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Estimating the actual electricity used by Model 3

I was curious how to best convert the kwh in trip meter to the actual kwh off the wall. I googled and found the following topic:

Model 3 showing wrong kWh consumption?

It appears that the take home messages are:

1. Tesla's kwh usage does not take into account the energy used for pre-heating etc. That's a big chunk of energy missing from the trip meter based on my two months experience with SR+. Pre-heating the car eats a lot of % of battery.

2. 1.25x minimum to convert the kwh in trip meter to the actual electricity charged off the outlet.

Right now based on the trip meter I got 300wh/mile with total of 825kwh used over 2750 miles. I pay $0.175/kwh at home so my cost of electricity is 0.175 x 825 x 1.25 = $180.

My old car @ 19.5mpg and $3.5 premium gas would cost $490 over 2750 miles. Good to know I saved $300 and hopefully once the summer comes the savings will grow bigger.
Why would you need to estimate when there is a tool like TeslaFi out there? Lots of great data gathering including home and supercharger charges. Enter your electrical rated and Teslafi.com does everything else.

Check it out with a free trial- use bsietz as your referrer and get an extra few weeks.



Active Member
Nov 22, 2018
I estimate my consumption by comparing electric bill/usage on days that I charge my car vs no charging days.

Here's what I do:

Find average House Consumption on No-charge days (Sat/Sun) ~ 15 kWh.

Charge only during off-peak rate (to have constant cost factor), start 1200 midnight that day (MTWThF). Average House Consumption (including EV charging/preheating) ~ 60 kWh.

So, 60 kWh - 15 kWh = 45 kWh per commute day.
I drive about 160 miles per work day, hence 45 kWh.

Other than that, Im sure there are Apps/meter that you can hook up to your Wall Connector/Charger to get exact energy sent to the EV.

Yup, as per Brian - TESLAFI is the App you are looking for.
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Supporting Member
Mar 3, 2019
I installed an inexpensive watt meter that gives me actual watts used. From Amazon. I can’t remember the cost, but it’s around 20 bucks. I use Teslafi as well.


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This difference is greatest in the depths of winter when you tend to use cabin pre-heating extensively.

Yeah. I found that it can cost me almost 1% battery for every couple minutes of pre-heating and I can easily use 5% batter if I preheat for like 10-15 minutes. That's like 2.5-3 kwh which is about $0.5 electricity. Doing this twice everyday it can add up quite quickly.

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