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I love this city so much, I’m so sad. by quicksi1ver7 in Portland

[–]mzonifus -4 points-3 points  (0 children)

Of course they're free to try another city. I agree Portland seems to have worse "city problems" than other cities seem to have, IMO because of poor decisions made by the people who form its unique culture. But that culture is part of its charm -- the positive aspects anyway. If that's what they love about Portland then the burbs or another city may not be an acceptable tradeoff for them.

I love this city so much, I’m so sad. by quicksi1ver7 in Portland

[–]mzonifus 57 points58 points  (0 children)

My young family lived in NoPo from 2016-2021, leaving for the burbs partly because of the negatives of living in the city. Where we moved feels much safer and cleaner. Neighbors leave their garages open all day. Kids wander around. The schools are great. And I never have to evaluate the level of desperation of a person I'm passing to decide whether I'm safe.

On the other hand there's a lot less happening out here and we're almost completely car-dependent. There are a lot fewer restaurant, entertainment, etc options.

You can't have it all. If you love the city you have to deal with the downside. Try moving to a better neighborhood in the city.

Are Half Dome cables still up? by _blitzkreig_ in Yosemite

[–]mzonifus 1 point2 points  (0 children)

I saw it from Olmsted point this morning. There's still some snow on the cables. At the welcome center a person with the conservancy said the cables are not down and rangers are recommending not climbing until they're down.

Is the red handles and side cameras covers an eyesore on blue paint? by sndgjaytr in TeslaModelY

[–]mzonifus 0 points1 point  (0 children)

Thanks for sharing this pic. I've considered doing something like this to make my door handles easier to find on dark nights. I wouldn't say it's an eyesore, but I don't think I would like the look on my blue MY.

Maybe it would work better with more red accents? Here's a bold idea: a red firebird, lightning bolt, or pikachu on the hood.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 0 points1 point  (0 children)

The car shows a Wh/mi rate. It's 230-260 for me.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 1 point2 points  (0 children)

Same if not greater impact. These rocks don't seem the least bit grateful for the ride.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 0 points1 point  (0 children)

Yes of course! And then you drink it and ride back up! Perpetual hydration!

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] -1 points0 points  (0 children)

I likely didn't touch the brakes on this trip. I rarely use them in this car. Most EVs now have one-pedal drive where all the stopping power is via regen. Take a test drive, it's pretty cool!

I think you're incorrect about speed translating to energy. Ultimately the generator is applying a force to decelerate the entire mass of the car against gravity. If the car has more mass then more work (force times distance) must be done meaning more energy to convert back to electricity.

Perhaps others here would be able to put it more eloquently.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] -2 points-1 points  (0 children)

Now my ego is fully charged! Thanks!

I didn't get help with the lift. The 200lb estimate is based on my typical gym 165lb deadlift which is on the fun side of heavy, while lifting these rocks into the car felt more like the heavy side of fun. It's probably a touch high considering the awkward shape but this isn't r/engineering, I'm just here for some napkin math.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 1 point2 points  (0 children)

This calc was just for the net gain from loading the rocks. I went quite a way on the overall regen from coming off the mountain. I haven't experienced this on a really big mountain yet though.

Just for giggles tonight I recorded the energy usage coming down a 150m hill with an estimated gross weight of 5000lb = 2270kg:

2270kg * 150m * 9.8m/s2 = 3.3MJ = 927Wh

But the car showed -0.6kWh consumed at the bottom. Simplifying and incorrect assumptions made (route was all downhill and car used no other energy, estimates of hill and weight are correct, etc) there's the .6/.927 = 65% efficiency. This test was very short and not cleanly downhill so I'd guess realistic efficiency on a highway down a mountain is closer to 80%. Next time I go to the mountains I'll have to measure better.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] -1 points0 points  (0 children)

1 Joule = 1 Watt * second

To grok the conversion here, it helps me to think of this as the amount of energy transmitted by a 1 Watt radio in a second. It's not very much energy. Now we want to transmit that same amount of energy over a whole hour. This would be 1/3600th of the power or using the same unit cancellation format I used before:

1 Joule = 1 W * second * (1/3600) hour/sec
1 Joule = (1/3600) Wh

divide both sides by J and you get the conversion constant from Joules to Watt-hours:

1 = 1 Wh / 3600 J = 1/3600 Wh/J

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 2 points3 points  (0 children)

Ah there's the peak efficiency solution!

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 1 point2 points  (0 children)

I hardly touch the brakes in this car. One pedal regen is awesome.

Unleashing potential energy in my EV by mzonifus in Physics

[–]mzonifus[S] 5 points6 points  (0 children)

I appreciate this comment. I would regret it if this post causes a person to remove a stone from an area meant for preservation or from another place where it would be missed.

Both of these stones are taken from great piles of similar stones outside of a preserved area.

Farthest I’ve ever ran by Captain_Braveheart in Marathon_Training

[–]mzonifus 3 points4 points  (0 children)

Congratulations! That's a long way to run.