Voice of the DBA

Category: Blog

  • Tesla Power Use in Summer and Winter

    This is part of a series that covers my experience with a Tesla Model Y.

    When I look at my top destinations in the Tesla, I find that home is the top one (327) and my gym is second (102). That seems about right as I go to the gym 3-4 days a week and usually run some other errand then.

    2022-06-07 08_51_39-Drive Stats - Grafana — Mozilla Firefox

    When we got the Tesla and started to drive a bit, I found myself enamored with the Energy usage screen. It tracks the last 30 miles (configurable) and gives you a range estimate. Here is a typical screen for me:

    20210922_161212

    This shows the energy usage as I drive, with the most recent mile on the right and the oldest (30th) on the left. I see the amount of watt hours used at that time and then an average. There’s also a solid horizontal line for the rated range.

    For this 30 miles, I averaged 218Wh/mile, which is pretty good. You can see there are some high spikes in the 500Wh/mi range and some low ones. The green areas are where I actually recovered some energy back. This was at the lowest point leaving my house and heading West to Parker, CO, which is about 800 feet lower in elevation. I actually am generating power with the regenerative braking thanks to gravity.

    The Gym Run

    I go to the gym regularly, often 3-4 times a week. It’s an easy drive, and I’ve played the energy video game for years, trying to use the minimum amount of gas (Prius) or power (Tesla) on my trip there. I found this to be fun, and I’ve beaten my high (or low) score a few times.

    With the Tesla, it’s been an interesting metric to see how much power I used in the summer and winter. I grabbed a few screen shots in the fall when the weather was warm and then again in the winter. Here’s what I learned.

    Summer(ish)

    Here’s a summer graph. This trip was a 72F day, so not too summer-ish, but warm. A pleasant day. The drive stats are:

    • 11.8mi
    • ~2% battery used downhill
    • 21 minutes
    • 133 Wh/mi downhill
    • 1.6kWh

    The return home is as little different as I went to the grocery, but I had:

    • 9.8mi
    • ~4% battery used
    • 342 Wh/mi
    • 3.3kWh

    This is reflected in my graph for the downhill. The arrow is about where I start from home and the end is the gym. Lots of downhill, though not all. I was trying to be careful here and managed to get my 30mi average down to 184Wh/mi.

    20210922_142615

    This was pretty good to me, though admittedly I don’t have any point of reference as this is my first electric car. In terms of cost, this still is about US$0.69 for the drive. As a point of comparison, the X5 would cost about a gallon of gas. Around US$3.20 back then. The Prius would have been US$1.47.

    Winter

    A similar trip, slightly longer, so I must have varied the route a bit, but I see this:

    • 12.0mi
    • ~3% battery
    • 228Wh/mi
    • 2.7kWh
    • 33F

    The return:

    • 10.2mi
    • ~5% battery
    • 360Wh/mi
    • 3.7kWh
    • 28F

    The temperature dropped here, and as you might have guessed, I was using the seat and car heaters.

    What is interesting here is the downhill show 133Wh/mi in summer and 2.7 in winter, a significant change. The uphill has less of a difference ( 3.3 v 3.7kWh). Gravity is a bigger issue, I’m guessing. Maybe some battery conditioning on the downhill as well, but that’s still a factor.

    The cost in winter is more like US$0.90. While the BMW is still in the 20-21 range in winter, the Prius dropped from 47-48mpg to 42mpg, so it also showed a bigger battery effect in cold weather.

    Conclusions

    I don’t quite know what to make of this, other than expect range to shorten in the winter and plan for more charging. In general, since I mostly charge at home and my daily trips never get close to the range limit, this doesn’t change anything for me. We will use more power in winter, but since we don’t have time of day (or year) cost changes, and we have solar power to somewhat stabilize the cost of power, I don’t worry about this affecting my life.

    We have learned to cut off Sentry mode and also to charge a little more in cold weather if the car is sitting outside and unplugged. It’s not a big deal, but it is something to think about if you have an electric car in a cold climate. A little more forward thinking is needed in this paradigm.

  • Daily Coping 17 Jun 2022

    I started to add a daily coping tip to the SQLServerCentral newsletter and to the Community Circle, which is helping me deal with the issues in the world. I’m adding my responses for each day here. All my coping tips are under this tag.

    Today’s tip is to spend a few minutes looking at a piece of art and think about what you enjoy about it.

    I haven’t ever been a bit art fan. However, I saw an ad for the Van Gogh Experience in 2021 and mentioned that it looked interesting to my wife. She bought tickets and last fall we went. It was cool, and hard to describe, but essentially a movie version of many pieces being drawn on walls and evolving.

    I really enjoyed it, and since then, I’ve kept a Van Gogh painting as a background on my desktop, rotating with a family photo or two and my coping calendar.

    Right now, I have this piece on my desktop:

    tlA9gj4-van-gogh-desktop-wallpaper

    This reminds me of Europe, in old time, when we have life going on. People working, a horse and carriage on a daily journey of work, perhaps going to load up the work from people washing clothes in the river.

    Perhaps because I do most of the laundry, I’m glad I don’t clean clothes in a river, but at the same time, there is a level of pleasure from accomplishing something manual like this.

    I’m also amazed by the brightness of colors and how they paint a picture, despite being very different in similar places. The bricks of the bridge having yellowa, greens, oranges, even a bit of blue. It’s like a vivid reminder of the richness of life. I love the way m imagination creates the details that are blurry in this style of painting. I think I see something else in the water each time I look. Sometimes it’s the plants, sometimes I see fish. Sometimes I think there are more plants than others. Sometimes I can imagine the oil slicks or pollution I see in many rivers on my travels because of boat engines.

    I find myself enjoying taking a moment on these paintings, thinking how Van Gogh’s life might be different and similar to mine.

  • VS Live Slides and Code

    Thanks to everyone that came to my talk at VS Live today.

    I’ve uploaded the slides to the blog. Here are the two decks:

    Code for the CI Talk is on my Github. You can git clone from here: https://github.com/way0utwest/usingcitopreventdbproblems.git

    The code is structured as:

    • 0 files are setup, numbered 04, 06, 08, and 10. These create objects, add the tsqlt framework and load some data.
    • 20_Standards.sql – Standards based tests
    • 30_logicerrors.sql – The logical CASE statement test
    • 40_tsqlt_sqlinjection – Catching SQL Injection issues with EXEC()
    • 50_preent_alter – I didn’t demo, but how to look for code you don’t want developers to run.
    • 61, 62 63 – Older separation of concerns testing for procs/functions. I haven’t tested this lately, but it should work.

    If you have questions, let me know.

  • Daily Coping 16 Jun 2022

    I started to add a daily coping tip to the SQLServerCentral newsletter and to the Community Circle, which is helping me deal with the issues in the world. I’m adding my responses for each day here. All my coping tips are under this tag.

    Today’s tip is to listen to a favorite piece of music from the past.

    I woke up the other day and saw a new album from BTS. I put it on and listened. Not that I’m a big BTS fan, but I haven’t heard much of their music, so I just put it on in the background as I worked.

    Then I ran across this tip.

    For some reason, I first thought about Changes, but 2Pac. It’s a song of life from the 90s, from the perspective of a young black man in the Baltimore/DC area. For some reason I can appreciate the struggle of growing up like this, even though my life has been nowhere near as hard as it is for many people.

    However, I believe in changes and becoming better.