Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.

Help with Power Meter and Vampire Drain


Mar 24, 2020
Racine, WI
I bought excitedly a new Model S LR in Dec 2019. Have a Tesla Wall Charger running from the breaker panel. Still learning about charging limits, battery degradation, phantom braking, vampire drain, ghost cruise, monster space, etc. from these discussions. I am running 2020.32.3.
Need help on two fronts please:
(1) What is the good value-for-money approach to know reliably how many kW I am actually pumping into the car when I plug it in? For security reasons I prefer not to use 3rd party software like Teslafi.
(2) The vampire drain surprises me! For 10 days I had not moved my Tesla out of my garage (lovely weather so used my Miata a lot). . but the charge level dropped from 85 to 68%! That is 17,000Wh consumed in 240hrs which is 70Watts drained each hour. Sounds realistic?? Very surprised/disappointed. Sentry Mode is off; relatively cool temperatures in upper midwest. What's going on? At 17kW-hr per 10 days drain, am I looking at 50kW-hr of vampire drain per month, or half-a-tank of electricity poof every month! Wow.
Thanks for any help. . .


Active Member
Aug 31, 2019
Springfield, VA
You've painted yourself into a corner by eliminating the best option for this: TeslaFi. You could install a power monitoring piece of equipment called Sense in your panel. That will give you intel on how much power is coursing through your home's circuits, including the circuit for your wall connector. Of course that costs a lot more than TeslaFi and provides a lot less detail on your car's energy use, though it has other benefits in your house.

I burn through 1.5 - 2.5 kwh per day of vampire drain. I think a big part of that is because I am constantly polling the car with TeslaFi and I do not allow the car to sleep (it's annoying to wait for the screens to boot up). I find it's a convenience worth shelling out a few bucks a month for.


Sep 5, 2020
Santa Clarita
There are wall chargers available from companies other than Tesla that record the energy consumption during the charge event. I personally use a OpenEVSE unit that has a readout on the EVSE and can communicate with a webapp. I know there are also units available from Enel X and ChargePoint that also have webapps, but I'm sure they aren't the only ones.

Alternatively you can set your car to notify you when it starts and stops charging. Mine tells me the starting battery percentage and ending percentage when it charges. That would give you an indication of vampire consumption but will be less accurate than the EVSE with a current transducer but is much cheaper.



Oct 29, 2020
I have the same sort of quantum - 2020 LR and with a power meter on the charger spur it's showing a consistent 2.2 KwH per day sitting with the charger plugged in while in the garage with everything off (unpaired Bluetooth, Keys in faraday, no apps connected). Seems pretty excessive.

Products we're discussing on TMC...

About Us

Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.

Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.