HPWC Energy Usage?

[Stevedore]

Just wondering if I’m misunderstanding something here regarding my MYP’s energy usage.

All of my charging is done at home via my Tesla Wall Connector @48 amps. (Actually, I did try a supercharger once for 15 minutes or so when I first got the car to make sure I knew what I was doing).

My car has 3239 miles on it & shows Total Energy usage as 957 kWh, resulting in 296 Wh/mi. Seems rerasonable, based on what I've read here & elsewhere.

When I query my wall connector with "http://wall.connector.uri/api/1/lifetime", substituting its IP address for “wall.connector.uri”, I get the following report:

{"contactor_cycles":79,"contactor_cycles_loaded":3,"alert_count":3,"thermal_foldbacks":0,"avg_startup_temp":27.1,"charge_starts":79,"energy_wh":1408681,"connector_cycles":44,"uptime_s":16034694,"charging_time_s":373001}

If I understand this correctly, the report shows that my connector has used 1408681 watt hours since new, corresponding to approximately 435 Wh/mi, which seems like a huge disagreement with the wall connector usage.

What am I missing here? Does that “energy-wh”: 1408681 not indicate the total electricity used by the wall connector?

Thanks for any explanation!

 

[cubicalclang]

I think so too. I'd also like to think that you would notice a change in your electric bill to the tune of another 1,000 kWh or so a month.
As a spot check you could wait for a time when your house consumption is unchanging. Disconnect the TWC at the breaker and note the home power at your meter, and then plug in the TWC and note any increase. 1.5 kW or anything near that should be obvious.

Well, I didn't do the disconnect at the breaker thing yet but I have been monitoring the usage all week.

I charged Sunday night into Monday morning and my lifetime energy_wh went from 860,164 to 886,681, 26.5 kWh, matching the car very closely, and more importantly, the charge time. The lifetime charging_time_s stat right now is reading 175,621. The last time I paid attention to that was in my last post and that was 167,319, a delta of 138.37 minutes which actually aligns pretty close to the last charge I did on Sunday night (2.3 hours @ ~ 11.17 kWh =~ 25.8 kWh).

Now, the weirdness again. Didn't charge the car Monday night, Tuesday night, Wednesday night. Lifetime energy_wh didn't change all week. Until today, Thursday. Today the lifetime energy_wh went up 26.5 kWh exactly, from 886,681 to 913,181. Without the car having been plugged in all week. The car is going to charge tonight (well, Friday morning at 0100 as that's when I have the car start to charge).

So, I will report back in the morning.

I think this weekend I will definitely play with the breaker for the wall charger to see what happens. 26.5 kWh over three days (these unexpected changes only seem to happen in the morning, or overnight I guess) is still a heck of a lot more than 25W continuous consumption if this is real energy consumption (I still think it's not, my electric bill is very much inline with charging usage; electric bill went up about 50US per month when we got the car).

 

[SageBrush]

I think this weekend I will definitely play with the breaker for the wall charger to see what happens

Reading meters is easy once you know how it works. Find your meter with an internet search to track down the revolutions/Wh

Have fun

 

[cubicalclang]

Reading meters is easy once you know how it works. Find your meter with an internet search to track down the revolutions/Wh

Have fun

I have an electronic meter. But, not a smart (connected) meter. So it's even easier than that.

Last night added 42.7 kWh, my highest charge ever. Time delta was 13,153 s or 219.22 minutes, which lines up within 1% of expectation at 11.5 kWh charging rate. Session charge data says 42,679.102 which is slightly different than what the lifetime says so that's interesting (lifetime stat delta for last night was 42,719, a difference of 39.898 wh, which over the charging period is a difference of 10.9 watts. So that doesn't line up with someone who said 25 watts earlier in the thread but they may have a different charger (mine's a Gen 3 WC and it's very close to my router). Hmm...

 

[andaconda]

I use an app called Wall Connector for all that information

 

[cubicalclang]

I use an app called Wall Connector for all that information

Why use an app when you can just get it directly from the charger? Still, none of the API data gives an indication of how much power the charger itself is using.

 

[andaconda]

Why use an app when you can just get it directly from the charger? Still, none of the API data gives an indication of how much power the charger itself is using.

I’m too lazy to do the math myself.

 

[cubicalclang]

No weirdness overnight last night. If it's consistent it might be tonight, and then not again for a few days. Will be interesting to see if it repeats, and/or if it's the same amounts.

 

[cubicalclang]

No weirdness last night either.

 

[cubicalclang]

Oh oh oh!! I figured something out I figured something out I am so pleased with myself. To be clear, I know the WHAT. I don't know the WHY. Though as I've already said I think the why is "because a software bug".

So check it out.

I mentioned in my last post that there was an odd discrepancy between what it showed on the "session_wh" under the "Vitals" API data and what it had added from the last charge "Lifetime" API data entry "energy_wh". The last time it did the random growth thing I thought the number seemed similar to what the charge was but I didn't record the data thoroughly enough. This time, I did. The last session charge was 42679.102 (from "session_wh") but at the time the "energy_wh" number had gone up by 42719. Well, today, the "energy_wh" number went up randomly again...and it went up exactly 42679. (Note too, while I didn't definitively record the data last time, looking back at the data I do have, the last time I charged before this I charged 26517 wh and the "random" number the charge went up a few days later was 26500 so this is good correlation).

So, it seems like a couple of days after I charge, it double counts the last charge and adds it to the "lifetime_wh" number. It doesn't seem to do this every time - the Tesla app says I've charged 702 kWh at home; the lifetime "energy_wh" is now 998,579. So, maybe it started with some software update? My wall charger firmware is 22.45.1+(a whole bunch of alphanumeric characters I'm not going to repeat in case they're unique).

I'm going to keep watching it. This is a weird one for sure but at least I have an idea of what exactly it's doing now.

 

[cubicalclang]

Ok so yesterday I got the random add again. It duplicated my charging from Wednesday. Wednesday my charge (increase) on lifetime energy_wh was 48253, on vitals session_wh was 48226.5. When I checked the lifetime energy_wh yesterday it had gone up again, and the delta was 48227 (it rounds up to the next watt hour apparently; when session_wh was 42679.102 it gave me 42679; now that it was 48226.5 it gave me 48227).

What I didn't expect was the add to come yesterday. I thought it would come Friday overnight into Saturday based on past history. It might also be some number of hours because I'm not consistently checking it at the same time.

Wonder how I could report this to Tesla. Any ideas?

 

[insaneoctane]

Thought I'd throw some data to help. I've got a new Gen3 installed with 5 charges on it so far. The lifetime energy_wh is confirmed to be wrong because I also have an energy monitor dedicated to this EVSE line. No question that it's wrong by a lot. In the 5 charging sessions (which the vitals session_wh seems to track individual sessions well), my EVSE monitor shows I've used 126.3 kWh, yet the lifetime energy_wh shows 338.2 kWh. The EVSE monitor is CT clamps, so I'm comfortable it's correct. I'm not sure why the HPWC is double counting (or whatever it's doing), but it's not accurate and can't be used as an accurate cumulative until Tesla fixes it or one of us figures out how to adjust it (if that's even possible).

EDIT: I do track the data quite closely and am seeing the double/triple counting too. At the end of my 4th charge, my lifetime energy_wh was 255952. At the beginning of my 5th charge, my lifetime energy_wh was 322645. The difference is 66693. The vitals session_wh final value for my 4th charge was 33346.2. If I double 33346, I get 66692.4. This indicates that the vitals session_wh was added a total of 3 times (instead of once) to the lifetime value before I started my 5th charging session. Tesla must have some buggy code that inadvertently adds final values more than once. Shame. Anyone know how to report this issue???

 

[insaneoctane]

Another comment on this thread. I discovered that you have to “disconnect” the HPWC plug from your vehicle to reset the session_wh number. Two days ago I plugged in my vehicle and it charged for about 7.5kWh which was accurately reflected in the session_wh number. Never drove the car that next day. I decided to increase my state of charge for a longer trip for the next day and bumped up the charge from 70% to 75% and drove away the next morning. I just looked at my HPWC data and was surprised that the first charge to 70% and next day charge to 75% were combined in the session_wh because it wasn’t disconnected. Just FYI for anyone trying to log the data and use session_wh to calculate totals…. I have 2 entries for 2 logs from 2 different days. First day is 7.5kWh, the second is 11.2kWh, but it should have been 7.5kWh and 4.7kWh (11.2 is cumulative for both days)

 

[cubicalclang]

So obviously I haven't posted in a bit but I wanted to provide potentially a "final update". I've charged three times since the above and my Gen 3 wall charger has not done the session_wh addition since 17 MAR. In that time I did reach out to Tesla about "hey I think there's a bug in the charger data" and they asked me for details and screenshots so I provided a write-up and screenshots. On the first expected time for the duplication not happening, my firmware was the same, so they hadn't done anything. I do know that I didn't have enough instances where I gathered good data to establish a pattern, just had a guess and the number of days after a charge where the addition would occur varied.

However, I note that I do now have new firmware in my charger. When I contacted Tesla with the write-up my firmware, and this was still true this past Monday morning, was 22.45.1+g917e6d67600e64 (from the firmware screen in the API links). Now, it is 23.8.2+gce13e49b546382. So that's potentially a substantial code revision going from a version 22.x to a version 23.x. (Oddly the wall connector troubleshooting page still lists firmware 22.41.2.)

I charged overnight; will keep an eye on it again closely the next few days just to see what, if anything, happens.

 

[insaneoctane]

Does the HPWC auto upgrade firmware or do you need to initiate it?

 

[Sophias_dad]

Does the HPWC auto upgrade firmware or do you need to initiate it?

It auto upgrades if it has a wifi connection. There are also some reports that it can upgrade from the car(if the car has been updated).

 

[Evertvdw]

Glad that I found this topic. I just started reading out my Gen 3 wall connector as well, and the total energy_wh does not make sense for the amount of KM I drove 1700km and it said it had charged around 470 kWh, which is not very efficient. I'm monitoring the sessions now, and will see if they correctly add up now. I only charged in april so far and I just checked and the firmware is at 23.8.2.

 

[insaneoctane]

So obviously I haven't posted in a bit but I wanted to provide potentially a "final update". I've charged three times since the above and my Gen 3 wall charger has not done the session_wh addition since 17 MAR. In that time I did reach out to Tesla about "hey I think there's a bug in the charger data" and they asked me for details and screenshots so I provided a write-up and screenshots. On the first expected time for the duplication not happening, my firmware was the same, so they hadn't done anything. I do know that I didn't have enough instances where I gathered good data to establish a pattern, just had a guess and the number of days after a charge where the addition would occur varied.

However, I note that I do now have new firmware in my charger. When I contacted Tesla with the write-up my firmware, and this was still true this past Monday morning, was 22.45.1+g917e6d67600e64 (from the firmware screen in the API links). Now, it is 23.8.2+gce13e49b546382. So that's potentially a substantial code revision going from a version 22.x to a version 23.x. (Oddly the wall connector troubleshooting page still lists firmware 22.41.2.)

I charged overnight; will keep an eye on it again closely the next few days just to see what, if anything, happens.

@cubicalclang , My HPWC updated to the newest FW on 3/22/2023....When did you supply Tesla your write-up and screenshots?

 

[insaneoctane]

Just sharing. The latest firmware still has some lifetime_wh issues. On 4/12/2023 using firmware_version=23.8.2+gce13e49b546382, I had my lifetime "energy_wh" jump 30 kWh in 2 minutes when I viewed my logs. I believe it occurred in the middle of a charging session that had a brief pause/anomaly. The session values reset during this time, so I really had to sleuth my logs/data to figure out what was going on since both session and lifetime totals were wrong from what they should have been.

 

[esurt]

Just found this thread after seeing an incorrect value of "energy_wh" on my newly installed (UK) Wall Connector. If I look at last night's charge stats in the Tesla app the 13.2kWh is exactly half of the increase in "energy wh" from yesterday to today!

Just wondering if anyone ever found a solution to this. I'm on firmware 23.8.2.

Also, somewhat related, I'm keen to better understand the idle consumption of the wall connector. If I calculate idle energy usage using current data available via the /vitals API I get >200W, but this seems too high and I'm not sure how accurate those current values are anyway. But, if I try to calculate idle power by looking at "energy_wh" over a period of a number of hours, I don't see an increase at all. So, I'm wondering, does "energy_wh" not include idle usage? Anyone any idea? How have others determined idle usage?

I was planning not to install a separate energy meter and hoping I could get data from WC API's but not looking very positive

 

[Sophias_dad]

If I look at last night's charge stats in the Tesla app the 13.2kWh is exactly half of the increase in "energy wh" from yesterday to today!

I'm not sure I understand. Does something say you used 26.4kwh of charging? I can tell you without a doubt that if anything like even 100 watts is used by the wall connector body itself it will literally be ON FIRE. >Maybe< if you add the dissipation of the cable you could get another 50 (1V times 48 amps), but that's about it.

To 'lose' 13200wh you are talking about 24 hours of 550W continuous dissipation. Absolute poppycock.

Add to that the fact that the charge cable losses are only when the vehicle is charging(which would be what... 6 hours tops before an empty battery is full?) and the two relays that do a very large portion of the dissipation in the HPWC are also fully deenergized when its not actually charging. The idle current into the charger is(I'd wager) no more than 3W, and even when actively charging, the HPWC+cord losses are probably around 75W or less. The relays typically have resistive losses on the order of 13W, and there are two of them. Gen3 HPWC disassembly, with overheating issues explained! has some information about the relay dissipation.