Recent content by Devin-M

Can I solve this as follows: In 2 charge cycles, 8.6kWh was invested heating the battery, at $0.45/kWh costing $3.87. This saved 30 minutes of charging time. If an Uber driver makes $30/hr while in motion, $15 extra dollars were earned in the time saved while charging. $15 > $3.87 therefore the...

The following morning it was 49F and the battery had 83 miles (18426Wh) remaining. The charging station was 5 minutes away. I planned to measure how long it took to add 100 miles (22200Wh) of range while only preconditioning the battery for the 5 minutes it took to reach the charging station...

I finally got a somewhat decent cold temperature measurement. The car is a 2022 standard range Tesla model 3. I started preconditioning the battery in the morning when the outside and car were approximately 29F. Battery state of charge 167mi remaining (37074Wh). After 1hr 53min of driving...

I took some measurements today. The temp was constant 55f. A full preconditioning took 3.3kWh. Then after 2 hours of driving and 61 miles traveled, maintaining the constant preconditioning took a further 1.3kWh. In the pictures below, the preconditioning energy use is shown in miles. These miles...

This graph supposedly shows 30F weather, initial 10% state of charge, temperature preconditioned (grey) vs not preconditioned (green: Source: https://insideevs.com/news/699912/supercharging-tesla-winter-preconditioned-vs-cold-battery-test/

PS… It isn’t necessary to fully charge the battery each time. As seen above, with the battery pre-warmed, two separate 15 minute charging sessions with driving in between provides more energy and range than a single 30 minute session. *EDIT: When I initially viewed this chart I thought it...

Problem: You’re an Uber driver with a Tesla Model 3. Today’s low: 30F, high: 65F. You want to reach a USD$ profit target in the least number of hours, but your choices could have added cost. Do you preheat the battery only when you are headed to the charging station (to increase the charging...

Sorry it’s taken me so long. I’m planning to run the numbers with a 5 solar mass black hole and a 1 solar mass black hole - in a conversation I had with Grok, it told me that the 5 solar mass BH could give 0.95c and the solar mass black hole could give 0.99c at a large distance in this scenario...

kinetic energy per Kg?

So in the formula in post 5, is y the lorentz factor, r the distance in meters from the center? Is M the mass of the black hole in kg? What is E? Energy in Joules?

I will try to work this out later when I have a chance, but on the basis of the photon sphere being smaller on small black hole, and therefore light has to orbit in a tighter radius, I would assume space is more curved at the photon sphere of a smaller black hole. It might take me a day or 2 to...

Would you get the same boost at the edge of the photon sphere with any black hole or is this specific to Sag A*?

And this: “ Oberth effect also can be used to understand the behavior of multi-stage rockets: the upper stage can generate much more usable kinetic energy than the total chemical energy of the propellants it carries.[2]”

Hmm, I thought some of the fuel getting more kinetic energy before being used might be helpful, since the wikipedia article for oberth effect says this: “ In terms of the energies involved, the Oberth effect is more effective at higher speeds because at high speed the propellant has significant...

I assume this is treating the burn as an instantaneous impulse. Would extending the burn over time result in higher speed? In this case, during the burn, a portion of the fuel would acquire more kinetic energy before being utilized.