Can I please get some feedback on whether this comparison is valid? I did some searching and browsing here and on Tesla's site and didn't see a clear answer (possible "ebcak").
I charge my car nearly every night in the garage. On a single trip after unplugging, I see distance traveled and Wh/mi. Multiplying these gives me units of energy consumed (E_c]. Also, my range estimate next to the battery icon decreases by X. X*78.27 kWh/310 mi (EPA rating for 2018 LR AWD) is also units of energy, amount decreased in actual battery (E_d).
As long as I'm not using energy while parked, E_d should equal E_c, correct? (Assuming E_c does not display parked consumption, please let me know if this is dis/proven). My car has E_c about 76% of E_d rather consistently, which seems like something is really off (and also indicates even in the summer with HVAC off my lifetime best consumption was never below 266 Wh/mi actual battery drop, which is crazy in comparison to people I see averaging in low 200s). The service center wants to focus the conversation on what affects consumption rate, even though I try to communicate the battery capacity is what seems off.
Are my assumptions/expectations invalid? If so, can someone please point out to me the why?
You can look at the posts elsewhere (the Constant sticky is a good place to look).
Your first equation should use 76kWh and 325rmi (to give you 234Wh/rmi). Remember you got an unlock.
The E_c does not include energy used in park, that's correct.
In short, you only have 95.5% of your total battery energy available between 100% (your full rated miles) and 0%. This is a key thing to remember when doing these calculations if you want to do them.
And your full battery energy, including buffer below 0 = Vehicle Constant * Rated Miles @ 100%. (Since you have a 2018 RWD that constant is 234Wh/rmi)
Finally, the trip meter seems to typically read low (shows less energy consumed than actually consumed) by about 1%, though it can also read high in the right circumstances (temp changes, etc., etc.). These are small discrepancies though compared to the first point. So E_d and E_c as you define it (after making corrections above) will differ by that very small %.
As an example, let's say you start at 290 rated miles.
You drive 50 miles at 266Wh/mi. Your trip meter says you used: 13.3kWh.
That's a little (1%) low as I said, so 13.3kWh/0.99 = 13.43kWh was the actual consumption, probably.
Since each displayed rated mile is not 234Wh/rmi, but instead 95.5% of that, each displayed rated mile is 223Wh.
So you'll see 13.43kWh/0.223kWh/rmi = 60rmi tick off, so you'll end at 230 rated miles for this trip.
And remember after you hit 0 rated miles, if you drive really slowly and carefully, you'll be able to drive (perhaps, if you're lucky) and use that final 4.5% of your battery. (Don't do this.) But unless you do that you'll never see the full battery energy on your trip meter (it'll be short by 4.5%). That buffer is 4.5% of your full pack energy.