Quote:
Originally Posted by bagekko
Few weeks ago I was curious what the real cost of running our i3 and was surprised by the results. Then this week I realized the MPGe rating is nonsense and nothing close to real world MPG. So I ran some numbers and EV's dont provide as much savings as I thought and those Tesla calcs are total bullsh!t.
The problem is any EV savings calcs just use the cost of the kw not all the other related costs on your energy bill. On mine the kw costs about 12-13 cents but after supply charges and taxes the total cost per kw is actually 25 cents.
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Thanks for taking the time to run the comparison, but there are a couple of critical discrepancies in your table.
First of all, energy cost varies by location and by your chosen electricity plan (there is more than one to choose from!). There are variable and fixed rate plans, those with fixed usage cost per KWH, and those with variable cost on various thresholds of consumption.
To be specific, my cost per KWH is $0.006982 for the first 390 KWH (yes, less than a penny), then $0.102618 for the 1,100 KWH. The delivery charge is $0.035927 per KWH.
The overall average for the last NJ JCP&L bill cycle was $0.102618 for energy + $0.035927 for delivery == $0.138545 overall, lets call it $0.14 per KWH.
I'm not disputing your observation, just saying that with some shopping, you can probably do better!
Quote:
Originally Posted by bagekko
I dont know if the whole battery on the Tesla is usable, so I used the total battery on the i3 in the calc versus the actual usable 30kw, if you change it to 30kw it comes out to the same 40mpg as the Model 3.
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Neither i3 nor Model 3 (nor any other EV) use 100% of their battery.
i3 uses 27.2 or 33 KWH battery, or 82% of listed.
There is no explicit ratio listed by Tesla, so I would just assume something similar.
BTW, premium gas has not been below $3.xx / gallon for a while on the East coast, above $4.xx on the West coast.
https://gasprices.aaa.com/
Quote:
Originally Posted by bagekko
Now if you change the total electricity cost to $0.35 as is found in many major high cost cities, the i3 or Model 3 will not really save you any money over 27 mpg gas equivalent!
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There is something wrong with your math (implied EV MPG makes no sense).
I've corrected a few other data inputs in your analysis (see table below), but the bottom line is this: I drive ~300 miles/week in a car.
TM3 would cost me almost 1 full battery charge (325 mile range), or $7.95. My BMW M3 costs me 16 gallons of premium, or $48.80.
That's 6x difference.
Annually, that's the difference between $2,538 (M3) vs. $413 (TM3).
To break even between the two, I would need an ICE car with 6x mileage of my M3's daily average mileage of ~19 mpg (more on highway, less on track).
That would be a 114 mpg ICE car.
I haven't heard of any that approach that.
a
P.S.: Updated table, formatting likely to be butchered:
_______________BMW i3_____Tesla Model 3 LR_____BMW M3_____$ ICE/EV
Battery - KW__________33____________75 -
% usable_____________82%__________82%
Battery usable, KW_____27.06__________61.50
Electricity Cost per KW__$0.14__________$0.14
Battery Charge Cost____$3.79__________$8.61
Range_______________114____________325
M3 daily MPG___________________________________18.75
Per gallon cost, premium__________________________$3.05
Cost Per Mile__________$0.0332_____$0.0265________$0.16____ _6.14
Weekly driving_____300_____300_____300
Weekly:____________________$7.95_____$48.80
Annually:___________________$413_____$2,538_____6. 14