I'm new to this and was wondering how to calculate charging costs. Looking on my electric bill, we pay:
1,000.000 kWh x $0.06329 (over 1,000.000 kWh x $0.07051).
How do I figure out cost per mile/kWh/etc?
I also downloaded Stats for Tesla and there is a place in the settings for my energy cost. I assume I just enter 0.06239? Is that correct? The local Supercharger is 0.31, so just wanted a sanity check since the cost is so much higher.
Thanks for the n00b help.
Mostly what others have said. Your rates are so low that the costs are going to be low. Make sure you include all the transmission and distribution fees. I thought usually in Oregon the total cost per kWh was closer to $0.10/kWh but maybe not.
Anyway, whenever you have that, just take your Wh/mi in the car, and in summer multiply by 1.2, and in winter multiply by 1.4.
So if you have 230Wh/mi on your lifetime in-car meter, your actual costs are probably about:
1.2*230Wh/mi*$0.10/kWh = $0.027/mi
This is assuming you drive about 10-15k/yr.
The 1.2 is to account for charging losses (12%) (and the vampire drain). The 1.4 number is to help account for preheating, etc that you may do in winter (the 1.4 factor may be calibrated to a colder winter environment than Oregon, so you might do better - depends on whether you garage your car, etc.). These are just rough approximations. The important thing is to not calculate costs directly based on the in-car meter - it needs to be scaled up. Less scaling is needed when using Superchargers, as they are inherently more efficient from plug to battery (direct DC). Obviously there are conversion losses built into the high Supercharger rate; they are not magic. (I have no idea how Tesla bills, but presumably only for the energy actually delivered to the battery, in which case it is effectively “100%” efficient.)
For the Stats app I think it does some of this scaling for you when calculating your costs, but I have not paid attention to it (EDIT: just checked, Stats appears to use a scale factor of 1.12 - which is about right for charging efficiency and aligns with the 1.2 number above (as it is scaling up the actual kWh added to the battery, and not using the in-car meter, so already includes vampire drain in the pre-scaled number - so a smaller scale factor can be used). I also cross checked with Chargepoint app and the calculated $ from Stats align pretty well with the Chargepoint numbers if I convert the Stats $ to kWh using my specified Stats rate. Can’t actually compare $ directly since the CP is free to me. You don’t want to use the Stats kWh numbers to compare because that is energy added to the battery, not the energy from the wall.
(For calculating costs all that matters is what you draw from the wall, not what is on the meter in the car or what is added to the battery.)