SageBrush
REJECT Fascism
I don't think the calculation works that way. The inverter is a minor contributor to the overall car efficiency.
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Mid range battery available now?
- Thread starter TurnFast
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- Model 3 Tesla Inc.
omgwtfbyobbq
Active Member
It can, but it depends on the drive cycle. Apparently 1-5% is common on different drive cycles.
https://www.infineon.com/dgdl/IISB_SiC_Studie_Part2_v2.pdf?fileId=5546d461580172fe0158249537a00222
And the difference is greatest at low loads.
https://www.edn.com/Pdf/ViewPdf?contentItemId=4442541
The other thing that could account for the difference is if Tesla sets aside a static amount of battery capacity to avoid bricking the pack. With a smaller pack, that would be a larger amount of the total capacity. In that case the inverter could be a 3-4% difference and the reserve capacity could be a 1-2% difference.
Not sure if this has been asked before, but based on what we know so far and info that has been revealed by the parts catalog, would it be possible to add battery packs to the mid range later on as a mod and effectively make it a long range?
voip-ninja
Give me some sugar baby
Lol no. If you want long range order it off menu while it is still available.
Theoretically it will eventually be possible to retrofit a larger battery but it most certainly won’t be cost effective compared to just buying the larger battery in the first place.
ℬête Noire
Active Member
The pack is externally the same, outside of being lighter, so it'd be relatively easy to swap it physically and any cables with it should be fine as they'll be larger (they don't even need to be larger, except the AC line running from the charge port). However it'd need at least some customization of software by Tesla to account for the hardware difference of a battery with more current available hooked up to what appear to be drive units designed for utilizing less and software that things the pack has far less charge room than it does now. It's not impossible but seems extremely unlikely Tesla would offer it as an official option given the price-point to start with. "Just trade your MR in to buy a new LR."
The MR is going to have a very useful range for a long time to come, someone is going to get use out of that used vehicle with the original gear in it.
I think most of the 80%ers are driving faster than 65 mph. A lot of people think they'll get the full range driving 75 - 85 mph which is total fantasy. The range falls off rapidly over 65 and increases rapidly under. In fact, a standard LR going 55 mph can go well over 400 miles on a full charge according to the charts I've seen. I can vouch for the huge difference speed makes because I drove a 2011 Leaf for six years and there were many times when I had to milk it for every mile I could get. At 50 to 55 mph I could still make 60+ mile trips even after losing 2 capacity bars.
ℬête Noire
Active Member
Keep in mind that the Leaf has somewhat more drag. According this site, once you convert from ft^2 to m^2, the CdA of the Leaf is 0.644.
Best number I've found for the Model 3 are (0.23 Cd * 2.36 m^2 frontal area) = 0.543. EDIT: Oops, bad old number that was Tesla's original target. Fixed.
The result in the Model 3's fall-off, due to drag being CdA * speed squared, doesn't hurt quite as much on the Model 3 as it does on the Leaf. This is why it's pretty common for people to feel comfortable driving their Model 3 at 70mph. On the RWD LR w/18" Aeros you're still able to get over official listed nominal range because of the sandbagging Tesla did couple with that crazy low Cd and having a small front profile.
Of course if you throw on the A/C then all bets are off, depending on temps/sunlight involved, but still before that it's pretty amazing how far you can get at Interstate speeds.
EDIT: Added the link I'd forgotten.
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The chart I'm using shows the rated range is at 60 mph, while at 70 mph the range drops to 250, at 80 it drops to 225, at 90 it's 160. My friend in Austin where the highway speed limit is 85 mph and she can "get away" with 100 mph frequently uses 80 miles of charge to go 40 miles. I've read that the "real" is more than the chart shows, so I guess it depends on who you believe. Some people claim 330 is the "real" range while others say they get 310 just like the sticker. It's a little confusing to be honest.
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ℬête Noire
Active Member
I don't know the source of that chart or it's assumptions but I get better than that in my AWD....at 75mph. ((w/otherwise very good conditions))
Also it's peak is definitely off, >600mi is possible at roughly 25mph.
Unfortunately, I can't remember where I got that chart. I thought it was from a "real world" driver. I'd like to go back and see if there is info about how they derived the numbers. Do you have a chart from real world drivers?
This guy's chart claims much greater ranges:
Tesla Model S/X/3 range at 55/60/65/70/75/80 mph
This guy's chart claims much greater ranges:
Tesla Model S/X/3 range at 55/60/65/70/75/80 mph
ℬête Noire
Active Member
250 mile range implies 75kWh/250mile = 300wH/mile. I've never seen such things as that chart implies when traveling for meaningful distances. Maybe they had HVAC roaring on 19" wheels? ¯\_(ツ)_/¯ That might be about right, then.
Traveling at 70mph-75mph, variance because of traffic, w/'modest' Texas AC (enough the wife doesn't get angry
) gets me around 280mi. If you then knocked off 10% for 19" optional wheels then you'd be around 250mi.EDIT: Something else that person may instead be doing to call it "real world" is only using a certain fraction of the battery. Say never taking it below 15% SOC, or something.
Yes, and that's a lot more inline with what I see.
((Keep in mind though that Troy is mixing on that table solid measured, actual data and also backfilling w/calculations, which isn't easily apparent just looking at the table. This can lead to 'surprises' if you don't look further to understand which is which and how he works out the numbers. For example I expect he's far too optimistic on his MR projections. I saw how he got there, he's good in that lays out his work, and take issue with aspects of the methods he used.))
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very true. Tesla has mastered the first principles, while other EV makers seems to struggle on these ones.
which is why I don't understand Tesla does not offer the Model 3 Performance AWD with 18 inch aeros any more for now. Nor the LR RWD.
They've effectivly stripped 2 high range variants of existence, in 1 week.
Could be that they need those aeros for MR builds, and their supply of aero wheels is limited? Perhaps with the popularity of the aeros (being 2 for 1 wheels as you can take off the aero covers for looks or keep them on for range) was enough that they now have an excess of 19's ?
SageBrush
REJECT Fascism
I'll take your word for it and say the inverter losses are 2.5% of the total. I find it easiest to the think of the inverter as then having a 1/40x effect on the total car efficiency. A 5% drop in inverter efficiency would affect the total by 5/40 = 0.125% and the range would drop by R/100.125
aka, a rounding error
Very interesting discussion on batteries. Thanks guys!
One question, does "stop-and-go" city traffic affect range in the same way it does in ICE cars?
I see from the chart that driving 25mph nonstop would produce the best range, but does accelerating the car to city speeds of 25-45 make the car less efficient than maintaining 65 on the highway?
One question, does "stop-and-go" city traffic affect range in the same way it does in ICE cars?
I see from the chart that driving 25mph nonstop would produce the best range, but does accelerating the car to city speeds of 25-45 make the car less efficient than maintaining 65 on the highway?
Model 3 Performance with Performance upgrade package requires wheels bigger than 18 inch as far as I know, aka they wont fit.
I misread the post I replied to as saying you can't get 18's on any AWD models, though Performance was clearly stated (I just missed it). Thought they'd made yet another change. Oops.
Yeah, obviously for Performance with + package included now you can never ship a Performance with 18's
Yep, and that's why I was particularly upset: According to Troy's list, theres is no range penalty Model 3 LR AWD vs. Model 3 LR Performance AWD when equipped with 18 inch aeros.
ord3r
Member
That performance base with Aeros and 5k rebate is looking like the unicorn configuration, would have definitely ordered that if I knew Fred was going to complain so much and get us that deal
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