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HPWC Energy Usage?

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Stevedore

Stevedore

Member
Aug 8, 2021
48
43
NJ
#1
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!
 
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#3
Stevedore said:
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!
Click to expand...
Where did you get that URL to query? I haven't seen it before.
 
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#4
Stevedore said:
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!
Click to expand...

Like jcanoe said, that figure represents the total consumed from the power company.

But I'm fascinated to learn how to poll the HPWC! I just tried it. The is the first time I've gotten it to respond to anything while on our house WiFi.

Do you know any other queries besides "lifetime"?
 
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#8
Adding to this thread 1 year later....
Has anyone seen a way to use the HPWC Gen 3 API/webpages to differentiate which vehicle is plugged in? I've now got 2 Teslas and would love to be able to collect usage for each, but need a way to poll/query and know which of my vehicles the last charge was associated to...TIA
 
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#9
I'd like to pull the thread here too as well. Post #2 states (obviously) the Tesla only knows how much power it has received / used, not how much power the Wall Connector has delivered. What that post fails to notice though is that the difference isn't 5 or 10% in the Wall Connector API, it's 47% higher in OPs case. I am seeing similar in my Wall Connector that was installed in January; unfortunately I only learned that these API calls exist last weekend.

In my personal case the "energy_wh" number in my Gen 3 Wall Connector, if I use the average consumption of my car, says it's delivered enough energy to drive 832 miles further than the car odometer reading - a 32% difference. If I look just at Charge Stats in the Tesla app it says my 2023 charging has been 517 kWh vs. the Wall Connector stating 824 kWh lifetime (it was installed on January 3) - that's a 61% difference (now, there were two days in 2023 where I charged before I had the Wall Connector installed; this however would actually make the delta look better; also, I charged twice at Volta free chargers, but that was a total of only 3 kWh)! What I'm wondering is if the Wall Connectors are delivered with some number already populated in the "energy_wh" column, like from factory testing during production, and this is skewing the numbers? Also, the session_wh number aligns exactly to what the car says, so is that actually delivered energy or is that actual energy use?

I've searched high and low on the internet about this and no one seems to be speaking about it. This kind of a discrepancy, if accurate, ought to be serious serious news, so I personally think something else is going on here. I'm definitely going to pay very close attention to this from now on though.
 
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#11
ATPMSD said:
I think the problem is the source of the 957 kWh figure, where did that come from?

My connector shows a consumption of 4 mWh. If I divide this by the 165 cycles it shows this equals 24 kWh per session, which is about right.
Click to expand...
My WC data says I have averaged just over 37 kWh per charging session in 22 charging sessions (assuming that’s what contactor closures represents as you said). The problem with this is I’ve only charged as much or more than 37 kWh three out of 22 sessions. The highest only being 41. My sessions are usually in the 20 kWh range. So, the average doesn’t make sense.
 
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#12
Hey just for anyone checking back I can definitively say the Wall Connector Lifetime status "energy_wh" does not represent only charging output. Why do I say this? Because, I didn't charge my vehicle overnight, I didn't even plug it in, but the Wall Connector has reported a growth in the Lifetime "energy_wh" data from 824 kWh that I reported yesterday earlier in this thread to now 860 kWh. The Vitals "session_energy_wh" didn't change from my last charge cycle (Thursday night) so it looks like that at least is accurate.

It's got to be seriously bugged to think it used 36 kWh simply sitting there on Wi-Fi with the cord not even plugged in to the car. Looks like this data has no value to me.
 
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#14
I can think of a few extra energy drains that the TWC will count that the car will not:

1. Cabin pre-conditioning when connected to the TWC
2. Pack pre-conditioning when connected to the TWC
3. Charging losses (around 10% on a 240v connection)
4. "Vampire" losses to keep the TWC/Wi-fi energized.

(1) and (2) are very much climate and user dependent
 
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#15
ATPMSD said:
In my experince the wall connector draws about 25 watt / hr when idle, which is about 600 watts / day.
Click to expand...

You meant 600 Wh a day.
Your measurement of 25 watts is interesting. I hope it is not that high, but I'm reminded that my local utility does not offer rebates for the Tesla EVSE. I was told a couple of years ago that they go by a list of energy star listed (or some equivalent list) products, and Tesla has not sought certification. I suppose it is possible that the TWC does not meet their criteria, but that is just idle speculation ... unless it really does draw 25 watts since I think the threshold is 20 watts.
 
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#16
SageBrush said:
You meant 600 Wh a day.
Your measurement of 25 watts is interesting. I hope it is not that high, but I'm reminded that my local utility does not offer rebates for the Tesla EVSE. I was told a couple of years ago that they go by a list of energy star listed (or some equivalent list) products, and Tesla has not sought certification. I suppose it is possible that the TWC does not meet their criteria, but that is just idle speculation ... unless it really does draw 25 watts since I think the threshold is 20 watts.
Click to expand...
Could be less, this is based on data before we got access to the lifetime energy stat, I will need to recheck. But my problem is my unit rarely responds to a query from a local network so getting the stat is very hit or miss. Very odd, but heck, this is Tesla.
 
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#17
ATPMSD said:
In my experince the wall connector draws about 25 watt / hr when idle, which is about 600 watts / day. I question the 36 kWh figure. Did your “lifetime energy_wh” figure really grow by 36,000?
Click to expand...
You can question it, but that doesn't change that yes, I looked at the numbers yesterday to write my earlier post, and I looked at the numbers today to write my immediate prior post, and there was a massive delta between them, and I didn't even have our car plugged in.

I'm going to be checking it twice daily for a while to see what is going on with it.
 
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#18
cubicalclang said:
You can question it, but that doesn't change that yes, I looked at the numbers yesterday to write my earlier post, and I looked at the numbers today to write my immediate prior post, and there was a massive delta between them, and I didn't even have our car plugged in.

I'm going to be checking it twice daily for a while to see what is going on with it.
Click to expand...
My question supports your concern, 36 kWh is a huge amount to consume when nothing is plugged in.
 
Last edited:
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#19
ATPMSD said:
My question supports your concern, 36 kWh is a huge amount to consume when nothing is plugged in.
Click to expand...
Agreed. I don't think it used that power though. I think it's a bugged data field.

And here's another data point I hadn't considered - it has in the lifetime stats a "charging_time_s" which seems clear to be interpreted as number of seconds actively charging. We know the Model 3 Long Range and Performance are 11.5 kW capable, and my wall connector is showing 232.8V so 11.174 kW @ 48 A. My total charging time in that parameter is 167,319 s or 46.48 hours, which if you do the math is 519,367.52 WH, which is vastly lower than what the charger says in its "energy_wh" field (still 860,164) BUT this is much more in line with what the car reports in terms of overall energy ever received (689 kWh but that includes the three weeks in 2022 before I had the wall connector and a big supercharging session totalling 172 kWh which when you do the math again leaves 517 kWh in 2023 which is *really* close; I put a combined ~10 kWh into the car on Jan 1/2 over two level 1 charging sessions; this gives 509 kWh which is 1.9% less than 517 kWh....98.1% efficiency which is certainly possible).

All this to say, data supports that "energy_wh" either comes with some value in it, or it is bugged like I think it is. I guess I'll see tomorrow what it changes to after charging overnight.
 
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#20
cubicalclang said:
Agreed. I don't think it used that power though. I think it's a bugged data field.
Click to expand...
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.
 
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