Tesla

[Soup DeVille]

Yes, but identifying which component is the problem can frequently be a challenge, particularly if OBD aren't robust.  We constantly struggle with diagnostics on some of the motorized systems on some of our products because we didn't build in robust diagnostics.  Something stops working and the first question is "did the motor fail or the controller?"  So then it's a game of swap-tronics to figure out whether it's a bad motor or controller.  And to make matters worse, on one of our products we discovered that certain kinds of controller failures can fry the motor, so if somebody tries replacing the motor first when the controller is actually the thing that failed, that motor then is fried.  And since replacing the motor didn't work, they replace the controller and the thing still doesn't work because the new motor was just fried by the previous controller.  Then people spend a bunch of time trying to trouble-shoot cables...

That stuff used to be my specialty...

Anyways, a lot of that goes on on cars today as well, so I don't think it will be getting any worse, and in most cases I think it will be better.

[Morris Minor]

There was no Tesla style over-the-air update for the CR-V's center display. It was a pain in the arse dealer-executed update via a USB stick.

When I replace the Infiniti it will be with an EV.

[Raza]

There was no Tesla style over-the-air update for the CR-V's center display. It was a pain in the arse dealer-executed update via a USB stick.

When I replace the Infiniti it will be with an EV.

And when you drive it, you have to sing "Pow-pow Power Wheels!" the whole time. Those are the rules of driving EVs, I didn't make them, I just enforce them.

[Eye of the Tiger]

And when you drive it, you have to sing "Pow-pow Power Wheels!" the whole time. Those are the rules of driving EVs, I didn't make them, I just enforce them.

Now you're drivin' for real!!!

[Laconian]

Press the pedal extra hard for 9.6V //////TURBO POWER

[Eye of the Tiger]

Press the pedal extra hard for 9.6V //////TURBO POWER

Dood, I had that on my NiCad Tyco Turbo Hopper!

[Laconian]

Dood, I had that on my NiCad Tyco Turbo Hopper!

Why was it always 9.6?

https://www.youtube.com/watch?v=9o9ULKlJdUI

[Eye of the Tiger]

Why was it always 9.6?

https://www.youtube.com/watch?v=9o9ULKlJdUI

I don't know! I was 8 years old!

[giant_mtb]

Why was it always 9.6?

https://www.youtube.com/watch?v=9o9ULKlJdUI

I dunno. They make batteries in all kinds of voltages for r/c cars. Kinda like battery powered tools these days, the more V's, the better it must be!!

[Laconian]

High voltages means lower resistance and less heat, so it is kiiiind of true.

[Eye of the Tiger]

I loved that damn Turbo Hopper. That thing was my jam.

[Soup DeVille]

Why was it always 9.6?

https://www.youtube.com/watch?v=9o9ULKlJdUI

Ni-Cad cells produce 1.2 volts (or nominally so). 9.6 volts is 8 cells, which is a convenient shaped package using the most common AAA sized cells.

[Laconian]

This was my favorite RC car:
https://www.youtube.com/watch?v=hJOhfC7rz7U

[Eye of the Tiger]

This was my favorite RC car:
https://www.youtube.com/watch?v=hJOhfC7rz7U

Not a real car

[giant_mtb]

Tyco Rebound was pretty cool.

https://youtu.be/dfLZ1c15kh4

My favorite one was this one where the front axle was attached to the unit at the axle middle, like a helicopter blade.  The front axle had its own motor that would spin it like a helicopter rotor. So as you were driving, you could turn and hit the front axle spinny button, causing the whole car to tumble around and then it was shaped just right that it would mostly come back to all fours. Pretty sure it was a Tyco.

Edit: it was like this, but a more normal r/c size...https://www.amazon.com/dp/B004M63CNU/ref=cm_sw_r_apa_i_bBKWEb769QN2E

[r0tor]

I loved my black 9.6V Turbo Hopper... That was like the prized possession of my youth

[MX793]

High voltages means lower resistance and less heat, so it is kiiiind of true.

Higher voltage means less current for the same power.  Resistance is a property of the conductors and is generally constant.

[GoCougs]

Higher voltage means less current for the same power.  Resistance is a property of the conductors and is generally constant.

Kevin's exactly right - resistance increases with heat in a traditional (copper, aluminum, etc.) wire conductor, and it's a huge design consideration for electrical design (motors, cables, infrastructure, etc.).

[MX793]

Kevin's exactly right - resistance increases with heat in a traditional (copper, aluminum, etc.) wire conductor, and it's a huge design consideration for electrical design (motors, cables, infrastructure, etc.).

Please show me a wire catalog that rates the resistance of wire/cable as a function of the voltage carried.

Temperature rise in a conductor is not directly associated with the voltage applied.  Current (power) causes heating of a conductor (due to resistance in the conductor), and this causes some increase in resistance due to the material properties of the conductor.

[GoCougs]

Nice try .

[MX793]

Nice try .

So if I'm putting 10 watts down a 4 gage copper wire, there's more resistance in the wire at 12V than at 28V?

[Laconian]

It's good to be on the receiving end of some pedantry once in a while I give out entirely too much at work.

[Soup DeVille]

So if I'm putting 10 watts down a 4 gage copper wire, there's more resistance in the wire at 12V than at 28V?

Yes.

However, you've picked such a large gauge and such a small amount of power, I doubt it would be a measurable difference with any normal instruments.

[Soup DeVille]

Please show me a wire catalog that rates the resistance of wire/cable as a function of the voltage carried.

Temperature rise in a conductor is not directly associated with the voltage applied.  Current (power) causes heating of a conductor (due to resistance in the conductor), and this causes some increase in resistance due to the material properties of the conductor.

It'll show it as a function of temperature. As heat rises, resistance does by indirect proportion. For copper, for every 1 degree celsius in temperature increase, resistance increases by 0.39 percent.

For a given amount of power, increases in voltage produce a proportional decrease in amperage. The ampacity of a wire is directly based on the temperature rise created by the amperage. Most conductors are 30 degree rated, meaning that at their given rating, that amount of amps will increase the temperature in that conductor by 30 degrees

[MX793]

It'll show it as a function of temperature. As heat rises, resistance does by indirect proportion. For copper, for every 1 degree celsius in temperature increase, resistance increases by 0.39 percent.

For a given amount of power, increases in voltage produce a proportional decrease in amperage. The ampacity of a wire is directly based on the temperature rise created by the amperage. Most conductors are 30 degree rated, meaning that at their given rating, that amount of amps will increase the temperature in that conductor by 30 degrees

For a given power, higher voltage reduces the current, which means you have less heating in the wire and can use smaller gage wire.  I live this struggle with our system architects daily, because they like to use kilowatts of 28V power and then locate the power supplies as far as possible from the things that actually consume the power, so we have to carve out loads of space for heavy gage wire in raceways.

[AutobahnSHO]

So if I'm putting 10 watts down a 4 gage copper wire, there's more resistance in the wire at 12V than at 28V?

[Soup DeVille]

For a given power, higher voltage reduces the current, which means you have less heating in the wire and can use smaller gage wire.  I live this struggle with our system architects daily, because they like to use kilowatts of 28V power and then locate the power supplies as far as possible from the things that actually consume the power, so we have to carve out loads of space for heavy gage wire in raceways.

Yes, the lower the voltage is, (I do believe that's what i said?) the greater your loss over distance will be as well, because of the higher heat and therefore higher resistance.

It would make the most sense to mount your power supplies as close to the devices being powered as possible.

i have noticed though, a certain reluctance amongst IT people to work with line voltage; or to coordinate with people who do.

[GoCougs]

So if I'm putting 10 watts down a 4 gage copper wire, there's more resistance in the wire at 12V than at 28V?

This is not correct. All else is subordinate to it. :r0tor shrug:

Higher voltage means less current for the same power.  Resistance is a property of the conductors and is generally constant.

[MX793]

Yes, the lower the voltage is, (I do believe that's what i said?) the greater your loss over distance will be as well, because of the higher heat and therefore higher resistance.

It would make the most sense to mount your power supplies as close to the devices being powered as possible.

i have noticed though, a certain reluctance amongst IT people to work with line voltage; or to coordinate with people who do.

For us, it's EMI concerns most of the time.

[Soup DeVille]

For us, it's EMI concerns most of the time.

Unless you're not grounding things and/or running high voltage in the same trays as comms, that shouldn't be a concern.