After driving my Prius Prime for a month...

Discussion in 'Prime Main Forum (2017-Current)' started by Digloo2, Mar 27, 2018.

  1. Digloo2

    Digloo2 Active Member

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    It has been a month now since I got my Prius Prime that goes 25-30 miles on 100% battery power. I plug it in every night and recharge it. My driving habits are such that I hardly end up using the gas engine, and I've barely used 1/8th of a tank in the past 4 weeks!

    I just got my first utility bill from APS since getting the car, and it confirms my original estimates that my electricity usage roughly doubled, going from 6 kWh to 12 kWh per day, which is in line with the amount of electricity the battery in the Prime holds -- roughly 7 kWh. (Think gallons of water and it makes perfect sense.)
    Meanwhile, my bill went from about $40 to $65, which is about $25. Meaning it costs me less than $1/day to run this car on electricity.

    I've driven 700 miles in this time period (avg of 23 miles per day). Given that the car's regular gas engine is rated at 55 MPG and that gas costs about $2.25/gal, that would be about 13 gallons * $2.25 = $30 in gas for this time period if it has been 100% gas, or right about $1/day.

    (My work is 7 miles from my house, so I have no problem going to work and back, with a slight diversion, on 100% battery. The thing is, I have to go to N. Scottsdale for a class once or twice a week after work, which makes the gas engine kick in and run for 15-20 miles.)

    The car says my actual gas mileage has been 180 MPG, suggesting that I've used 3 gallons of gas (at 55MPG), which actually seems quite high -- 1/8th of a tank should be closer to 2 gals.

    So let's say I saved 11 gallons of gas at $2.25 = $24.75 while my increased electricity costs have been about $25.

    Which means that thus far, I'm pretty much breaking even cost-wise.

    My original estimate was that the cost of electricity would be about 1/2 that of gas, which was based on 800 miles driven per month and a higher percentage of longer trips that required the gas engine.

    As it turns out, I've driven 100 miles less than planned, and had more shorter trips that didn't need the gas engine at all. So as a percentage of miles driven, I'm getting twice as many miles on the battery vs. gas as I originally expected.

    And at the current rate I'm consuming gas, I won't need to refill my tank until around Thanksgiving. :)
    (My original estimate was that I'd go through a tank of gas about every 3 months, which illustrates how little I'm using the gas engine right now!)
     
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  2. priuscatprimeguy

    priuscatprimeguy Senior Member

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    hmmmmmm........ I pay my landlord $15.00/mo for the unlimited use of his electricity to charge my car so I'm paying 50 cents a day:eek:
     
  3. Digloo2

    Digloo2 Active Member

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    Lucky you! I pay my own utilities.
     
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  4. bwilson4web

    bwilson4web BMW i3 and Model 3

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    The fuel tank level indicators are not linear. Use MILES / MPG to get a more accurate gas usage. In your case, 700 miles / 180 MPG ~= 3.9 gallons.

    What I typically do is use the "B" tripmeter that is reset when filling the tank. I then use it to track the actual gas usage. Unfortunately I'm running a much higher ratio of EV to gas and mine is pegged at 199.9 MPG. The "A" tripmeter is used for shorter segments.

    One caution, there is a poorly documented 'lifetime' distance and MPG that can be accessed using the ECO App. BUT be careful and don't hit UPDATE:
    Prius Prime Plus in my hands | Page 26 | PriusChat

    Now that the 'newness' is starting to wear off and the car has passed the 'documented' break-in period, consider topping off the tank and resetting the "B" tripmeter. This will give you a more accurate report of miles and MPG.

    Since you live in Arizona and only have one plugin, I would recommend one of the 20A, 120/240VAC, chargers. Our Prius Prime only takes 16A at full charge rate. If you have a dryer outlet near the parking place, you can cut the charging time in half and use the key fob to activate conditioning when hot weather returns. The 12A 120VAC charger that comes with the car is a little weak.

    Bob Wilson
     
    #4 bwilson4web, Mar 28, 2018
    Last edited: Mar 28, 2018
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  5. Digloo2

    Digloo2 Active Member

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    Yes, I use A for tracking daily trips, and I reset B when I fill the tank. But as I said, after a month, there has been very little gas usage.

    Yes, I'm working on an extension to the dryer plug, which is only about 5' from the driveway wall. (I'm looking for a switch to put in the line.) But given that there doesn't seem to be much savings with the 100% battery mode, I'm wary of investing much in it.

    Actually, people have mentioned a lot about the heat issues in the forum here. The Phoenix area is quite spread out, and we have several different "microclimates" that nobody talks about. The temps that are reported are at the airport, which lies in an area that gets a bit of a breeze during the day, so it's a little cooler than some other areas. Many days the reported "high" has been 116 when I've seen it over 120, sometimes as high as 123. The highest I've seen it in the past couple of years was 126, but I don't recall hearing that we ever "officially" hit 120 in quite a while. (I've see it hit 120+ about a half dozen times every summer.)

    I never had a problem with my Prius V, but then I didn't have to plug it in.

    I'm wondering if it might be best to not use the "traction battery" (why is it called that, anyway?) when the temps go over 105 or so? (That's usually early June thru mid-to-late Sept.)

    Also, I'm thinking that I don't need an extra $30/mo on my electric bill in the summer when it's not actually saving me anything over gas costs.

    I only charge it at home in the (covered) driveway in the evening. And there's often a wind here that blows through the driveway like it's a wind tunnel. (It's open on both ends.)
     
  6. bwilson4web

    bwilson4web BMW i3 and Model 3

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    It dates back to the earliest Prius and serves the purpose of avoiding confusion with the 12V battery. We call it 'traction' because it has the ability to move the car with the engine is off.

    Bob Wilson
     
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  7. jerrymildred

    jerrymildred Senior Member

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    Going back even farther, I think it may have the same origins as "traction engine," which fits nicely with your explanation. (y)
    • "The name derives from the Latin tractus, meaning 'drawn', since the prime function of any traction engine is to draw a load behind it."
    From:
    Traction engine - Wikipedia
     
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