Supercharging slowing down...heat?

[CoolColo]

So I recently took my 2018 LRM3 on a road trip from DFW to Colorado Springs (750 miles, mostly at posted speed limit - 75mph). This is 5 charge stops, 3 V3 (Amarillo, Clayton, Trinidad) and 2 V2 (Henrietta, Childress). I noticed a new behavior this trip (I make this trip several times a year). The charge session would quickly ramp up to full speed - 150 or 250kw depending on the charger - then within a minute or so start falling to well below the "normal" charge speed - hovering below 50kw. So for example, I would be at 50% SOC and only charging at 40kw. Certainly not the normal taper. It was very frustrating to be at low SOC and charging slower than my Chevy Bolt! Often I was the only or one of only a few cars at the chargers, and I didn't share a V2 with another vehicle.
I suspect this was heat - the day was warm but not crazy hot - like in the 80s or low 90s. But I'm not sure if this is battery heat, or the charger (handle?) over heating.
Is there a way (through OBDII?) to tell why a charge session is being throttled?

 

[GtiMart]

You can use ScanMyTesla with the proper CAN adapter to see the battery temperatures, things like that, and try to infer a reason.

Had you preconditioned while going there? It is possible that your battery got too hot, with great preconditioning and then possibly imperfect cooling from your car while charging. I've had issues where my car would shutdown as I entered the highway right after supercharging, which is another cooling issue. If it were only V2 chargers I would have said that maybe the handle got hot, this happens and I've seen a youtuber wrap it with a wet-ish rag to help cool it down. But V3 cables are water-cooled so that shouldn't happen. You might have hit one bad charger but not all of them.

Was your cooling system running like crazy, fans blasting on full? Was your cabin cooling lacking during that time? Have you ever cleaned your car's front radiator?

 

[CoolColo]

Yes, the cooling was running full blast and seemed to run longer after I finished charging than usual. The cabin cooling worked fine, however. I haven't cleaned the radiator since the AC works fine. Is that a common issue? I'll check to see if it's looking gungy.
The car did pre-condition on the trip N, but on the return trip I intentionally didn't use navigation to prevent preconditioning. It might have made a slight difference, but it wasn't dramatic. I don't think I have enough data points to make a guess here yet.
Oh and I did notice that the V3 handles in Clayton NM were very warm...so maybe the cooling loop is having problems at that location.
Thx.

 

[804son]

The temperature sensor in the handle may have gotten too hot, If you suspect this, you can wet a rag and wrap it around the handle to cool it, and get better charging speed.

 

[CoolColo]

Ah Ha! GtiMart nailed this I think. I followed the directions in the video below to get into the radiator heat exchanger/condenser area, and mine looked much like in the video with lots of leaves and bug parts on top of the condenser. HOWEVER - I found there is a clip on the drivers side that holds the condenser in place. By unclipping this, I was able to separate the condenser and the radiator heat exchanger just enough to peek between and the ENTIRE space was packed with bug parts, leaves, and grass. Apparently junk collects on the top of the condenser then works its way down between over time. The condenser covers something like two thirds to three quarters of the radiator heat exchanger and I'd estimate airflow through that area was 80% blocked by gunk. An hours work with a 1/8 metal rod that I bent a small hook into the end of, plus the shop vac, hose and coil cleaner and I had the gunk mostly vanquished.
My only test so far has been one V3 SC session, and it went very well, maintaining 85kwh even above 75% SOC - a personal best. But it was only 82F at the time, and this wasn't a road trip. The real test will be the next summer trip when I can heat soak the battery with multiple charge session and hard driving. I'll let you know. But at this point, I would say anyone experiencing slow SC sessions or unusual charge tapering (especially on hot days) might take a look at their radiator hea... oh screw it - radiator. I know I'll be servicing mine annually now, and probably get one of those grill mesh thingies too.

 

[GtiMart]

I've done mine preemptively once I learned about this. Fortunately it wasn't very dirty but it's something I now keep in mind. Our cooling systems are a very important part of our cars.

 

[CoolColo]

So here's the final on this saga.
I was recently able to repeat the road trip from the first post. Sadly I found the charge tapering behavior returned, even though this trip was much cooler than the first - ranging from about 50f to 80f. This time I was also armed with an OBDII scanner and the Scan my Tesla app.
I noticed several things
1. On a V3 charger, the battery would quickly heat up to 150f. The radiator fan would start running around 135f, but clearly was unable to prevent the battery temps from rising. I could not hear the coolant pumps running at this time.
2. Once the battery rises above about 145, the car reduces charge rate for thermal protection.
3. Once charging had completed, the radiator fan would continue to run for a long time - sometimes over an hour. Watching the battery temps on OBDII showed the battery temp dropped very slowly - taking over 30 minutes to drop from 150 to 130f. Clearly there was no active cooling, nor passive cooling through the radiator. It was simply the battery losing heat through he casing.
4. If I felt airflow through the radiator (removing the frunk cover), it was warmer than ambient IF I had the AC turned on, but if I turned off the AC, the air was no longer warmer than ambient. This is with the battery at 150f. So clearly coolant wasn't being moved through the battery or radiator.

So the car went in for service - sure enough the "super bottle" was bad. Total repair: $1200, on a car with 59k miles. It's out of warrantee, so that's all out of my pocket. The service rep said it's not bad for a car with 60k miles to be coming in for its first repair (!!!!), and he's seen super bottles replaced at 25k miles. What?
If I'm looking at new cooling components every 25-50k miles, needless to say this has changed my opinion of the car. This is especially concerning since the health of the battery is degraded every time the temps climb unchecked. Thermal management is what separates Tesla from the Leaf in terms of battery longevity.

My tip to any Tesla owner - if you see charge rate throttling, or notice changes in how your car sounds while or after charging (no longer hear some whining pumps, or radiator fan stays on a long time) - get your car to a service center. You will have NO INDICATION (warnings, CEL) from the car that something is wrong. Don't listen to the internet "experts" telling you this "just happens" sometimes because of the charging station was busy or the handle gets hot or the phase of the moon. I put off this service longer than I should have because of those "experts" and I lost some capacity because of it.

 

[GtiMart]

Thanks for reporting back. This is one great example of the need to get more information in the car. If you had charging rate and temperatures, as well as some information like other manufacturers have started providing stating whether the charger is limiting current or not, you could have at least understood that your car is not performing at peak.
- voltage and amps requested : kW
- voltage and amps received from charger : kW
- message if charger is limiting power. Ideally why (hot handle vs grid load or charger sharing etc) if possible
- battery temperature
- Optimal charging curve, or at least optimal kW the car should be requesting at current SOC
- conditions to obtain optimal charge (target battery temp etc)

With all of this, you would have known the car wasn't requesting as much as it should and would have seen a hot battery. Not all of these are essential, and they could be hidden behind an "advanced mode" switch, but they are useful. Tesla are doing exactly the opposite and hiding as much as they can in the name of making it simple and appealing to everyone. I don't think it helps.

EDIT: About your tip. If everyone that sees some apparent throttling (not that you can know since you don't know the charging curve and it can change with a software update) does a service request, the service centers will be even more overloaded and will never be able to serve other problems properly. Worse, they will most times just return you home (because it's a normal situation) and everyone will be frustrated.

 

[CoolColo]

Agreed, more info - optional for 'advanced' users - would be great.

The proper solution however, IMO, is an alert. The car had all the info it needed - ambient temp, battery temp, battery inlet temp, and what "mode" it was in - to estimate expected temp delta through the cooling system. If that number is outside of an expected range (or 0), that's a problem. The car has no "thermal authority." Simple.

As for people taking in their car for charge throttling. Here's my problem. If I didn't regularly use V3 chargers on long trips, I never would have noticed this. Basically my car had NO BATTERY THERMAL MANAGEMENT FOR SEVERAL MONTHS - it was a passive air cooled battery like a Leaf, and we all know how those batteries fare. So how many people with "commuter" Teslas have bad cooling systems? We don't know. But according to the service advisor, my problem wasn't surprising. In fact, he's seen this in cars with as few as 25k miles. If he had said this was a rare problem, I wouldn't be writing this paragraph.

So if your car is warm and you're on a V3 or unshared V2 charger, and you see your charge rate take a rapid dive and settle well below "normal" - what I call "unusual throttling" - that's the only sign of failed cooling system. I'd make an appointment.

 

[AlanSubie4Life]

Agreed, more info - optional for 'advanced' users - would be great.

The proper solution however, IMO, is an alert. The car had all the info it needed - ambient temp, battery temp, battery inlet temp, and what "mode" it was in - to estimate expected temp delta through the cooling system. If that number is outside of an expected range (or 0), that's a problem. The car has no "thermal authority." Simple.

As for people taking in their car for charge throttling. Here's my problem. If I didn't regularly use V3 chargers on long trips, I never would have noticed this. Basically my car had NO BATTERY THERMAL MANAGEMENT FOR SEVERAL MONTHS - it was a passive air cooled battery like a Leaf, and we all know how those batteries fare. So how many people with "commuter" Teslas have bad cooling systems? We don't know. But according to the service advisor, my problem wasn't surprising. In fact, he's seen this in cars with as few as 25k miles. If he had said this was a rare problem, I wouldn't be writing this paragraph.

So if your car is warm and you're on a V3 or unshared V2 charger, and you see your charge rate take a rapid dive and settle well below "normal" - what I call "unusual throttling" - that's the only sign of failed cooling system. I'd make an appointment.

Definitely very strange that the car provides no warnings in this case. As you say should be relatively easy to detect, and the car can take some time to verify the failure before telling the driver. No need for hair trigger response.

Did they say exactly what went wrong with the Superbottle? Actuator failure or something?

 

[KenC]

So here's the final on this saga.
I was recently able to repeat the road trip from the first post. Sadly I found the charge tapering behavior returned, even though this trip was much cooler than the first - ranging from about 50f to 80f. This time I was also armed with an OBDII scanner and the Scan my Tesla app.
I noticed several things
1. On a V3 charger, the battery would quickly heat up to 150f. The radiator fan would start running around 135f, but clearly was unable to prevent the battery temps from rising. I could not hear the coolant pumps running at this time.
2. Once the battery rises above about 145, the car reduces charge rate for thermal protection.
3. Once charging had completed, the radiator fan would continue to run for a long time - sometimes over an hour. Watching the battery temps on OBDII showed the battery temp dropped very slowly - taking over 30 minutes to drop from 150 to 130f. Clearly there was no active cooling, nor passive cooling through the radiator. It was simply the battery losing heat through he casing.
4. If I felt airflow through the radiator (removing the frunk cover), it was warmer than ambient IF I had the AC turned on, but if I turned off the AC, the air was no longer warmer than ambient. This is with the battery at 150f. So clearly coolant wasn't being moved through the battery or radiator.

So the car went in for service - sure enough the "super bottle" was bad. Total repair: $1200, on a car with 59k miles. It's out of warrantee, so that's all out of my pocket. The service rep said it's not bad for a car with 60k miles to be coming in for its first repair (!!!!), and he's seen super bottles replaced at 25k miles. What?
If I'm looking at new cooling components every 25-50k miles, needless to say this has changed my opinion of the car. This is especially concerning since the health of the battery is degraded every time the temps climb unchecked. Thermal management is what separates Tesla from the Leaf in terms of battery longevity.

My tip to any Tesla owner - if you see charge rate throttling, or notice changes in how your car sounds while or after charging (no longer hear some whining pumps, or radiator fan stays on a long time) - get your car to a service center. You will have NO INDICATION (warnings, CEL) from the car that something is wrong. Don't listen to the internet "experts" telling you this "just happens" sometimes because of the charging station was busy or the handle gets hot or the phase of the moon. I put off this service longer than I should have because of those "experts" and I lost some capacity because of it.

Very informative and I'm sorry that you got charged for the super bottle pump failure. Is that ultimately what it was? A super bottle pump failure?

I'm wondering if there's something in SMT we can directly keep an eye on. I suppose the temps would be one way, since a pump failure would lead to passive cooling and temps would soar out of target range under the right conditions, but unless you get those conditions, you might never notice. How about pump failure?

If the pump failed, would the battery and powertrain flow show zero liters/minute?
Then there's this chart:

Which could tell you the temps of the powertrain and battery.
And then there's also this chart, which shows the target temperature range, but doesn't seem to show any pumping info:

 

[AlanSubie4Life]

Very informative and I'm sorry that you got charged for the super bottle pump failure. Is that ultimately what it was? A super bottle pump failure?

I'm wondering if there's something in SMT we can directly keep an eye on. I suppose the temps would be one way, since a pump failure would lead to passive cooling and temps would soar out of target range under the right conditions, but unless you get those conditions, you might never notice. How about pump failure?
View attachment 869117
If the pump failed, would the battery and powertrain flow show zero liters/minute?
Then there's this chart:
View attachment 869118
Which could tell you the temps of the powertrain and battery.
And then there's also this chart, which shows the target temperature range, but doesn't seem to show any pumping info:
View attachment 869119

Yeah seems like the coolant flow metrics would be off which is why it is odd that there was no warning about this. Seems easy to detect no coolant flow, unless somehow this is dead reckoning based on a Superbottle setting, rather than a measurement.

 

[CoolColo]

The powertrain and battery flows did not show anything unusual - my guess is those are the "commanded" numbers not measurements from a sensor. My car, when it failed, would show battery temps near 150f, Passive and Active Cooling at 103, and Battery flow ~25lpm (full blast) and yet the battery wasn't really cooling at all. (it's also worth noting I've never seen battery flow and drivetrain flow differ.)

As for the exact failure, below is the full report from the service invoice. You will note the tech starts off with "Nothing appears to be wrong" - but then OH WAIT - "5 way coolant valve actuator fails thermal system test and self test. Tech also found excessive debris between the fan and radiator restricting air flow and A/C system Chiller EXV to have an internal fault. At this time tech cleared debris restricting air flow however 5 way coolant valve and chiller exv require replacement due to an internal failures."

The bit about the debris is only half correct - as I said much earlier in this thread, I had already cleared the debris myself (and yes there was a lot). I also re-checked the radiator after the service, and it wasn't noticeably cleaner.

And then he follows up with "Advise customer that replacement of 5 way coolant valve and chiller exv will NOT improve or affect kW during charging and will only improve thermal system operation."
What? This is BS. Maximizing charge rate depends heavily on thermal system operation. What the tech did NOT do while testing the battery was getting it hot enough for THERMAL throttling to kick in. This appears to be somewhere around 145-150f, and it's not easy to get there unless you're highway driving. You need a loooooong time for preconditioning to get the pack to 130f, then use a V3 station from a low SOC. Tech didn't do this.


Concern: Customer states: Charging - Battery cooling problem. When charging on v3 chargers (especially on warm days) charging speed ramps up to 250kw briefly, then rapidly drops to about 40kw, even when SOC is below 40%. Cooling fan then runs for very long time - like over an hour, sometimes it's still running when i arrive at the next supercharger while traveling. This behavior started this summer but has continued into the cooler days.

Tech Reports:
Tested super charging operation and reviewed customer provided time stamps and no charging issues where found. Tech tested and compared kW with another good known model 3 vehicle and found kW to be the same while charging vehicle alone at the super charger and also found the kW to drop down the same amount when both vehicles where super charging at the same time. Tech also found both vehicle operate the condenser fan equally. Advise customer that kW will change depending on the super charger and how many super charges are being used at the charge station at this time charging system is operating as designed and no issues are found. Advise customer the vehicle will run exterior condenser fan as cooling is needed during super charging and during a/c operation. However Multiple thermal issues where found during service that could affect cooling operation. 5 way coolant valve actuator fails thermal system test and self test. Tech also found excessive debris between the fan and radiator restricting air flow and A/C system Chiller EXV to have an internal fault. At this time tech cleared debris restricting air flow however 5 way coolant valve and chiller exv require replacement due to an internal failures. Advise customer that replacement of 5 way coolant valve and chiller exv will NOT improve or affect kW during charging and will only improve thermal system operation. See line 5 for repair details if repairs are approved.

 

[CoolColo]

View attachment 869117

How about pump failure?
View attachment 869117

I'm envious of your 77kwh Nominal Pack Full number. Mine is 65.8 on a 2018 with 60k miles (I went from 69.0kwh to 65.8 just during this thermal failure incident.)

 

[Dave EV]

I'm envious of your 77kwh Nominal Pack Full number. Mine is 65.8 on a 2018 with 60k miles (I went from 69.0kwh to 65.8 just during this thermal failure incident.)

My 2018 with 36k is at 67.6 kWh according to scanmytesla, so basically the same. Your is probably slightly higher due to the higher miles.