Hi,
@devsters,
I hope you are otherwise enjoying your Model 3.
First and foremost, the biggest favor you are doing for yourself is paying attention to your range estimates and energy consumption.
Dunno how much you are reading these forums, so in case you aren't, the "vampire drain" posters above have mentioned is the name for the concept of an EV losing energy, say overnight, due to other activities going on in the car. For example, a car might have an over-active monitoring system that is waking up every few seconds to watch all the other devices in the car. It takes energy to wake up that monitoring system, and then energy to gather all the info, etc. That's probably not the best example in that the energy required for monitoring shouldn't be that much. But if the monitoring were mistakenly happening say, 10 times a second instead of once a minute, then a bunch of extra energy will be consumed.
A more likely candidate for vampire drain, mentioned by another poster, is that your car's Battery Management System (BMS) could be triggering a lot of battery pack cooling activity if you are living in a particularly warm area. Over the course of two weeks, additional BMS cooling activity could consume a pretty good chunk of energy.
As another poster hypothesized, you might be making small trips. Small trips use higher amounts of energy per mile than longer trips. That's because when you first start out, the car has lots of additional stuff to do to get ready and also the battery pack may need to be warmed (or cooled). If you watch your energy consumption graph/info, you'll see that early on you might be using, say, 400 wH per mile. When your Model 3 is hitting its stride, say after 5 miles, consumption should drop to maybe 250 wH per mile. I drive an S and when I first start out might be getting around 450-500 wH/mile, then after it settles down it might go down to 330 wH per mile. Your range estimate will then go down much faster than your actual miles driven.
If you drive aggressively, you will also use more energy per mile than if you drive gently. Range estimate will then decline faster than actual miles driven.
You might want to spend a few minutes examining all of the controls and settings to see if there are any surprises.
Having said all that, I respectfully disagree with an earlier poster who said that, "Letting it sit, there’s a lot of vampire drain." While that was true with earlier software releases, at this point, most (nearly all?) people posting about Model 3, S and X are reporting small or zero overnight drains. UNLESS cabin overheat protection is kicking on, or you're leaving the climate controls running, or you've left the car in fierce direct sunlight or otherwise in a hot area so that the BMS repeatedly kicks in to cool the battery.
Generally speaking, many (most?) owners leave their cars plugged in at night, so they have a "full" (say, 80% full, you can set the charging maximum as you wish) battery every morning. If you do that, you won't have much if any range anxiety during your typical day, although you might still want to watch the energy consumption.
Finally, there are posters on this forum who consistently achieve range significantly in excess of what Tesla advertises for the EPA ratings. They typically drive gently and in some cases also "hypermile". I am not one of these people.
Best of luck to you.
Alan