my use case. It does, I think, confirm that my use case benefits strongly from a 100kwh MS over the other EVs out there though.

How does one best manage this? Can I set the normal maximum charge to 80% and then set a time in the week for the car to just hit 95%, say? Can you set a target time to reach full charge in the app? Excuse my ignorance - I don't think I have have app control on a demo car.

Holy grail I guess would be a control system that can act on expected PV generation, for example to mains charge the car to a safe level as soon as its plugged in, then to wait to divert PV power to it up to 90% once the sun shines. Does this kind of integration exist?
 
but is it "You can go high(/low), just don't spend long there"? Or, "it's OK to be there but only while the battery's warm"?

If charging to 100% it’s likely to be warm anyway but it’s the chemical reaction at 100% that can hurt the battery. On the low side it’s the risk of the battery delivering less range than you expected when returning to it - after the battery has cooled. Best practise is to start charging ASAP when arriving at destination at sub 20%. Also the main pack stops topping up the 12v at low SoC, and if the 12v discharges the car shuts down as it’s that that powers the MCU etc.
 
How does one best manage this? Can I set the normal maximum charge to 80% and then set a time in the week for the car to just hit 95%, say? Can you set a target time to reach full charge in the app? Excuse my ignorance - I don't think I have have app control on a demo car.

No, it’s a big failing of the app. You can set the start time and the end SoC required. However third party software eg TeslaFi allow scheduling for all sorts of things. I think @WannabeOwner has a different one for every day of the week ;).


Holy grail I guess would be a control system that can act on expected PV generation, for example to mains charge the car to a safe level as soon as its plugged in, then to wait to divert PV power to it up to 90% once the sun shines. Does this kind of integration exist?

I believe that’s possible but have no experience myself.

Looking forward to the pics of the car in due course :D
 
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Where did you get the loaner from Luke? I want to do the same and try-before-you-buy for a few days to a week. Had a look at a week's rental and it was > £1k

Hi,

I asked the Tesla sales people.

I had a normal test drive then didn't act on it for a couple of months and they chased me up. If an extended test is unusual I guess it's because I had explained my use of a car and it was clear that I wasn't going to buy without confirming to myself that this one would serve my purpose.

I had had a look at hiring too. I did get a quote at a bit over £600 which was I think for most of a week. From a private Co. but they were westcountry.
 
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The "P" is just because that was what was available.

Fraid not ... it was because they expect to UPsell you :cool: I expect you would have been having "fun" in whatever they lent you though, so you probably wouldn't get a realistic figure on the cooking version either ...

I want to do it in the charge range of minimising battery degradation over time

Other posters are of one voice. Forget about battery degradation. You've got a couple of worries that are not real, but of the ones that are: Don't leave the battery charged above 90% sitting there, don't accelerate hard below 10~20%, if arrive below 20% charge immediately-ish. Even then if the car sits for an hour or two in either full/empty state don't sweat it.

car for well over 100k miles, maybe even 200

You need to plan for being able to do your journey in Winter/bad weather and after degradation. You are probably looking at 7% at 100K and 10% at 200K. The only thing we don't know is how much variability there is in high mileage batteries, but the early data from very high mileage taxis, where the owners didn't own the battery, and didn't give a fig, and rapid charged to 100% and left them sitting like that ... has all been very encouraging.

Don't buy / compare again a version one Leaf though :oops:

the new cars are supposedly 10% more efficient

I think it is more than that (and a "definite" rather than "supposed", you'd be able to push a S100D to 400 miles max range at a steady 65MPH if you had to)

There's a supercharger en route half way... coffee may be the worst downside of EV life, is a starting hypothesis I have - I'll have to drink more tea)

Is doing Emails part of your daily job? If so doing them will make the stop time-neutral. New model is going to Supercharge a few percent faster when existing Superchargers are upgraded (that is an in-situ upgrade, not the much more dramatic Supercharger V3 one, might even be software, the announcement made it sound "simple")

There will also be good home/work charging at either end so the battery can start warm

OK ... if you have charging at both ends then nothing to worry about (assuming there are enough hours, at the work end, to get recharged). Assuming 7kW its about 23 MPH charge speed, so if you are there 8 hours that is 160 miles ... not a 100% refuel.

the negatives of battery degradation over time and the effects of cold weather

In perfect weather if I have a journey which is 75% of max range I charge to 100% - detours, foul weather (torrential summer rain is probably worse than UK winter temperatures). Headwind is bad too ...

But if you have Supercharger half way, which you will "Never normally need", I'm not sure I would bother particularly ... you can do Splash-and-Dash if you need to.

Note that journey is quicker if you drive fast [up to 90MPH-ish] and Supercharge longer ... provided that there is a free (unpaired) stall when you get there. IME that is usually "Definitely", except at the 2-stall sites of course.

Would you consider regular charging to 90% to be much worse for your car than 80%?

No. Musk recommends that. My car is set to charge to 90% daily, 100% for trips, and then I change that to 50% (and leave it plugged in) if I am away for weeks on end. I've had it 3 years and done over 80K miles

Would you consider running it down to 10% so regularly to be similarly poor form?

No, except as been mentioned charge immediately on arrival and no hard acceleration.

But I absolutely don't plan a trip if my arrival is predicted as 10%. 10% is 20-25 miles, so enough for most detours and "dozy driver missed a junction", but percentage wise it may not be enough for bad weather. Slowing down in torrential rain doesn't help much (you get the aerodynamic penalty back again, but not the friction/rolling-resistance one). If you have optional charging on that trip then of course its fine, top-up if you need to.

I expect you saw the Energy Graph on your loaner? Put destination into SatNav and then "Trip Energy Graph" shows your consumption from your departure charge %age, to predicted arrival Percentage. As you drive you get an Actual line too, and display of predicted arrival percentage. If that falls dramatically I slow down and as I get closer, if it is above 10%, I speed up.

Draft a juggernaut (at a safe distance) if desperate

Road works and Traffic on UK motorways normally fixes my range :)

Would you expect a 5% motorway speed reduction to knock say 10% off your power consumption?

I think your actual commute is going to be better than your test :) I get on the motorway, select AutoPilot at 75 MPH, and that's it. I give the car a decent follow distance, I let anyone pull in that wants to, if I get some twit up my ar$e who thinks I'm some hopeless octogenarian then when the traffic clears I turn on Warp Drive and show him a clean pair of heels, but that's just for my amusement of course ...

AutoPilot will make a huge difference to how refreshed you feel, on arrival, even compared to cars I previously owned with Adaptive-Cruise-Control. I never take my eyes off the road, always have one hand on the steering wheel ... I would not have believed that just those micro adjustments on the wheel, that I used to do with ACC on motorway, would make a difference, but it definitely does.

Driving consistently like that I have a wide range of actual journey figures and whilst generally worse in Winter / Summer I have good Winter journeys,and bad summer ones.

Worst case is Winter with a cold battery. Pre-conditioning (i.e. plugged into Shore power) helps, but that won't warm the battery. Charging battery for an hour immediately before departure helps, but it will still be cold (iPace does a better job in that regard). If you make multiple stops, in Winter, "travelling salesman" your range will be dreadful because each time you stop battery will get cold again, and you will have the "cold battery start penalty".

Once warmed up, trogging along the motorway at 75 MPH is OK.

On the days you are in range just drive. On max-range-challenged days then plan ahead, and use Energy Graph and slow down / speed up according to predicted arrival %age

Just looking at my logs for my range-challenged journeys

One day in February, 520 miles driven:

Leg-1, 8C, 174 miles, 373 Wh/mi Motorway Avg 55MPH
Leg-2, 10C, 64 miles, 371 Wh/mi Motorway Avg 63MPH
Leg-3, in range of supercharger, empty A-road across Wales, having fun :) 10C, 92 miles, 459 Wh/mile :eek: Average 43 MPH
Leg-4, 11C, 160 miles, 380 Wh/mi Motorway Avg 55MPH

Looking at a couple of other Winter journeys 370 Wh/mile seems to be my "range challenged journey motorway-cruise leg" consumption

sport to chill

Makes no difference to range (other than stopping you "flooring it" :) ), and Chill does NOT have kick-down, so I never use it.

range mode

I always use that on long journeys. Habit. Definitely will only make a (tangible) difference on dual-motor models, probably not enough to worry about

The cold weather does have a big impact, as much as 20/25%

I don't reckon it is as much as that, on a longer Motorway leg.

Truth is we don’t know the 10-20 year effects

I reckon anyone planning 100K ownership is either high mileage, and will get to 100K in 3-4 years, in which case the existing Taxi data is comparable, or will be majority short-journey driver, in which case some loss of range may not matter too much.

My suggestion would be NOT planning to keep it that long. This is really new technology, there will be a point in the future where you may well think "this car WILL last for 1,000,000 miles" and maybe plan to buy a forever car at that point?

Try your journey(s) in A Better Route Planner. You can choose current P-Turbo-Nutter model that you had as a loaner, and see driving time, charging time, and consumption, and then re-try it with one of the Beta "new long range 2019 models" and see how ABRP rates them. ABRP is well liked, its data seems to be accurate - notwithstanding no actual real-world data for models not yet launched. You could try the journey in the 2020-Roadster too ... if you like :)

If you are buying new get a referral code off someone to get you (and them) some free Supercharging. If you use mine and I win a Roadster in the draw you can borrow it ... trouble is, I won't know which referral got the Roadster and I will be lending it to so many hundreds of people I won't get to drive it myself :rolleyes:

I think @WannabeOwner has a different one for every day of the week

if I didn't know you better I would think you were taking the Mickey. I (truthfully) have 20 items in my TeslaFi schedule :)

a control system that can act on expected PV generation

Zapi Wall Charger will divert excess PV to car (rather than export it) ... but you have to be parked at home during the day of course
 
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OK. Concensus seems to be that charging high isn't the problem per se, the bad practice is leaving it high (or low). Splitting hairs perhaps, but is it "You can go high(/low), just don't spend long there"? Or, "it's OK to be there but only while the battery's warm"?

Two slightly different cases, as I understand it, but your first statement is closest to correct. In English as plain as I can manage (...given my struggles, not yours):

  • Try not to let the car sit for long periods when the State of Charge is over ~90%. You get to define what a "long period" is, but ideally you'd drive the car away as soon as you hit 100%. BUT: don't stress about this. This is a cumulative effect over long periods - leaving it full every once in a while for a few hours isn't going to cause noticeable degredation.
  • Try not to let the car sit for long periods when the SoC is below 10%, with the inverse rules to the above. Additionally, if the weather is cold, charge as soon as you can after a drive where the SoC drops below ~20% (this is more to prevent additional cold-weather range loss than battery damage).
  • If you are leaving the car with no intent to use it for long periods, set the charge level to 50-60% to maximise longevity.
  • Do not let any of the above stop you from enjoying the car, from using it's potential, and for undertaking the odd 100-0 long trip just because you can.
 
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ideally you'd drive the car away as soon as you hit 100%

One thing to add in is that it takes a good hour to charge from 90% to 100% - even at a Supercharger it slows RIGHT down charging at that level to not damage the battery. So the battery has already been above 90% for a hour due to the charging ...

I just think that if it was a problem Tesla would not have built it like that - iPace only charges to 100%, there is no option to charge to lower MAX limit. They have reserved some top-end to prevent battery high-charge damage ... and consequently iPace has 10% less range and no option to brim-fill the tank. I prefer the Tesla option of giving me the choice, I am just thoughtful about when i use it.

Other point is that on the occasions you do charge to 100% the charging then balances the cells, so it is a good idea to do it now and then, for that reason alone. Dunno how often is right, perhaps once-a-quarter is enough for that purpose ...
 
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Would you expect a 5% motorway speed reduction to knock say 10% off your power consumption?

That depends on what the starting number is that you are knocking 5% off! 90 down to 85 will have a bigger effect than 70 down to 65, but even the latter is still noticeable.

I would certainly expect to knock at least 10% off between "having fun" and normal driving.

You don't say what the trip length was or what consumption you were achieving. My car's lifetime consumption is 336Wh/mile, going up to about 350Wh/mile in winter and correspondingly lower in summer. This is with mostly long journeys, and typically driving motorways with a target speed of 75.

My car is an S85; a current 100D ought to do better with the two motors, and the new 'LR' (100D with better motors) should do better still. Your test P100D will lose from both being a 'P' and from (presumably) having the 21" wheels with stickier tyres on them.

What sort of percentage effect would you anticipate from moving from sport to chill and range mode (which I only did for the slower half of my journey)?

Chill mode won't have any effect that you couldn't otherwise have achieved by moderating your right foot. Range mode will have most effect on a P100D as that has the small front/big rear motors and so gets maximum benefit from switching power delivery to the front motor which is what Range mode does on 'D' cars. I can't give you a number as my car is RWD and so range mode only affects the HVAC and doesn't have a great deal of effect.

Overall I think I'm in a decent place here, but I'd like a buffer and to treat this expensive battery with care.

As others have said, I think you are being over-cautious of the battery. Charging regularly to 90% doesn't seem to be a problem. You do want a decent amount of margin for winter use, but your benchmark of a long non-stop journey is relatively less affected by cold weather (the worst is lots of short hops, parked at each stop long enough for the car to cool down - that can give you terrible Wh/mile numbers, but you can't do enough miles in a day with that sort of pattern for it to actually matter).
 
My car's lifetime consumption is 336Wh/mile, going up to about 350Wh/mile in winter and correspondingly lower in summer.

Sorry @arg, but I don't think lifetime or specific-whole-month (Winter/Summer) averages are helpful. I think that the only thing that matters is days which have range-challenged journeys, because all other journeys will include "cold battery start, averaged over short-ish journey", and also all the "Short journey, I'll pretend I stole it" ones :)

The range-challenged journeys are going to be the ones that do not have Superchargers placed such that there is multi-choice of where to stop ...

Leaving home each morning with 200 mile range means that if your day is less than 150 miles you can Hound It if you like.

I was at M25/A1 roundabout the other day (its a biggie, with lights). Crawling round, stopping for Red each time :(, I passed a very throaty Jag in the other lane ... he slipped in behind me and I wound up first on Red at the last light before ramp onto A1 ... I thought he might need a demo of why he should ditch Petrol for Electricity and was gone into the distance before he had even got his pistons up to full chat ... momentarily forgot about Range :)
 
Thanks for all the help. This is an education.

I haven't reset my trips unfortunately but I can see mid to high 300s over my time with the car so far. And that's gently driven for some short journeys but my long one was less efficiently driven than normal. And I've had a few goes at ludicrous plus (why is there a middle setting of ludicrous without the plus?), obviously!

I'm relaxed about this now. My long journey is 190 miles with charging at either end. When I get to work it can charge over 3 days and 2 nights, on and off, so a 7kw charger would be fine. And my energy use chart has sat pretty close to the "budget" line. Bad weather and I can supercharge. Right now when I put the journey in, the car currently at 77% only has a 15 min email stop planned.

There's also a supercharger 5 mins from work as backup.

Looking forward to the pics of the car in due course :D

So to the big question...

What colour? And are white seats idiotic for someone who is, frankly, going to get mud everywhere every now and then? Current fave option is blue with white seats.
 
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Echoing the above, there is a lot of evidence that Tesla's are excellent at preserving battery capacity so it shouldn't be an issue. If the Nav thinks you're short on range, it tells you to slow down for the simple reason that this dramatically reduces energy consumption. If you can bear to drive at 65, or 60, or dare I suggest 55 mph if circumstances dictate then range won't be an issue, even in the depths of winter (and really that's the case to consider - do you have a plan that works on a wet, windy, winter day: if so then all other cases will be covered).

One issue that is starting to get mentioned more now (as batteries get older) is that the maximum Supercharge charge rate is beginning to be limited on some older batteries. Apparently the rate is tapered based on number of kWh of DC charging, reducing the max rate to 80-90 kW (from the current max of 120 kW). Happily, since the OP will most likely be destination charging on AC, with Supercharging as a backup, this shouldn't be an issue. In any case we don't know how the newest battery packs will behave (most discussion I've seen relates to the 90 and 75 MS/X).
 
why is there a middle setting of ludicrous without the plus?

I haven't got that update yet, but what is now PLUS was previously a separate MAX setting. That forced max optimal battery warming (which could take half an hour ...) and you had to have a reason to want to use it. Then you had to do the whole Launch Procedure . foot on brake, press accelerator all the way to the floor, release, foot back on accelerator again, and only then release the brake when you are ready. I've done it maybe once or twice, way too much palaver ... at the traffic lights just stamp on the Loud (Ahem!) pedal and off you go :)

Once upon a time there was a limit to the number of such launches you could do (in lifetime of the car, same with Evo and other "launch mode" equipped cars). Tesla removed that restriction ... and maybe now has found that there are no Warranty / wear-and-tear issues that they are comfortable to allow its use "all the time"

And are white seats idiotic

Bjørn Nyland has a YouTube on it ... he had a lot of trouble with the white seats picking up the blue dye from his Jeans.