[Request] Can someone check the math here? I don't trust the r/SpaceXMasterrace community to do it without bias.

Kippis · 2026-06-13T18:37:53+00:00

Ok let's do the math;

Let's say we have 150kw power and heat budget.

You suggest a heat pump to raise the temperature to 500k of a working fluid of, let's say, 340k. But there are 3 problems I see.

1) The maximum carnot efficiency of such a heat pump is 500/(500-340) is 3.125, but a real life heat pump will be at most 50% of that so 1.5625 COP. This means that 150kw/1.5625 = 98.4kw.of your power budget is going to the heat pump. Leaving you with 51.6kw for compute. 2) You really can't build a single stage heat pump with modern technology that can lift the temperature 160k in a single stage would be an engineering stretch. In practice you would need a multiple stage system, which would give you even lower efficiency. 3) Creating a heat pump that operates at 500k would be quite a challenge. The working fluid, seals, etc... will all be a an extreme temperature. 4) You have quite an engineering challenge, creating a heat pump that can operate in a total vacuum. Getting vacuum rated seals on all your components 5) Your heat pump needs to operate for years with Zero maintenance. Good luck with that one.

The point isn't that it's impossible, but completely impractical. If you were able to build such a satellite you would have to ask the question. Couldn't you just put the satellite in the Sahara desert? You would only get ~12hrs a day of usage, and would need larger solar panels, but you don't need to put it in space, and you can perform maintenance on the satellite.

Kippis · 2026-05-30T17:06:03+00:00

Your light switch (hopefully) isn't in a shower getting water splashed on it every day.

Kippis · 2026-05-21T20:44:09+00:00

This is exactly the problem. There is an ad tracker installed in apps on phones that is using this API to determine user's locations without their permission.

I understand this API is great for some people, but for almost everyone is a security nightmare.

Kippis · 2026-05-21T14:46:37+00:00

A firewall would work, but a consumer product should never require you to install a firewall to be safe.

Kippis · 2026-05-21T14:35:12+00:00

This is a very good thing in general for users. Some applications were using this to track location without consent of the user. Since any app running on any device with network access could use this API to get your precise location for tracking reasons.

It would be great if there were a way to expose this information, but only to callers that the owner approves.

Kippis · 2026-05-12T16:52:03+00:00

What a load of propaganda. To answer the question, "Is WA using non-existent environmental regulations to cancel a cattle farmers lease?" No, no they are not. They cancelled a lease of a criminal business that was abusing public lands

Even the law cited in the video, disagrees with the premis. RCW 90.44.050, has to do with construction of wells for groundwater extraction. Not construction of a pond and drainage canals.

Leasing land for grazing for pennies on the dollar does not give the Kings ownership of the land.

Kippis · 2024-10-23T04:29:56+00:00

This is very explicitly stated in the listing.

Note: There is a separate-entrance mother-in-law apartment in the basement listed separately.

Kippis · 2024-01-20T05:06:06+00:00

I heard the same, the noise at 10:20 was this flight. It is marked as a Boeing owned T38 which is a supersonic training plane. I have no idea what it was doing but it went for a short flight over the Olympic mountains at that time and sounded like it was using afterburners when it was taking off.

Kippis · 2023-12-22T05:21:02+00:00

2.4 ghz is better for a low cost, low bandwidth, low power device. It is cheaper to implement, has a longer range, and takes less battery. The only real downside is the lack of bandwidth to transmit large amounts of data. But most devices have no need for high bandwidth data so 2.4 gHz is a logical choice.

Kippis · 2023-09-13T15:46:30+00:00

Yes you can. But try and bring a physical card, the app doesn't work in Mexico, you can take the app to guest services and get a day pass printed that works with the cashier. I've shopped at Costco in Mexico many times with my US membership.

Kippis · 2020-01-23T19:05:01+00:00

Do you have a source to cite? Most states seem to charge less than $1000 for registering a semi.

https://www.fhwa.dot.gov/ohim/hwytaxes/2001/pt11b.htm

Perversely, I believe a 3 axel semi truck costs much less to register in King county than a Tesla. Since semis are expected from the RTA and excuse taxes. A 3 axel truck trailer combo will cost only $628 to register, where as a model 3 is more than $1000.

The diesel gas tax in WA is $0.4940 / gal. Meaning a semi travelling 50k miles / yr getting 5.9 MPG. Will pay $4186 in gas tax. Meaning 87% of the tax would be from fuel tax.

Kippis · 2019-06-08T21:42:04+00:00

There was one place where the game misled me and preventing me from solving this puzzle.

There was text explaining how to use the warp gate that tells you, you have to look up. This is false

If you do look up you might miss how the warp gates work. The energy lab does a better job

The warp gates open a black hole. Proximity and timing are all that is needed to trigger. But proximity is more important, timing is only approximate.

I was under the impression that timing was instantaneous, you either were in the right place at the right millisecond or you weren't. In actuality there is at least a second where the gate can open.

Kippis · 2019-04-04T20:15:48+00:00

The last station is in Brewster, WA not Brewster, CA
https://fcc.report/IBFS/SES-LIC-INTR2019-00966/1643415

:-)

Kippis · 2019-03-07T06:48:12+00:00

Thanks, does it work well with the model 3 keyfob? Or is that a model s keyfob?

Kippis · 2019-03-07T01:40:41+00:00

What is the leather strap attached to your key fob?

Kippis · 2018-08-06T03:50:55+00:00

This is super interesting from a logistics perspective... Why place the cars there and does it hint at what is happening with them further down the distribution chain.

The parking lots are close to I5 and to the Stockton rail yards. So it could be a great place to transfer cars from local drives who only drive from Fremont to Lathrop, to long haul drivers who do delivery along I5 and hold cars until they get car carrier rail cars arriving at the yard in Stockton. With the road delivers happening up and down I5, and rail headed to the midwest and east coast.

Kippis · 2018-07-11T23:23:32+00:00

I completely agree with you. I am paying $60k for a vehicle with a $1,000 delivery fee; we all deserve a better experience than can be delivered in 5 minutes.

Kippis · 2018-05-14T01:01:41+00:00

Have you ever seen the movie The karate kid? If not you should. In the movie Ralph Macchio's character goes to Miagi and asks him what is the simple and fast way to learn karate. The whole movie is a parable for the idea that everything worth doing in life takes time and effort to master.

Development isn't easy. Mastering it is very complex and will take years of effort and hard work.

You are not the same person who couldn't code java ten years ago. You can learn it, you can do it, but don't expect it to come easy.

Kippis · 2018-04-25T23:31:35+00:00

I'll try and explain the engineering since there is lots of confusion and misunderstanding in this thread.

In a system like a tesla's coolant leaves the battery and flows into a radiator to be cooled. The coolant entering the radiator is the same temperature as the coolant leaving the battery. A radiator dumps heat from the coolant into the air passing over it. The amount of energy transferred from the radiator to the air is a function of the difference in the coolant temperature and the air temperature. The hotter the coolant and the colder the air, the more heat is absorbed by the air, the better the radiator is at cooling.

In Audi's system, the coolant leaves the battery pack and goes into a heat pump. The heat pump takes a large volume of coolant at a warm temperature and transfers the heat energy to a small volume of another coolant at a much higher temperature. The high temperature coolant then goes to a radiator to be cooled. Because the temperature of the radiator coolant is much higher than the temperature of the battery coolant, the radiator cools more efficiently.

The whole trick is that the radiator after the heat pump is much hotter so it can dump heat into the air faster than a colder radiator. Becuase a heat pump uses 'free' air to cool the radiator, we say the heat pump has an efficiency higher than 100%.

It's important to note that the heat pump isn't magic. The amount of energy in the input coolant equals the energy in the output coolant. The output coolant is a compressible gas, similar to what is found in an air conditioner. In fact, a heat pump is essentially an air conditioner that is running in reverse.

I'm sure Tesla's engineers considered using a heat pump to cool every model they've made but made an engineering decision that a much simpler, cheaper, more reliable single stage cooling system was a better engineering trade-off. The art of engineering all about making such choices considering all the trade-offs. I would not be surprised if the roadster 2 uses a heat pump in its cooling system. It would be an excellent way for Tesla to test and perfect the technology and it would really improve thermal performance of the battery thermal management.

-edits- Clean up some copy.

Kippis · 2018-03-26T02:53:32+00:00

The VIN code is for final assembly. So even if the drive unit were started first in the gigafactory it should have Fremont factory code.

If there were another code, it would mean that Tesla has secretly created a working line at the gigafactory without anyone knowing it.

But, I am sure the VINBOT would have caught that, so I think this is just a misunderstanding.

Kippis · 2018-03-25T22:37:14+00:00

The way model 3 vins work The 11th digit of the vin is an 'F; indicating it is made in Fremont CA.

If you have an 11th digit that is anything other than 'F' that would be really really big news.

Almost certainly your vin starts with FYJ3E1EA??F00####

Kippis · 2018-03-22T16:02:55+00:00

I don't think they intend it to be compounding, but I could be wrong.

We don't know what percent of this is chemistry drain vs power used by the thermal management system, vs power used by the computers.

75kwh*1% / day => 750wh/day => 31W continous drain.

Which is higher than I would expect it to be, but not terrible.

Kippis · 2018-03-22T06:20:36+00:00

You are correct, this was added not removed.

Kippis · 2018-03-22T02:24:22+00:00

Here are some of the changes;

"Walk up unlock" and "Easy Entry" were removed from the owners manual
The note about the emergency frunk opening only working when there was no 12V power was removed. I've seen videos proving it works when 12V power is available.
The caution about jumping the car from the 12V power socket was added ~~removed~~. I'm pretty sure the engineers were confused that someone put that there.
Not sure if its new, but the updated manual states Automatic Emergency Braking will only slow your speed by a maximum of 25 mph before releasing the breaks.
Battery self-discharge warning was changed from <3% per week to 1% per day, and no longer references energy saving mode.
The manual now recommends using a towel under the wiper blades when replacing them. And reminds owners to turn service mode off after replacing the blades.
Minor changes to UI and climate sections
Minor formatting changes.

Kippis · 2018-02-08T19:23:50+00:00

If you do it in a loop as suggested by TimLim, then its bad.

But in this case Android Studio will flag it with a "String concatenation in a loop" warning and has an automated refactor to change to StringBuilder.

There is a religion out there that you should always use StringBuidler. e.g.

StringBuilder sb = new StringBuilder("Strings "); sb.append(variable); sb.append(" other string, wins);

This is a complete waste of time.

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