Dec 21, 2012
Francis Lau For the first time, I paid attention to the charging info after I plugged in my car. I noticed that I am charging at only 14 miles per hour as shown below:
With my NEMA 14-50, I thought I should be charging at 31 miles per hour. Below is what the Tesla website says:
Is there something wrong with my setup? Or am I misunderstanding something? What are other Model S owners seeing?�
Dec 21, 2012
ChadS Yeah, you should get more than that. The display says you are at 236V and 40A, so it's not like you have greatly sagging voltage, or lowered current because your connector is not fully inserted.
My best guess (?) would be that you recently plugged in, and it diverted power to cooling the battery or something like that first. The number should rise after a while.�
Dec 21, 2012
brianman Do you have pre-4.0 software and your speedometer range set to Projected?�
Dec 21, 2012
Francis Lau I have version 4.0 and I believe that with this version, I cannot set the speedometer range to projected. It is always rated, I think.
Does this affect charge rates?
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My car is not charging at this time, I am going out to plug it in and then sneak out 30 minutes later to see what the charge rate is.�
Dec 21, 2012
Jason S The +0 miles charged indicates this is right after you plugged it in. Give it a few miles of charge (5m or so) and the rate becomes pretty accurate and consistent.�
Dec 21, 2012
brianman In pre-4.0, the Projected vs. Rated display setting impacted the reported charging rate (in miles) in the UI. AFAIK, it didn't affect the actual rate of charging.
In 4.0, I presume(d) that the Rated vs. Ideal has a similar impact but given that both Rated and Ideal are fixed numbers there isn't the same sensitivity to driver history that Projected had.�
Dec 22, 2012
Francis Lau Here is about 15-20 minutes after charging
Still not close to 31 miles per hour, just 20. Are you seeing closer to 31 miles per hour? What rate exactly are you seeing?�
Dec 22, 2012
AltPowr Francis, I was wondering the same thing - I usually only see about 20-21 mi/hr when I charge at home with my 14-50 outlet. I also see about 39-40 amps on the right side of the display - pretty much exactly what your picture shows above. I have never see anything above 21, not even close to the 31 defined by Tesla. I was wondering if the HPWC will make a difference when it arrives?�
Dec 22, 2012
elecblue Francis -
First of all, congrats on software V 4.0. I'm still waiting for mine. I can tell you have yours since the picture you posted is not a red Signature Model S.
Secondly, the last picture that you posted shows the car at 238 miles. In my Standard charging mode (and I haven't made any adjustments to this - not sure if you are able to do so), that's about the limit that I charge to. Therefore, the car is getting close to it's max range in Standard mode and will automatically back down the charge rate (but that isn't indicated on the current draw).
You may want to take a picture and post it after about 20 mins. of charging but way before you hit 238 miles on the charge meter. If it is still only showing 20mph, then perhaps a screen reset will solve this (not sure, but just reaching for a possible solution).�
Dec 22, 2012
Yggdrasill Is it correct that you are at 90% SOC?
The charging slows down as you approach a full charge. It doesn't matter if you are plugged into a NEMA 14-50 or a supercharger, the battery will limit the charging.�
Dec 22, 2012
Futurist Do you have a single or dual chargers in your car? I was told by a Tesla engineer that the cars with only one charger charge a lot slower than those with dual chargers. I got up to 29/miles with 40A at 203V on a NEMA 14-50 (but only after a while of charging). Have dual chargers.�
Dec 22, 2012
cinergi I believe 4.0 has a bug where it's showing projected MPH for charge (even though you can't select project as an option anymore). I'm observing the same inaccurate number -- but it will vary quite a bit between sessions even with the same voltage and amperage -- and I believe that's because it's using projected range. I also did some math and it seems to line up wth that theory. I already let ownership know. I'm not sure if it's fixed in 4.1 (I haven't tested yet).
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Not true for a standard mode charge at 240/40 in the Model S.�
Dec 22, 2012
yobigd20 Single charger is 31mi/hr on 240volt. Dual charger is 62mi/hr but requires HPWC. Says so right on their page. http://www.teslamotors.com/charging#/highpower�
Dec 22, 2012
Zextraterrestrial I get 32 mi/hr at 40 A 243 volt
less if voltage is only 220 or so (Hopland)
edit: this was v .39 in rated�
Dec 22, 2012
cinergi Software version and range setting (projected/rated/ideal)?�
Dec 22, 2012
FlasherZ I've found the display of miles per hour of charging is averaged over a long, long period of time. Right now my car shows 183 miles rated range, 1 hr 56 minutes remaining to charge, 245V @ 40A, although it shows 21 mi/hr charge rate. I've found the "remaining to charge" to be calculated correctly.
Your voltage is slightly lower, so your miles per hour will be lower, but only by 1 mph or so.�
Dec 22, 2012
RDoc FlasherZ sounds right to me. In the first example there's about 125 miles of charge to go with a 3.75 hour estimated time remaining. That's about 33 mph.�
Dec 22, 2012
Futurist I was told that cars with only one charger take quite longer for all charges compared to those with dual chargers. The mechanics in the Tesla Center in Queens told me, that at their NEMA 14-50 outlets, the singe charger cars take almost 40% longer to charge than those with dual chargers (at the same outlet). It has to do with the fact that in the master-slave-configuration of the dual chargers, they even charge quicker if only 5 or 8 KW are provided.�
Dec 22, 2012
montgom626
Do you have the time to post a picture of the screen when you are charging at that rate?? Thanks!�
Dec 22, 2012
goaliemanshark Try depleting your battery to low, plug in the car, wait 20 minutes and then check.�
Dec 22, 2012
strider 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.�
Dec 22, 2012
FlasherZ 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.�
Dec 22, 2012
joshuaeven
This seems contrary to previous info. If this were true, the twin chargers would be a 'must-have'.�
Dec 22, 2012
jomo25 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.�
Dec 22, 2012
brianman 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.�
Dec 22, 2012
FlasherZ 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.�
Dec 22, 2012
jerry33 It depends on the acutal incoming power. A real 240V at 40 amps will get 31 mph, 220V or 208V won't. Same with 120V, 110V or 108V won't. Cinergi has a video here.�
Dec 22, 2012
FlasherZ 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.�
Dec 22, 2012
jerry33 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.�
Dec 22, 2012
FlasherZ 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.
�
Dec 22, 2012
dhrivnak 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.�
Dec 22, 2012
FlasherZ 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.�
Dec 22, 2012
Francis Lau 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.
�
Dec 22, 2012
FlasherZ 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.�
Dec 22, 2012
aviators99 Mine shows rated and it usually goes between 29-30 mi/hr. My volts are usually between 239-244, with Amps switching between 39 and 40.�
Dec 22, 2012
Doug_G 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).�
Dec 22, 2012
brianman 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?�
Dec 22, 2012
Francis Lau I went out and change my settings from "rated" to "ideal". I will see if it shows 31 miles/hour tomorrow when I charge.�
Dec 22, 2012
cinergi 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" ...�
Dec 22, 2012
FlasherZ Because at 300 Wh/mi ("rated" consumption avg), 40A delivers far more than 20 mi/hr of charge.�
Dec 22, 2012
cinergi Rated should show 32 MPH (what it's showing varies based on *projected*) and Ideal should show 37 MPH.�
Dec 22, 2012
brianman I find this confusing. Why wouldn't Tesla have been advertising 37mph charging back before we had EPA numbers? I thought they had been saying 31/62 for a long while before we had EPA numbers.�
Dec 22, 2012
cinergi Excellent question. I don't have a good answer.�
Dec 22, 2012
brianman My math doesn't match yours. Let's see if we can bridge that:
Ideal: 85 kWh / 300 mi. = 283.33 Wh/mi.
Rated: 85 kWh / 265 mi. = 320.75 Wh/mi.
Where am I going wrong?�
Dec 22, 2012
cinergi It appears we don't have full access to the 85 kWh. The 300 number (I think it's slightly above -- I've been using 308) comes from two places: 1) Seeing the average WHPM in the car when rated matches projected and (with version 4.0) the location of the "rated" line in the graph.
So when I "reverse engineer" the pack capacity, I do 265 * 308 = 81620 ... and then to get the whpm required for 300 miles, 81620 / 300 = 272 whpm.�
Dec 22, 2012
brianman Tesla Charging | Tesla Motors
Input: 300 MILES, (whatever), NEMA 14-50 (240V/80A), (whatever)
Output: TIME 09:26, (whatever), ENERGY 84.9 kWh
300 mi. / 9.433 hr = 31.8 mph
Where does the 37 mph figure come from?�
Dec 22, 2012
cinergi Using what I posted as you were writing this, 10000 / 272.
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I wouldn't be surprised if their calculator is including charging overhead. Their 84.9 is 4% higher than my 81.6 ...
As for their time estimator -- yeah it's the 32 number, which is definitely strange. I don't really trust their site. At this point, what I'm posting is based from owning the car for 2 months and measuring these details.
*shrug*�
Dec 22, 2012
brianman Another point that confuses me is that the raw numbers show the Charging page to be overpromising as well. Check me on this one as well please.
Model S Specs | Tesla Motors
From wall: 240V * 40A = 9600 W
Efficiency: 92% (best case)
To battery: 9600 W * 92% = 8,832 W
Assuming linear charging (which we know to be overly optimistic):
85,000 Wh / 8,832 W = 9.624 hr
So assuming we stay at peak efficiency for the entire duration of the charge and overly optimistically assume linear charging, we get 9.624 hr which is still longer than the "calculated" 9.433 hr.
#confused
Every way I try to slice it, the numbers end up worse than suggested by Tesla. Sad panda.
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Getting back to my original question about (b). I got the impression that people were saying that it's a bug that the Rated/Ideal setting impacts the reported "mph" of charging. I consider that an intentional feature (to be kept) rather than a bug (to be fixed).
If, OTOH, the math (but apparently not my math...) shows that rated should be > 32 mph for the Ideal setting then it indeed might be a bug if the UI is showing less for the Ideal version of the UI.�
Dec 22, 2012
FlasherZ It's been noted, we don't have full access to all 85 kWh, there is still a question as to whether there is a reserve, etc. I just use 300 because it's what Tesla seems to use.
You have a unit problem (change kWh/mi to Wh/mi at the end).
Either way, 40A delivers far more than 20 mi/hr of charge regardless of whether you use 280, 300, or 320 Wh/mi.
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I'm not going to continue to overanalyze the math because it will make me cross-eyed this late at night and we don't have all the necessary variables, but I have come to three conclusions that I can make:
1. Showing 20 miles per hour of charge is clearly wrong, regardless of which math you use or mode (rated vs. ideal) you're in. That was the OP's primary argument. In fact, you only begin to approach 20 mi / hr of charge when you get to 208V @ 30A, a far cry from the OP's 235V @ 40A. Could this perhaps be a leftover of the "projected" math?
2. The ideal miles per hour of charge should be higher. I really don't care about ideal miles, because I'm currently averaging 400 Wh/mi anyway. That's because I drive like an idiot: a smiling, happy, gleeful idiot. But for those people who like to drive the model S like the average Prius driver (slow with no go), ideal should show a higher ideal miles per hour of charge.
3. Based on my experience, charging my car @ 245V, 40A yields ~31-32 rated miles per hour of charge. While I don't know how Tesla derived that number in the first place, it happens to be correct.�
Dec 22, 2012
brianman Heh, tired. I'll fix that. Fixed.�
Dec 23, 2012
Fedderman This what I have noticed when charging off the 14-50 in my garage: When first connected, the voltage reads around 240-243 Volts at 0 Amps. As the charging current ramps up 40 Amps, the voltage drops to around 230-233 Volts (~10 V drop). Is this typical?�
Dec 23, 2012
montgom626 I don't have my MS yet ;-(. Seems like it ramps up, peaks and then ramps down as battery is reaching max charge????�
Dec 23, 2012
Mphmd I believe you've adopted my driving style !�
Dec 23, 2012
FlasherZ Yes, higher currents cause higher voltage drops across wiring (since wiring has resistance). The voltage drop is dependent upon the type of wire used (Cu/Al), the length of the circuit, the wiring gauge, and in some cases the load on your home service. 6% is considered the maximum recommended drop, and you're within that. Anything more, and I'd go looking for the reason.�
Dec 23, 2012
cinergi Not unheard of ... might be a little on the abnormal side but probably nothing to worry about unless you have heat building up somewhere. Let it charge for an hour and check all your connection points (plug, breaker, etc.)
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He's talking about observed voltage sag during charging -- nothing to do with tapering off.
The Model S does taper the amperage as it reaches 100% but that's ONLY in a range-mode charge when talking about NEMA14-50 charging. It doesn't taper during normal standard mode charging (from a 50-amp, 40-amp-draw circuit like a NEMA14-50)�
Dec 23, 2012
FlasherZ If the drop is voltage is under 10%, you really don't have to worry about heat. At that current, you'd have a serious voltage drop if something were generating heat. A 10V drop is only a 250 milliohm resistance at 40A. #6 copper has about 500 milliohm resistance per 1,000 ft, so 250 mohm would point to a total (round-trip) circuit size of 500 ft, or 250 feet (one-way) from the panel.
The only other contributing factor could be a heavily-loaded transformer, or near-capacity on service wiring. To troubleshoot further, you'd want to measure voltage at the breaker panel main while the car is charging. If your voltage drops to 230V across the buss when the car is charging, it would point to more of a service / transformer load issue than circuit length.
Either way, 10v is nothing to sneeze at. It's within the 6% typically considered to be "normal".�
Dec 23, 2012
montgom626 Actually, I was talking about charging varying changing based upon SOC.�
Jan 10, 2013
Jack I've been charging for 5 hours with 22 MPH displayed - 14/50, 228, 40 - similar to everyone else. I've charged a bit over 150 miles in the 5 hours, so it does seem to be a 4.0 display bug - thanks for alerting Tesla.�
Jan 12, 2013
Adstein Today was my first charge using a Nema 6-50. Had 80 miles left and started the charge. Within a few minutes I was getting 31mph charge with amperage holding at 40 and 237-240V.�
Jan 12, 2013
colinb Plugged into a NEMA 14-50 at home I noticed this (mind you this was near the end of the charge):
I would expect at 31 mph charge would work out to 50 km/hr. I never have bothered to watch too closely but with a 300km trip coming up I'll be sure to pay a lot more attention.
(while we are at it if Americans would kindly sign the petition to convert to the metric system it would be easier for us Canucks to compare without a calculator on hand.�
Jan 12, 2013
FlasherZ 39A @ 232V is 9.05 kW. That's about 28 miles per hour of charge with 10 kW being 31 miles per hour, or 45 km/hr. Your car has 13 km to full standard-mode charge (I think), and is reporting 20 minutes remaining (or 1/3 of an hour). That comes out to 39 km/hr (close to the 38 it reports). Is some of the power going to other systems ?�
Jan 12, 2013
brianman FlasherZ's post acted as a good reminder that I wanted to double-check this after the 4.1 update.
Rated: 26mi/hr, 237V, 40/40A while at 63mi SOC
Ideal: 32mi/hr, 236V, 40/40A while at 73mi SOC
I'm using a NEMA 14-50R.�
Jan 12, 2013
FlasherZ That's what I see too, but that may not line up with the charging time. Subtract your current rated miles from 240, then divide by number of hours remaining. For example, 2 hours 30 minutes is 2.5. When I do the division, I always end up with the full 30-31 miles per hour of charging, although the display shows 22-26. And because the charge finishes on time (at least from the few times I've watched it), that has to be correct.
Can you give me a photo of the large screen while it's charging?�
Jan 12, 2013
mknox Ugh... please don't.�
Jan 12, 2013
brianman I didn't get home until after most of the charging was done. Nonetheless, in case it's useful here's the 17".
Random observation: I didn't notice 'til now that this UI is showing the wrong wheels for my vehicle. The rendering is also missing the spoiler.�
Jan 13, 2013
montgom626 North Americans? South Americans? Central Americans? ;-)�
Jan 13, 2013
FlasherZ You're too close to a full charge, but that's reflecting 28 mi/hr if you consider 7 miles are left to charge in 15 minutes (7/0.25). 39A at 240V is 9.36 kW. 31 * .936 is 29 mi/hr of charge.�
Jan 13, 2013
brianman I think the charge target is 238.5 (90% of 265), and the math lands a little closer in that case.
But yah, it's pretty close to full so may not be useful for your purposes.�
Jan 13, 2013
mark This is what I am getting:
Still seems like I am not getting 31m/hr - even with "ideal" voltage and current.
240-191 = 49/1.75 hr = 28m/hr�
Jan 13, 2013
brianman From your screenshots, "+2 mi" means you just started. IMO, you need at least "+20 mi" or "+30 mi" before the "mi/hr" estimation is past the "ramp up" stage.
I routinely see "20 mi/hr" (Rated) within the first few minutes of plugging it. After more time (10m?), it elevates to "26 mi/hr" (Rated).�
Jan 13, 2013
mark Thanks - I have checked later on but still never seen over 23mi/hr. I will keep watching it - only had the car a week.
Also - sorry about the double image in my first post - thought I deleted this first one.�
Jan 13, 2013
brianman Edit, Go Advanced, Manage Attachments, Click one of the Xs in the bottom left
Hope this helps.�
Jan 13, 2013
Fedderman I believe you need to change your setting to display Ideal instead of Rated, if you want to see the Ideal charging rate.�
Jan 13, 2013
aviators99 The weird thing is that I have mine set to Rated, and I see 29/30/31 every day.�
Jan 13, 2013
cinergi You all ignoring me? :smile:
Here's what I've said & believe: it depends on what version of software you're running and what setting you have selected. I believe it's doing the wrong thing in 4.x. In 3.x it depends on rated/projected; when set to rated it displays the proper value.�
Jan 13, 2013
Fedderman Good point - behavior is likely dependent on SW version. In my case, I am on 4.1, and the charging rate adjusts between Rated and Ideal, pending on the settings.�
Jan 14, 2013
aviators99 I am running 4.1 - x.x.29.�
Jan 14, 2013
FlasherZ I agree with this too.
I said earlier in the thread that I thought they baselined it in the wrong mode. It should have been baselined in Rated mode, then the multiplier added to increase it in Ideal mode. Instead, I suspect they baselined it in Ideal mode and then applied the ratio which would give the wrong numbers for both of them. It should be 31 rmph or 37 imph of charge, roughly.�
Jan 14, 2013
Todd Burch FlasherZ, I remember that you responded to me when I first posted about this after receiving my car, believing something about the baseline is incorrect. I am on v4.1 (1.19.31), and I have seen 30 MPH charge rate, pulling 239V and 39-40A using rated mode.
In other words, same as aviators99.�
May 30, 2013
scaesare While I am also a pedantic SOB, I'm primarily responding to this post because it was referenced in a recent thread, and it contains much good info that folks in the future may want to review, and the above text (emphasis mine), might be a bit confusing.
Given that the 10V voltage drop in the example IS WITHIN acceptable limits, it IS something to sneeze at... that is, I believe FlasherZ was saying don't worry about it even thought that's not what the phrase above tends to mean.
That having been said, thanks FlasherZ for the great info... now back to your regularly scheduled programming.�
May 30, 2013
FlasherZ Thanks for that. My new baby was born November 30 and I use the excuse of sleep deprivation.�
May 30, 2013
scaesare Congrats on the other ? baby.�
May 30, 2013
FlasherZ Thanks. Both came in the same week.�
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