Mathematicians needed! PiP Charge cost vs Gas

You can apply statistics incorrectly to anything, just as you can trumpet some facts while ignoring others, or deduce a conclusion starting from a silly premise.

 

I really did include enough caveats. Net-metering implies same price going in as out, Non-TOU implies no difference in price depending on time.

If one is on a feed-in-tariff plan, and a time of use plan, then one is golden. Not the norm in the US, by any means.

 

another duplicate. sorry.

 

It would be my request that you not do that, especially by spouting dogma that is just false. Quite frankly, if they can't justify it with correct math, they shouldn't choose one. Correct math in this case includes all the externalities that are usually ignored, such as the cost of wars of oil acquisition, pollution, and climate change.

"Oh, yeah? Not to me." -- Secretary of Defense, _Buckaroo Banzai_

One can only prove true things with statistics, to someone conversant with statistics.

 

I was commenting on the discussion started from your post:

I did 8 EV-only trips each starting with 85% SOC and carefully recharging after the trip 80.9 miles for 18.98 kWh gives 4.26 miles/kWh. That would be 143 mpg-e without including the gas that the EPA uses in the calculation. If you include the gas per the EPA it calculates as 112 mpg-e. The trips ranged from 6 to 13 miles to/from a variety of locations.​

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From that post, you did not use any gas for 80.9 miles. So why add gas?

EPA test has City and Highway cycles. PiP completed the city cycle in full electric. However, it used 0.2 gallon of gas in the highway cycle. That's why the combined 95 MPGe figure has 0.2 gallon in it.

If your trips are only "city" driving condition (ICE unused), there is no need to add gas.

As you said, sometimes you'll use gas. If that happens, then add the amount of gas used. The EV Ratio screen made it easy to track the kWh and gallon consumed.

 

Except how many kwh per mile varies a lot...especially based on speed and driving style. I regularly measure it as much closer to 0.2 kwh per mile (actually even lower).

Mike

 

Just for comparison purposes I gave both values. If I only did the without-gas someone would probably have said that isn't the same as the EPA. When I did add gas someone said "no need to add gas". Makes for a lot of postings

 

Do we need to say YMMV on *every* post? Which I did, by the way.

 

No biggie...but with kwh (especially since it is probably an unfamiliar unit for most drivers) the numbers can be quite variable, much more so than mpg. Everyone (who cares much) knows the Prius gets about 50 mpg. Yes, maybe some drivers can get 55 or 60 mpg...and some get as low as 40-45 mpg. So, 50 mpg plus or minus 10 is only about plus or minus 20%.
You gave an "about" number of 300 watt-hours. I measure about 180 watt-hours over a week's time almost every week. That is 40% different. Some maybe it should be YMMVAL. (YMMV a lot)

Mike

 

So does that mean it takes 3.6 kWh to get a full charge?

 

approximately.

 

Since this thread has been restarted, can I point out that a quick 'n' dirty calculation for those who buy their fuel in litres, assuming an average (which is about right for me) of 12-13 miles on a charge over the year, is that you compare the cost of three units of electricity with a litre of fuel. Since I currently mostly charge at night on an off-peak tariff, that' s about 24p v £1.30.

 

If you do the math on car ownership, and took it to heart, you'd likely be riding the bus.

 

Counting the costs of my home charging station and extra cables I bought to be able to charge on public charging stations in EU, I am not sure plug-in is that cheaper any more...

 

Not me. I gave up my MD temp tag once the old tag got transfer. I am 100% VA now - NOVA in Gainesville area.

 

My estimated cost per mile on electric vs. gas is about 1/2 the cost of that of gas when running in EV during summer months. This is in Northern VA where I am paying about $3.15 per gallon. I inflated the cost of electricity due to tax and increase in cost as usage increases. My current estimated MPGe is ~74 based on the display.

 

I'm considering a 6kW solar panel system because I'm sick of paying $.31/kWh, stuck in SCE's highest tier. That's now approaching the same cost per mile as gasoline.

But I'm going to make sure that when I get a Tesla ), I can charge an 85kWh battery plus the PiP and still stay in the moderate tiers under $.20.

 

I experienced nothing close to those kWh / mile
In warmer temps I was 18 cents - in the two coldest months of a New England winter I was at 25 cents.
After 12 mos I ended up at 20 cents or $1.80 gas

 

PV is wonderful, but efficiency and conservation is much cheaper.