-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Calvin.K
Member
A challenge for people interpreting these numbers is that they are probably only true when starting from a nearly empty battery (which we are supposed to avoid!) - and the mileage/chart likely looks different for 60s vs. 85s..
Because it takes so long to go from 80% to 90% and then much longer from 90% to 100%, what might be more easily understood would be to provide a chart showing the amount of time to reach 80 or 90% charge, based on how depleted the battery is - this would be the time required to stop for "refueling", comparable to a stop with an ICE at a gas station. If you don't need more than 80 or 90% to reach the next charging station - then it doesn't make sense to spend the increasing amount of time to "top off".
Because it takes so long to go from 80% to 90% and then much longer from 90% to 100%, what might be more easily understood would be to provide a chart showing the amount of time to reach 80 or 90% charge, based on how depleted the battery is - this would be the time required to stop for "refueling", comparable to a stop with an ICE at a gas station. If you don't need more than 80 or 90% to reach the next charging station - then it doesn't make sense to spend the increasing amount of time to "top off".
Depending upon what the next charging station is. If it's a Supercharger, then yes. If it's a slow charger, then spending the extra time saves a bunch of time at the slower charging point.
lolachampcar
Well-Known Member
Cottonwood
Roadster#433, Model S#S37
I do this often when I leave Silverthorne headed south to Pagosa Spring, CO with a 70 Amp J1772 in Salida. In an 85 because of the higher DC Voltage vs AC Voltage (400V vs 240V), and the increased charging efficiency at DC, the ratio of currents for the same charging rate in MPH is about 2:1, J1772 to SC. To minimize total charging time, it is best to charge on the Supercharger as long as its charging rate is greater than the charging rate of the next charger (assuming you can make it there). For me leaving Silverthorne, that threshold is 35 Amps at the Supercharger; 1/2 of 70 Amps). At that charging current, the MS is at over 95% State of Charge, but boy is it nice not waiting for that last 5%; it takes forever...
Cottonwood
Roadster#433, Model S#S37
I respectfully disagree.
I believe that Tesla corrected the first 30 minutes of charge starting at zero on a new 85 to include the little bit of taper that happens, even at 50% state of charge, rather than just blindly multiplying 400 mph charge rate by 1/2 hour, both using rated miles.
That is very possible. However, the page clearly says EPA rated range on the side of the graph now.
Cottonwood
Roadster#433, Model S#S37
Yes, but I think that it was alway "EPA rated range." What they need to further state is that this chart is starting from zero for a new 85 kWh MS.
All of the Supercharger kW to mph conversions have seemed to have used 300 Wh/mi. That is remarkably consistent with some battery charging loss (3%) and the displayed, rated miles using a conversion of 290 Wh/mi. If you use the 300 Wh/mi conversion, then 120 kW converts to 400 mph. A 1/2 hour at 400 mph charge sure seems like 200 miles in a half hour to a marketing person under pressure from the boss to get a slick Supercharger page on-line. The only problem is that the taper starts even below 50% SoC and you don't quite get 200 miles in 30 minutes. The earlier page was not consistent with the charge curve lower down on the page. 80% of 265 miles is 212 miles in 40 minutes. To go from 200 miles in 30 minutes to 212 miles in 40 minutes would mean the charge rate slowing to 12 miles in 10 minutes or 72 mph. 170 miles in 30 minutes then 212 in 40 minutes means 42 miles in 10 minutes or slowing to 252 mph for that last 10 minutes, which is much more consistent.
This discussion illustrates the challenge Tesla marketing has to deal with: how to convey an accurate but sufficiently simple message to the average consumer. Most people don't want to be overwhelmed with unfamiliar concepts like how the charging rate varies over time depending on the initial state of the pack and how high you want to charge to depending on the distance to your destination. They just want to know "How fast does it charge?" Of course the answer to that question is "It depends". However, given that BEVs are new and exotic to most people, an answer like "You can charge at X mph" is an acceptable initial response.
Agree. A simple miles per hour explanation seems simplest. I think it's been misleading for Tesla to claim that you can replenish half your battery pack in 20 minutes, 200 miles in 30 minutes, and 80% charge in 40 minutes. The reality is, in order to pickup enough miles to make it to the next supercharger, plan to spend about an hour.
The supercharger bar is still 200 miles high. The 30 and 40 Amp AC charging bars are scaled correctly.
Tesla needs to fix the scaling. The whole concept of bar graphs is to visually compare magnitudes, and this only works when the scaling is correct. The current bar graph is misleading.
GSP
Tesla needs to fix the scaling. The whole concept of bar graphs is to visually compare magnitudes, and this only works when the scaling is correct. The current bar graph is misleading.
GSP
Cottonwood
Roadster#433, Model S#S37
6 or 7 miles of rated range near zero is about a minute. Going from 7 to 200 in 35 minutes to 200 in 35 minutes is the same as 0 to 200 in 36 minutes. 170 to 200 in 6 minutes is a 300 mph charge rate. 200 to 212 in 4 minutes is a 180 mph charge rate.
Within the margin of error (mostly time +/- a minute), these are all consistent numbers. Amazing!!! :wink:
gg_got_a_tesla
Model S: VIN 65513, Model 3: VIN 1913
The graphic on the wall inside the Hawthorne design studio lobby near the Supercharger there hasn't been changed yet. Particularly ironic given how below-average the charging rates and for that matter, the total time spent there (including waiting for stalls to open up) can get...
Wow! That's insanely fast. I'd be so happy if my car could charge that fast. Unfortunately, Tesla sold me Supercharging-Lite.
gmontem
Model S P01707
So I see a graph for 170 miles of some unit for 30 minutes for 120 kw Supercharging. Why don't they also include a graph for 90 kw Supercharging, seeing they have no interest in making that available to the early adopters, who without their $5,000 and $40,000 interest-free reservations would have made it difficult for Tesla Motors to become what they are today?
Similar threads
- Question
