strider
Active Member
Could this just be a rated/ideal difference? Maybe the 31mph number is ideal and Francis is set to rated? Rated miles take more energy than ideal miles. I have mine set to Ideal and will check it's charge rate tonight.
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I thought we get 31 miles per hour with NEMA14-50
- Thread starter Francis Lau
- Start date
No, I'm set to rated. It's a "feature" in the way the car is showing miles per hour of charge. The car does get 31 rated miles per hour, but the display only shows 21ish for the first half hour or so.
This seems contrary to previous info. If this were true, the twin chargers would be a 'must-have'.
Agree. If this is the case, then the whole charge calculator on the Tesla site is completely misleading. I would seriously doubt this is the case. (And I can't think of a real reason why it would be the case). I don't doubt that what you were told, but it just doesn't make sense to me nor does it jive with the very nicely designed charge calculator featured by Tesla themselves.
Adapter Guide on the same page shows 5 mi/hr on 110V/12A but I'd bet money against that. Most I ever saw was 3.
Okay, just for reference my car currently shows 20 mi/hr charging rate, but my rated range is 200 miles and it says 1 hour 23 minutes remaining. 31 * (83/60) is 42.88 miles, which would put me at ~240 mi.
So, the "mi/hr" indicator is wrong on the car. It is getting 31 mi/hr of charge.
So, the "mi/hr" indicator is wrong on the car. It is getting 31 mi/hr of charge.
Correct, but Francis has 235v per his picture, which would be just over 30 mi/hr of charge for him. The point of the post is that the indicator on the dashboard as to how many mi/hr of charge you're seeing is incorrect. Mine still shows 20 mi/hr @ 243V 40/40A, but 1 hr 10 min remaining with 207 mi of range.
And everyone's double checked that they're not set to projected because that can make the numbers look odd? If that's the case, the next thing to do is check the actual line voltage. If the line voltage isn't 240, then the the display is only showing the type of plug and extracting the voltage from that. The older software appears to show the real incoming voltage but perhaps a bug was introduced in the new software.
It's showing the real voltage, real amps, real number of miles added to range, and real projected time to completion. The only number that is incorrect is the displayed miles/hour. Mine shows 20 when everything else lines up -- and that's because for some reason my setting was put back to "rated" vs. "ideal". It shows 32 when you double-check.
dhrivnak
Active Member
I do not see how one would get 31 miles per hour. At 240volts and 40 amps that is 9600 watts. W e lose about 10% in charging losses so we are down to 8640 watts. If you use 350 watts per mile that is about wt miles an hour. Maybe in the smaller Roadster but not in the Model S.
I'm not seeing losses anywhere near 10%. I'm seeing maybe 3-4% at worst.
The 'rated' numbers are based on 300 Wh/mi. 240*40/300 = 32 mi. Tesla uses 31, that's about right.
OK, here is possible a bit more information. I drove it down to about 150 miles range remaining today. Then, I started charging. A few hours later, I checked. This is what I see. I am parked outside and it was about 44F so I wonder if temperature has anything to do with it. Have others who have their cars in their garage see different rates?
By the way, thanks to everyone for helping to figure this out.
By the way, thanks to everyone for helping to figure this out.
Francis, go into the car's settings and change your mileage from "rated" to "ideal" and it will show it properly. There seems to be a bug in how it's calculated when you use "rated" mode.
I think when it shows 40 / 40A it's giving all the juice to the battery; I suspect it would show less if some power is being diverted to heat etc. I've been charging 100% outdoors and I've always seen 68 / 69A (don't know why it says 69A because I've always charged from 70A sources).
My understanding is that folks above have concluded that with 4.0 (and beyond) (a) you have to have the setting set to Ideal range for it to show 31 mph charging for 240V/40A and (b) people are calling it a bug that a lower number is reported for the Rated range setting.
What I'm having difficulty understanding is (b). Why do people consider this a bug?
What I'm having difficulty understanding is (b). Why do people consider this a bug?
I went out and change my settings from "rated" to "ideal". I will see if it shows 31 miles/hour tomorrow when I charge.
Tonight my projected is closer to rated. And tonight I'm showing 26 MPH of charge. Other nights (same plug, voltage, and amperage) I see 20. If I set it to ideal, it shows 32 MPH.
Now, remember that pre-4.0 the switch was projected/rated and now it's rated/ideal. Pre-4.0, setting to projected would show 26 -- makes sense. Setting to rated would show 32 -- makes sense. It sounds like with the 4.0 update, they forgot to update the MPH calculation to reflect rated/ideal instead of projected/rated with that switch.
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I always see it waiver between the set amperage and 1A less. And turning the heat on doesn't change the amperage display -- but it DOES change the ETA for "charge complete" ...
Now, remember that pre-4.0 the switch was projected/rated and now it's rated/ideal. Pre-4.0, setting to projected would show 26 -- makes sense. Setting to rated would show 32 -- makes sense. It sounds like with the 4.0 update, they forgot to update the MPH calculation to reflect rated/ideal instead of projected/rated with that switch.
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I always see it waiver between the set amperage and 1A less. And turning the heat on doesn't change the amperage display -- but it DOES change the ETA for "charge complete" ...
Because at 300 Wh/mi ("rated" consumption avg), 40A delivers far more than 20 mi/hr of charge.
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