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Comment: Re:Help me out here a little... (Score 1) 494

by dgatwood (#49517525) Attached to: Utilities Battle Homeowners Over Solar Power

Let's take water as our analogy. Water flows to meet demand in the form of open taps. But very few of those taps are strictly regulating, and the outflow is a function of how far the tap is opened and the pressure in the system. Put more water into the mains and the pressure goes up, therefore more water is delivered at the tap. If your house has pressure regulating valves, you won't see this, but the pressure is then further increased at someone else's house.

That analogy doesn't really work very well, for two reasons:

1. Water pressure is more closely equivalent to voltage, not amperage. Adding more solar panels increases the amperage, not the voltage.

2. Most electrical equipment is strictly regulating (ignoring inrush). Resistive loads consume a consistent amount of current regardless of how much current is available. That's why it doesn't matter whether you power a 12V bulb with eight AA batteries or a 12V car battery. The latter can provide a lot more current, but the bulb still draws just as much current as it needs.

I think a better analogy is to think of the voltage as the height of a water tower, and the amperage as its diameter. If you have a ten-foot-diameter tower that forms a 50-foot column of water, the pressure is proportional to the 50-foot height of the water column. An overheating condition would be equivalent to the pipe breaking because someone is sucking water out of the pipe faster than the pipe can pass it.

If you expand the tower to be thirty feet in diameter, the column is still about 50 feet high, so the pressure is about the same (assuming the sides of the tank are vertical and the bottom is flat). However, doing so allows you to add more pipes and/or larger pipes out the bottom so you can provide water to more houses without drawing down the reservoir too quickly (and thus causing... what, a vacuum in the water tower? This is where the analogy starts to break down unless you're talking about a battery).

Comment: Re:Probably best (Score 1) 389

by Grishnakh (#49516047) Attached to: Automakers To Gearheads: Stop Repairing Cars

The problem is the modern, computer on wheels vehicles where everything is integrated into a network and your car refuses to start when it notices the gas cap hasn't been screwed in completely.

Hmm, I just ran into this problem on my (highly-networked) 2005 Volvo, where my wife apparently didn't screw the gas cap on tight enough and it came off while driving. It ran just fine, it just lit up the check-engine light. I plugged in my handy little OBDII scan tool, it showed a code about a large EVAP leak, I checked the gas cap and found it sitting inside the little gas cap compartment, cleared the code with my scantool and everything's fine.

OBDII is a wonderful thing. I do wish they had made the standard a little better, with fewer ways for automakers to insert proprietary BS in there, but it's great otherwise. You just couldn't do this stuff on older cars; with OBDI, every make had a different manufacturer-specific scan tool.

Comment: Re:You no longer own a car (Score 1) 389

by Grishnakh (#49515997) Attached to: Automakers To Gearheads: Stop Repairing Cars

3: Still another vehicle manufacturer, from overseas only warrants their vehicles to run B5. Well, guess what... you may encounter random gas stations and states which mandate all the way to B20. Fill that vehicle up with that type of diesel fuel, and the ECM will flag the warranty as voided, throw a check engine light, then go into limp-home mode (max speed 20 mph) until the fuel is drained and the dealer plugs in a device. The dealer might just demand all injectors and the high pressure fuel pump be replaced just for giggles until he resets the ECM as well.

Um, I don't see the problem with this one. Manufacturers have every right to require you to use a certain type of fuel; if you put diesel in your gasoline car, do you think the dealership is going to fix that mess for free? Yeah, it sucks that the grades of diesel available in the US are shit; in Europe, they use better diesel, and their cars are designed for it. That's a good reason not to buy a diesel car in America.

The other things are indeed BS, especially the battery thing. One requirement of any automotive electronic module is that it has protection on the power bus, to protect against overvoltage and even installing the battery backwards, and also something called a "load dump", where some moron disconnects the battery while the engine is running. This circuit protection has been standard for decades. Generally, you can satisfy these requirements with a rectifier diode on the input and a TVS (transient voltage suppressor) diode).

Comment: Re:You no longer own a car (Score 1) 389

by Grishnakh (#49515945) Attached to: Automakers To Gearheads: Stop Repairing Cars

The automakers have tried this before. The US federal government had to step in and fix it, with the Magnusson-Moss Warranty Act, which makes it illegal for automakers to require you to use their dealerships or parts, or to deny your warranty claims based on this, unless they can prove the non-OEM part caused the problem or they give you the parts for free. (This also includes fluids; some automakers tried to insist that not using their $$$ manufacturer-branded oil or coolant was grounds for denying a warranty claim.)

Thanks to the DMCA, they're trying this shit all over again. Thanks a lot, Clinton.

Comment: Re:You no longer own a car (Score 1) 389

by Grishnakh (#49515919) Attached to: Automakers To Gearheads: Stop Repairing Cars

it is not obvious to me that there's been significant improvement in gas engines over the past 20 or 30 years. I don't see a lot of similarly-sized new cars that do better than - or even as good as - my old beater.

It's not obvious to you because you aren't paying attention and looking at all the variables. New cars are different from early 90s cars in two big ways:

1) weight. 1a) crashworthiness: a new car will let you walk away from horrific crashes which your '93 POS will kill you. That alone should get you to dump that old heap. However, that crashworthiness comes at a price: cars are heavier than they used to be, usually by at least 500 pounds. Those 80s econoboxes were really small and light; you can't get anything that light any more. 1b) soundproofness: new cars are much quieter inside than your '93 POS. You're probably deaf now because all the interior noise in that thing. However, again this comes at a cost: the soundproofing adds weight. It used to be that only expensive luxury cars like Mercedes had this stuff, but now even $25k regular cars are super-quiet inside.

2) horsepower. New cars have a LOT more horsepower than your old '93 POS. Even "economy" cars are fast now. Back in the 80s, it was normal for an economy sedan to have 90HP and take 15 seconds to get to 60mph. Not any more; even "economy" cars now have sub-10s 0-60 times, and "regular" sedans can do it in 7-8s, which used to be sports car territory in the 80s-90s. No one wants slow cars any more, and in fact they can be considered dangerous since they can't merge properly. But again, this comes at a price: fuel economy.

New cars with GDI engines have truly impressive fuel-economy numbers these days, being able to push 3200-pound cars around with 200+ HP while still getting 37mpg.

Comment: Dealerships HAVE become more cost competitive (Score 2) 389

by damn_registrars (#49515869) Attached to: Automakers To Gearheads: Stop Repairing Cars
I have found that in recent (say 10 or so) years dealerships have become a lot more cost competitive; at least for some types of repairs and maintenance procedures. One example I have noticed is with oil changes. My car uses synthetic oil, and a lot of it. I priced out what it would cost me to change the oil myself if I bought the appropriate oil at the local parts store, and the filter. I then called the dealership and their cost to me for the same was only $5 more. If I had done it myself I would have spent $5 running the used oil somewhere for disposal, and likely had to spend time afterwards cleaning up part of my garage. it was well worth the $5 to let them do it.

I have found other similar situations with brake jobs (I would normally do these myself but in situations involving stuck calipers or parking brake pads that won't release, I call and price it out at the dealership and local brake shops).

Now, I haven't encountered the need for a really large repair yet. I don't know if this scales or not. But it does suggest that the dealerships are aware of consumers pricing out these things and have brought their charges down in response.

Comment: Re: And once this school fails to get women intere (Score 1) 596

Exactly right.

I will admit that MGM isn't as bad as FGM (plus, there's different degrees of FGM), but trying to say MGM is a good idea because of this is like saying chopping off your forefinger isn't as bad as chopping off your whole hand, so let's chop babies' forefingers off.

However, I will point out that it isn't "society" which thinks it's OK to mutilate young boys, it's American society (and Jewish culture too). The rest of western culture doesn't share America's puritanical sensibilities.

Remember, the entire reason America is so big on circumcision is because Dr. Kellogg in the Victorian Era pushed it as a way to discourage young boys from masturbating.

Comment: Re:My B.S. Detector is Going Off (Score 2) 68

by Bruce Perens (#49515639) Attached to: Old Marconi Patent Inspires Tiny New Gigahertz Antenna

If the end of the coil that is hanging is grounded (earthed), it becomes an autotransformer. As it's shown, it's a variable inductor and the disconnected end is irrelevant and has no meaningful physical effect at the frequency a spark transmitter could have reached.

This comment seems to get closer to what they actually mean in their scientific paper. But the article about it is garble and the paper might suffer from second-language issues, and a lack of familiarity with the terms used in RF engineering.

Comment: Re:You no longer own a car (Score 2) 389

by Grishnakh (#49515629) Attached to: Automakers To Gearheads: Stop Repairing Cars

Um, I don't think they're using those in any modern headlights yet, except maybe for a handful of high-end luxury models perhaps. They still aren't installing xenon headlights on "normal" cars yet, only on the higher-end (30k+) models. They've come down some, but the $15-25k segment still uses old-fashioned halogens.

And xenon headlights are pretty easy and cheap to fix, at least if it's just the bulb; the bulbs are readily replaceable, no different than the halogens.

"I've seen it. It's rubbish." -- Marvin the Paranoid Android