BMW i3 Cost/Range Calculator Spreadsheet (mainly for REX owners)

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New member
Dec 7, 2023
If you're like me then a major reason for going electric is to reap the benefits of cheaper energy per mile. However, what about road trips or longer destinations? Is it cheaper to fill the car with gas on a long trip or charge up, especially as DC fast charging becomes more accessible.

I created this spreadsheet to help determine the cost savings and breakeven costs (in USA units, but easy to switch for those abroad). Basically, you enter in the average local price of gas in your area, as well as the kwh costs for home charging, paid level 2 charging, and DC fast charging, and this spreadsheet helps "convert" the costs to $/kwh equivalent, or $/gal equivalent. If you don't want to do the conversions here is the main points.
1. There is a very large cost savings if you are charging at home. At the time of this writing, I am paying approximately $1.79 per gallon equivalent (at $0.14 per kWh, 34 mpg on REX).
2. DC fast charging is not worth it unless you live somewhere with very high gas prices. (at $0.56 per kWh via electrify America you are paying approximately $7.00 per gallon equivalent).
3. If you take the time savings for charging into account, on a long trip your most effective option is to start the trip with 100% charge, run the battery down, run on the REX, and then charge on a free or cheap level 2 station at your destination before heading back. Avoid DC fast charging unless it is free or significantly below the equivalent gas cost.

I have attached the editable spreadsheet to this; I am curious the cost breaks for other i3 owners in other states.


A thing to note here. I am ONLY concerned about the economics of this. Let's please not make this thread about the potential environmental impact of gas versus electric travel, this has been discussed at length in these forums.


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