Help me diagnose possible high wh/mi highway usage

[geordi]

First - please do not suggest "just drive slower!" as an answer. Because not one of us bought these to do 50mph on the highway, and that is completely unrealistic in our modern society. It's likely to get someone run off the road. I have not changed my driving style from one vehicle to the next, and my highway cruising is long distances over frequently traveled routes, so I can SEE where the power usage has changed over time. It actually was lower when it was COLDER.

I'm asking for suggestions / places to look / things to try, and if there's anything I can check with ScanMyTesla or Tessie, I'd be happy to.

2016 X 90D. Battery currently showing 14.3% degradation, 224 rated miles at 100%, Tessie thinks the real world is 180. ACTUAL is more like 140. So there's either a mismatch in the BMS or there's something else going on. Cruising highway speed FLAT LAND (Florida, Georgia, SC, NC) is pushing 500 wh/mi. No that should NOT be that high. Previously driving the same route, power usage right after I bought this X at the same speed was around 375.

I've seen north of 500 wh/mi while towing (ok, that makes sense) but on the same trip in the plains, with a tailwind, was seeing 650. So this feels like something that is changing or turning itself on and off rather than something mechanical. Not towing right now, I'm seeing 470-500.

I've had the half shafts replaced, changed to a set of Tsportline wheels (and I can feel that they are definitely lighter than the stock setup) with slightly narrower tires (255) that are the same diameter outside as the 20" wheel setup. No extra electrical loads inside, no inverter (so that's all ruled out). AC is on, refrigerant load is exactly correct according to the sticker. ~25 and ~200 for refrigerant pressure with the system on. Ohmmu battery now.

Virtual support hasn't been terribly helpful, suggesting that I needed to replace the 12v battery and the coolant pump - but no mention of which pump, and there are no errors for anything there. The only errors I have seen are related to the falcon door calibration, an RCCM actuator, PresSnsDis (climate pressure sensor?) and now a new one that it is "unable to charge" on AC, when it still is charging just fine.

That unable to charge message (CHG_f018) started right after replacing the 12v battery, so maybe having everything powered off made it detect it. I swapped the 12v batteries around and that error is still there, and it's only been for the last few days. So I don't think that's related.

So.... Where to look next? Ideas please!!!!

 

[scottf200]

Obviously some serious drag on the system with 500 Wh/mi (at what speed 80mph?).
- played with tire pressure? I'll let my hit 49-ish PSI when roadtripping in a hot location. I think 50 is on the tire which is cold pressure.
- unclear on what tires you currently have and had in the past? lot of friction on tires
- last time brakes were checked ... last times clean and lubed to verify zero dragging
- thermal -- you can do a thermal check see this A/C only works in Park. Hot smelly air when driving

 

[scottf200]

Re: tire friction
My Conti OEMs vs Michelin Cross Climate 2s for Wh/Mile comparisons at diff speeds.

 

[geordi]

Obviously some serious drag on the system with 500 Wh/mi (at what speed 80mph?).
- played with tire pressure? I'll let my hit 49-ish PSI when roadtripping in a hot location. I think 50 is on the tire which is cold pressure.
- unclear on what tires you currently have and had in the past? lot of friction on tires
- last time brakes were checked ... last times clean and lubed to verify zero dragging
- thermal -- you can do a thermal check see this A/C only works in Park. Hot smelly air when driving

Current tires are the CC2, actually when on that towing trip I had the 245/45/19 CC2 set on OEM rims from my S, so significantly shorter and a 5mph (reading higher than real) speedo discrepancy. Was towing at 75/80 actual, the trailer is a 6x12 aluminum open flatbed with a total of about 800 lbs loaded.

Current tires are speedo-accurate, 255/55/19 on the Tsportline 19" rims. I ran the towing trip at 60 PSI, these are at 45 at the moment to try and work one variable at a time. Original tires were factory staggered 20" rims (for sale!) with Michelin treadwear 220 tires - I don't remember which specific but I didn't like the wearing away. I know there's possibly a friction penalty - BUT treadwear 220 tires are like glue, what's the spec of the OEMs from your chart?

I have replaced the wheel bearings (prior to the towing trip) but have not done anything with the brakes. I probably should, b/c I hate how much dust the OE pads make. I don't *think* they are dragging though.

Alignment has been done (N2itive all the way around) and is near perfect.

Thermal test - you mean from the service menu? I did get an error about the temperature sensors at the end of that list. No errors about that in the alert screen though... Only the one about the RCCM actuator. I DID see a pressure sensor error but that was new yesterday, not when this thermal test was done.

 

[NewbyMaybe]

Acceleration uses the most juice, I increase my range by staying near the back of the pack and not trying to get to the red light first. Also letting off the pedal when I see the light changing or traffic backing up.
Highways reduce range, staying right with the slow folks helps.

 

[geordi]

Acceleration uses the most juice, I increase my range by staying near the back of the pack and not trying to get to the red light first. Also letting off the pedal when I see the light changing or traffic backing up.
Highways reduce range, staying right with the slow folks helps.

I didn't say I did stoplight racing, and this is talking about power used changing (increasing and never decreasing) at the same speed on the highway over multiple trips.

So your advice is "drive slower" which I specifically said "First - please do not suggest "just drive slower" as an answer!

If two identical highway trips over the same route with the same load at the same speed have considerably different power usage - Speed wasn't the change. Thanks for playing though.

 

[scottf200]

(a) what's the spec of the OEMs from your chart?
(b) Thermal test - you mean from the service menu?

(a)
Continental CrossContact LX Sport; Crossover/SUV Touring All-Season; ContiSilent Front 265/45R20 108V XL UTQG: 480 A A
Continental CrossContact LX Sport; Crossover/SUV Touring All-Season; ContiSilent Rear 275/45R20 110V XL UTQG: 480 A A

Note the CC2 are not efficient if you look across the internet. Mine have not be awful (higher PSIs helping?) but after reading I expected worse.

(b) yes, I pointed you to a post that showed it

FYI, the post I pointed you to was a person having thermo issue on their 2016 X 90D too.

--- I think you have drag somewhere you haven't found. Or you have some parts/equipment using extra. Scan-My-Tesla with AC on/off; parked overnight; etc type of test for current kw used.

 

[geordi]

The power usage of the compressor is the only thing that I've found that seems out of line - Scan My Tesla and the dash display agree that on high (11) fan which moves considerably LESS air than my Model S.... The compressor seems to be sucking down about 4kw! The fans themselves for the front and rear are good for about 350 watts each - which seems excessive for the size, but that's another matter. 4000 watts for a compressor... I have an RV air conditioner that is a 115v unit at 15000 btu, that only uses 1500 watts at full blast. That's WITH the blower on that too. So 4000 just for the compressor seems excessive.

I evacuated and recharged the system (after vacuuming to almost 30 inches) without opening the system to atmosphere, so I know it has exactly the amount of refrigerant it is supposed to have. I do not believe it has a leak and is frosty cold most of the time when driving. Every once in a while it DOES seem like the air gets "stale" and you can tell the compressor is off - but it comes back on soon after so that may just be normal cycling.

Where is the temperature sensor, do you know?

 

[oldsport]

that is very high wh/mi readings...
mine...
@55mph 230 wh/mi
@70mph 290 wh/mi

 

[geordi]

that is very high wh/mi readings...
mine...
@55mph 230 wh/mi
@70mph 290 wh/mi

What year is your X? What size tires / wheels? I know the newer ones get substantially better power economy, but not really sure why.

 

[zoomer0056]

If two identical highway trips over the same route with the same load at the same speed have considerably different power usage - Speed wasn't the change. Thanks for playing though.

So, what has changed to increase Wh/m? What events happened, when did the change happen, was it gradual or instant? Sorry, more questions like these might not be helpful. But i am just thinking out loud. You've looked at and tried a lot of things so far without a clear answer. Two things come to mind. Condition of an old BMS/battery system that's been pushed to its limits (towing and other high usage). And, what does the Energy App show as consuming all that power. There are two battery service vendors that frequent TMC, ask them about how condition of BMS/battery could cause the high Wh/m numbers. One other note, you layed out rules on how people should respond to your request for help. Here is another rule, don't be so quick to snip at people trying to help you.

 

[geordi]

So, what has changed to increase Wh/m? What events happened, when did the change happen, was it gradual or instant? Sorry, more questions like these might not be helpful. But i am just thinking out loud. You've looked at and tried a lot of things so far without a clear answer. Two things come to mind. Condition of an old BMS/battery system that's been pushed to its limits (towing and other high usage). And, what does the Energy App show as consuming all that power. There are two battery service vendors that frequent TMC, ask them about how condition of BMS/battery could cause the high Wh/m numbers. One other note, you layed out rules on how people should respond to your request for help. Here is another rule, don't be so quick to snip at people trying to help you.

Thinking out loud is great - that helps figure out a root cause, thanks! The only "rule" was to not tell me that the solution is to drive slower - and since I haven't changed my driving style or speed, yet the power usage has changed, speed isn't the cause or the answer. I'm not expecting it to get 200 wh/mi at 80. (Of course that would be amazing if it did though!)

This has been a progression over time, but I've also put 20k miles on the car in the last 3 months. Spring and fall are my busy seasons, and obviously I drive a lot so I'm able to see the change over time and try to rule out causes. Instant would be a lot easier to nail down a direct cause.

I bought this in February, and was able to get at least a baseline of this particular vehicle's performance then. I also noted at the time that there was a bearing noise, which is why I replaced all four bearings. Unfortunately the energy app doesn't provide detailed breakouts in the older cars. I think it COULD.... But Tesla hasn't programmed that option in for this generation. My 2014 S doesn't show it either.

I don't think the issue is with the battery - that would certainly affect the total power available, but not how quickly it is being consumed. The consumption side of things is a separate issue. That's not to say there isn't maybe an issue with the drive motor or AC compressor where that is using more power, or the coolant heater or battery thermal system that is keeping the battery warm when it doesn't need to... SOMEWHERE there's a system that is misbehaving, but it either isn't out of scope enough to throw an error.... OR it is a mechanical system that isn't monitored. I THINK the only mechanical system I haven't done yet is the brakes. I guess that's going to be next.

 

[zoomer0056]

I THINK the only mechanical system I haven't done yet is the brakes.

I wonder if after a drive looking good at rotor temp would reveal anything. You can still inspect brakes and rotor for abnormal wear. I'm at a loss, keep us informed.

 

[Pied]

A quick way to check brake drag is put your hand near the wheels after a drive, it would feel hot/warmer than the others.

 

[geordi]

OK… So dropped my X off for falcon wing door issues, and I have a loaner. It’s a 3/2017 X 75D on 22” wheels - I think they are OE but not 100% on that. What it IS - is another datapoint on this search and since I’m the one driving it on the same roads that I drive mine…. Now that eliminates two other possible variables.

Driving the thing back, at 80mph on I-95 for 50+ miles…. 375-385 wh/mi.

That is right in line with the baseline of my X from right after I bought it, when it had factory 20” wheels. The previous owner said he had gotten rid of the 22” wheels (that this loaner has) because the power usage was hurt so much… So I’m wondering how badly MINE is being hurt by having even lighter Tsportline 19” wheels! That change would be all about the wheel weights and I KNOW that the OEM 20” are some heavy buggers.

They are going to have mine for a couple days at least…. So I will probably have a chance to poke at this one some more. Supercharging it now so that I can get a health report on the battery from Tessie. That’s a damn cool feature of that program FYI….

 

[geordi]

Continuing on with this thread - The loaner X has a new 350v battery, my X has the original 400v.

I have noticed that the AC fan in this loaner seems nearly as capable at moving air as in my Model S, where the X at 11 is about like the S at 7 or maybe 8 on the blower speed. Not sure if that means that a blend door is stuck or what... Or maybe the fan is using more power than it should. I need to do more research on that. I am probably going to have this loaner for at least a few more days, the list of what they are working on has gotten longer and way more expensive. *grumble*

 

[brainhouston]

First - please do not suggest "just drive slower!" as an answer.

Drive slower jk jk couldn't resist haha
While im not gonna tell u that, to establish a good known data point for apple to apple comparison, try driving at least 30mi in Chill/Range mode n under 65mph
That will help determine if ur usage uptick is linear or not...

Unfortunately the energy app doesn't provide detailed breakouts in the older cars. I think it COULD.... But Tesla hasn't programmed that option in for this generation. My 2014 S doesn't show it either.

The function is in the app for legacy cars under service menu
I've made a post about it

Vehicle range analysis in app under Service menu

While its nice to check how you compare to EPA, does anyone know how to reset it? I did analysis after i drove to work on 21st, it finished (see below) I tried on 22nd, it did its thing n showed same results for the same trip (even though i had longer trip there)... Now its 23rd, same results...

teslamotorsclub.com

I have noticed that the AC fan in this loaner seems nearly as capable at moving air as in my Model S, where the X at 11 is about like the S at 7 or maybe 8 on the blower speed. Not sure if that means that a blend door is stuck or what... Or maybe the fan is using more power than it should. I need to do more research on that. I am probably going to have this loaner for at least a few more days, the list of what they are working on has gotten longer and way more expensive. *grumble*

Maybe cabin filter...
If u have bio mode u have huge filter behind frunk tub n small in cabin somewhere
I've never replaced mine yet but on ICE cars i frequently knew "its time" when AC cooling would be weak

From scouting n reading threads on here for a while, i think biggest impact to Wh/mi is toe..
If its grossly out either way, it kinda acts as brakes, dragging tires a bit sideways..
I just use two square dowels n 2 clamps from Homedepot to quickly check toe, car needs to be on ramps not lift. 1/16in seems to be the best...

My drive to work this morning (25mi) at 65avg was 325Wh/mi w/ AC n 22in wheels
My best was 310, my 1k mi ave rn is 360
Hope this helps.

 

[geordi]

Hmm - I do have the bio mode, I didn't know there was still a smaller filter. Gonna have to dig around for that one.

The alignment is just about perfect, don't know how to do it myself - but I saw the numbers and they were near zero, so I don't think the toe is an issue. This has N2itive adjustable arms all around, so that helps.

 

[brainhouston]

Hmm - I do have the bio mode, I didn't know there was still a smaller filter. Gonna have to dig around for that one.

The alignment is just about perfect, don't know how to do it myself - but I saw the numbers and they were near zero, so I don't think the toe is an issue. This has N2itive adjustable arms all around, so that helps.

Yeah its behind glove box i think...

N2itive is for camber, Doesn't affect range, just tire wear.
I was suggesting for sanity check, just to make sure paper agrees with actual wheel measurements.

I can't find a video on youtube but here's how i do it:

Red is square dowels (1/2 or 3/4, not sure) and blue is clamps
Go under car, touch to rims on either side, clamp it, then move to opposite side to see the diff, might have to redo depending which side is shorter.

 

[Richbot]

I'd get it aligned again, somewhere else, just to be sure. All zeros but thrust angle off and you've got a big range problem crabbing down the highway

The only other simple, non-powertrain related thing it can really be is a dragging brake, which you can check with a cheap IR pyrometer after a highway drive for a few miles, check for temperature difference. Unlike the later cars, you actually have to use the brakes almost every time you drive on the older cars, so they get a lot more use yet still don't get much use to dry them out and keep them free

Parking brake servo ought to throw an error code but, also worth a check