High electricity draw when Model 3 is plugged in?

[chopdlck]

Hi all,

I live in an apartment building that has recently raised charging fees from $50 to $80/month for high electricity usage. This shocked me as the actual costs of electricity should not be this high given my usage.

Some Facts:

• Electricity fee here is $0.13/kwh
  
  
• The setup is 3 charging outlets (NEMA 6-50) that is connected to a single meter. No other devices are connected.
  
  
• Only two ports are being used, both the other owner (also model 3) and I are using our mobile adapters that came with the model 3s.
  
  
• The hourly electricity data shows that there is a constant 0.2 kwh draw no matter what,
  
  
• There is also random spikes to ~1.2 kwh for a few hours occasionally in the night when the cars should be charged. It is probably closer to 1 kwh after accounting for the passive draw. This "Phantom Drain" has gone as high as 5.45 kwh in feburary when the temperatures was around 4 Degrees Celcius outside (we're in a non heated underground parkade so the temps should be a bit higher)
  
  
• Some graphs i quickly made with the data. Imgur: The magic of the Internet
  

For August alone, the passive 0.2 draw and the 1.2 kwh phantom draws account for 52% of the total energy used.

I do not have full access to the Hydro data and the other owner does not wish to participate or help in my investigation.

My theories: - Faulty electric meter for the .2 CONSTANT power draw - Phantom spikes caused by cars preconditioning or the other tesla.

Any insights or theories is greatly appreciated. BC Hydro charges $90 bucks to get meter tested so im gonna try to be sure before going through with it.

 

[Tessaract]

Hi all,

I live in an apartment building that has recently raised charging fees from $50 to $80/month for high electricity usage. This shocked me as the actual costs of electricity should not be this high given my usage.

Some Facts:

• Electricity fee here is $0.13/kwh
  
• The setup is 3 charging outlets (NEMA 6-50) that is connected to a single meter. No other devices are connected.
  
• Only two ports are being used, both the other owner (also model 3) and I are using our mobile adapters that came with the model 3s.
  
• The hourly electricity data shows that there is a constant 0.2 kwh draw no matter what,
  
• There is also random spikes to ~1.2 kwh for a few hours occasionally in the night when the cars should be charged. It is probably closer to 1 kwh after accounting for the passive draw. This "Phantom Drain" has gone as high as 5.45 kwh in feburary when the temperatures was around 4 Degrees Celcius outside (we're in a non heated underground parkade so the temps should be a bit higher)
  
• Some graphs i quickly made with the data. Imgur: The magic of the Internet

For August alone, the passive 0.2 draw and the 1.2 kwh phantom draws account for 52% of the total energy used.

I do not have full access to the Hydro data and the other owner does not wish to participate or help in my investigation.

My theories: - Faulty electric meter for the .2 CONSTANT power draw - Phantom spikes caused by cars preconditioning or the other tesla.

Any insights or theories is greatly appreciated. BC Hydro charges $90 bucks to get meter tested so im gonna try to be sure before going through with it.

1. If there is a constant 200W (.2 kW) draw with nothing connected to the circuit, then the meter is faulty. But more likely something actually is connected to the circuit and nobody knows about it. Carefully tracing the wiring might reveal what this phantom power thief is.
2. Electrical power consumption spikes when "cars should be charged" are inconclusive. Teslas can power up for a number of reasons (accessing the mobile app, sentry mode alerts, automatic AC/heating events, etc.) so these spikes can easily be real. Relying on "cars should be charged" to argue no spikes should occur is faulty logic. The fact this "phantom drain" increases in cold weather is further indication that the car is autonomously turning on some heating, resulting in the spikes.

 

[Tessaract]

Had a closer look at your Imgur graphs: unless I don't know how to read graphs, they actually don't show a "a constant 0.2 kwh draw no matter what". There are many hours which don't show this .2kWh consumption. The fact that this .2kWh consumption is not, in fact constant, is further indication that something like bullet 2 in my reply above is happening.

 

[pcons]

Do you have Sentry mode on?

The car has a constant draw of around 60-70W, known as Phantom drain. Maybe they have improved it since I measured it a year and a half ago, but with everything 'off' your range still go down 10 km/ 24 hour day while parked. (10 km x .15 wh/km / 24h = 62.5 W)

One thing I wish we could do is turn everything off. My wife's bolt and my previous 2 volts could sit for weeks without losing 1 km of range, but tesla keeps
minimal computer power on for monitoring, ota updates, etc. Especially these days in losing almost as much range through Phantom drain as I am actually driving since I'm largely working from home and not going into the office.

Having Sentry mode on bumps this draw to seeing 200W if I remember my calculations correctly, so my guess is that Sentry mode is on white you are plugged in. Doing quick math, in about 8 hours while at work with Sentry mode on expect to lose around 14 km of range, so 14km x .15 wh/km / 8 h = 262 W.

There is also some battery conditioning that can periodically happen depending on the outside temps.

I think you are seeing a combination of those two things.

 

[GtiMart]

You charge your car at home? For reference it costs me 30-50$ per month of electricity to charge my car and I dont drive that much. All charging done at home, and I pay around 10c per kWh here. Cost reported by TeslaFi. Since you pay your electricity 30% more than me, if you drive a bit, the addl cost seems reasonable to me...

 

[chopdlck]

Thanks for the responses. I do no use sentry mode, nor does the other owner.

@Tessaract - The really tiny dark blue lines in the top graph of the second photo is the hourly draw, you can see that it is continous throughout the graph.

I've unplugged the adapter from the wall for the past week and did not charge my car at all to see if the adapter is the cause of the .2kwh draw.

 

[mrElbe]

A red herring is that the other owner does not want to participate in your investigation. He or she might be the consumption culprit. You not charging all week will prove that one way or the other.

 

[Tessaract]

Thanks for the responses. I do no use sentry mode, nor does the other owner.

@Tessaract - The really tiny dark blue lines in the top graph of the second photo is the hourly draw, you can see that it is continous throughout the graph.

I've unplugged the adapter from the wall for the past week and did not charge my car at all to see if the adapter is the cause of the .2kwh draw.

I'm thinking the vertical tiny red lines labelled as "phantom drain"in the legend is the relevant info. And those do not appear constant... there are many intervals with no red lines.

 

[chopdlck]

Sorry should have been more clear, the passive drain is the .2 kwh drain, the phantom drain is the 1kwh drain that happens randomly at night, even with the cars (my car at least) being fully charged. When the cars are actually charging, it spikes to much higher kwh usage ~4-6.

 

[camalaio]

I honestly can't make much sense of your graphs, sorry.

What is the original (not re-interpreted or scaled, etc.) output of the meter? Is it the one-hour energy totals? How much precision does it have? (hopefully the meter states its accuracy somewhere)

If two Mobile Connectors were plugged in but not powering the car, data from others suggests this is about 6W. Over the hour, that's 0.006kWh, nowhere near 0.2kWh (or 0.15kWh, assuming the 0.2kWh is rounded for example).

The... "phantom spikes"? are a normal part of owning the car unfortunately. It likes to wake up to do various things, and is one of the most wasteful EVs in this regard. For low mileage commuters, this can actually become a very significant portion of your energy usage. Using anything that keeps the car awake as a feature (Sentry Mode, Summon Standby, Cabin Overheat Protection) will add to this greatly. All that said, it's weird how consistent they are. This standby power is normally between 150-350W - even if both cars were doing this at max, that's only 700W, not 1200W as it seems to be. So that implies some larger load, perhaps climate control related like Cabin Overheat Protection (at least for these August numbers).

The numbers don't make sense to me at all, but we also don't know what the other person's car is configured for either. For example, the parts where charging is implied don't make sense - I'd expect you're both pulling the 32A maximum and this is probably a 208V building, which should be 6.6kW or so. However, there are power draws all over the place - 2.0kW, 3.2kW, 4.0kW, 7.8kW, and only a couple very brief bouts of ~6.6kW. It's like one (or both) of you is constantly varying your charge current? Or perhaps the car is? This doesn't make any sense.