Slashdot Mirror
42-Volt Autos
brianlmoon writes "Car Audio Electronics Magazine has a story about the auto industry switching to 36/42-Volt systems starting in 2004 and being completely switched by 2020. The demand for luxuries in cars has grown to where 12/14-Volts is just simply not enough. The automotive sound enthusiasts are going to benefit greatly as amplification will be much easier and cleaner with 3 times the voltage availble. Mobile computing will also benefit: "One of the real benefits of jumping to 42-volt systems, especially for hybrid vehicles, is the ability of the vehicle to offer regular 110-volt electrical outlets". It seems cars will have dual systems for a while for legacy equipment."
Can't wait to see what these new batteries are going to cost...
Only the State obtains its revenue by coercion. - Murray Rothbard
Does this mean if my new car has a 42v system and the car battery dies and leaves me stranded out in BFE, I have to wait for another 42v car to come by before I can get a jump? That would suck.
Sure it mentions Hybrids in there but we all know that it is the "luxury" cars driving these changes, larger power-supplies will require more power to charge, which in turn requires more fuel.
So excuse me if I don't "welcome" this so someone can have an even louder stereo while pumping even more chemicals into the atmosphere. So we can have 110v power supplies so... so what ? So a "busy exec" can have an even large mobile office ? So Ted and Rhona in the back can have a Playstation 2 each ?
I would say that goverments should be introducing regulations to reduce fuel emissions... but somehow in the country where this will be plonked into Canyenero style SUVs I doubt that the Oil President will concern himself with more fuel being used.
An Eye for an Eye will make the whole world blind - Gandhi
What's "regular" about 110 Volts?
If 36V is better than 12V, 230V surely must be better than 110.
This will be really nice when I find myself needing a jump... now I'll need three or four 12v batteries daisy chained to do a jumpstart.
Not to mention the other downsides (easier to get shocked from 36+ volts, easier for the electrical system to fry itself in a flood situation, etc).
Is it just me, or is the automotive industry quickly moving to purely disposable/recycleable cars? When I look at a 2003 model car, I have a hard time picturing it still running and still together in 15 years. Really makes me wonder what a 2010 model car will be like.
I was always under the impression that clean amplification had to do with a clean, stable power source, not high voltage. Also, why does voltage matter for more power-hungry electronics? Amperage is the measure of load. Homes have exponentially increased power comsumption, yet the answer has been higer amperage wiring, not extensive high-voltage circuits. Finally, how does 42V DC convert much easier to 120V AC? Don't you still have to use an inverter?
On of the great things about 12V car systems - that (except for the coils and spark circut)is almost impossible to kill yourself electrically when you tinker with your car.
42 vols can kill you though - it can easily jump across wet skin.
Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.
Saw this one coming when we bought a new car for my wife and it had a water cooled alternator!
Her car has more luxuries and gizmos than any of our previous cars: Navagation System, Universal Garage Door Opener, 11-speaker sound system w/ DSP, CD Changer, Rear hatch auto-closer (close hatch the last inch), 8 airbags, 16-way power seats, rear wiper arm, etc.. bla.. bla.. bla... and so on..
I talked to my mechanic about it and they already knew the 42-volt systems were coming. They said 42-volts was chosen to avoid amperages that would harm humans while providing enough capacity for all the stuff being piled onto the latest models.
It's a small miracle that the battery drain if the car isn't driven every day....
The only problem I see with this is that a 12V system cannot self sustain an arc while a 42V system easily can. If a 42V car gets in an accident, the higher voltage system may present a problem for emergency workers as they could receive a nasty electric shock while trying to open the car up to get the passengers out.
The new batteries shouldn't cost 3x as much either. Yes, it will have 3x as many cells, but the cells could be 1/3rd the size, which could give the battery the same capacity as one of today. Of course, they do expect higher electricity demands in the future, so batteries will probably get larger (and would have to do so even if we stayed with 12v) so the size and price of batteries will probably increase somewhat.
As far as providing 110V AC circuits, they can do this pretty easily and cheaply now, if they wish. 36V systems won't make this that much easier. (It will make it easier to provide higher capacity 110v circuits, however. A hair dryer draws 1500 watts, which is 10 amps at 110 V or 125 amps at 12 volts. 10 amps is a lot, and 125 amps is massive. Assuming a 100% efficient inverter (which isn't possible), a 36v system could would only need 42 amps to power that hair dryer. Still a lot, but the wires needed to power the inverter would be a lot smaller.
(Of course, 42 amps is still a lot, and so it's unlikely that many cars will have an inverter capable of producing 1500 watts of power. But 500 seems likely.)
And no, I wouldn't expect this to affect the 1000+ watt stereos out there much. A 36v system would make wiring up one of these stereos simpler, because you could use smaller wires, but other than that it would be the same. The stereo could have some smaller wires internally as well, so in theory it might be a bit smaller and cheaper, but I'd expect that effect to be minimal.
Higher fuel economy can be achieved through several means on a 42V system:
- An integrated starter/generator built into the engine's flywheel, replacing both the heavy and inefficient alternator and starter. Such a device will also be used to allow the engine to shut off while the vehile is stopped, and power it back up instantly when needed. It's very similar in operation to Honda's IMA (Integrated Motor Assist) on the Insight and Civic Hybrid.
- Parasitic ancillary devices can be eliminated from the engine. The water pump can be driven electrically, and can be speed-regulated to allow the engine to operate at a more efficient temperature. The thermostat can be electrically heated (such a device is currently used on the VW Passat W8, but it will see more mainstream applications) to regulate flow through the radiator to achieve that result, as well. The power steering pump can be eliminated and an electric motor can be used to provide assistance, as well an infinitely simpler variable assist steering sytem. The A/C compressor can be electrically powered, instead of engine-driven, as well. Variations of these components are used, in one form or another, on production cars now, but can be made smaller, cheaper, and more efficient with the introduction of 42V systems.
Don't forget that 42V systems allow the use of electrically heated catalysts which reach operating temperature far faster than traditional cats that rely on exhaust gas to warm up.
Are they going to change the cigarette-lighter plug and all obey the same standard? I can picture it now... "I plugged in my cell phone to charge, and then it started smoking....." I already need a hundred 12-volt adapters in my house for charging different things, don't need them in my car as well.
Peugeot 307. They didn't go full-multiplex, but a sizeable portion of the electric doodads is basically doing things the USB way: a pair of power supply rails, and a data bus through the whole car. Cheap terminal gizmos in front of each device to demultiplex. VoilÃ, less wiring.
On the other hand, they could just go with the inelegant solution of designing an interface that makes it impossible to connect jumper cables.
We had to boost one of our cars the other day, and the only other vehicle handy was my father's Montana. The battery is in there in such a way that you cannot access the terminals directly, at least not without cutting away parts of the frame (or removing the battery, of course). To allow for boosts TO the van, they have a 'remote positive terminal' which you can easily access.
Only problem is, there is no 'remote negative terminal', essentially making it impossible to use his van to boost another car. Even the owner's manual insists you need a negative terminal to boost from, so it's not like there's some weird configuration of booster cables that I've never heard of.
Gotta love progress.
Endless arguments over trivial contradictions in books written by ignorant savages to explain thunder in the dark.
W-e-l-l if you've looked into the literature on turbocharging, you'd find that back pressure isn't usually a problem (unless it gets really high). The Wright R-3350 turbo compounds got about 20% more power by coupling the exhaust turbines through a fluid clutch. The idea is that there is a lot of wasted kinetic energy is the exhaust of a non-turbo'ed piston engine.
A Shadeless room is a brighter room.
the speed of sound used to be thought of as a natural ceiling.
when religion is no longer the opiate of the masses, governments will resort to real opiates.
42V is enough to pass through dirty water, so I anticipate all kinds of problems when things get wet, unless everything is carefully designed to tolerate some electrical leakage. On the contrary, a 12V motor will actually run underwater with no sealing!
When I am king, you will be first against the wall.
For electronics that a consumer can contact, the voltage still needs to be limited. With lots of grounded metal nearby, doing auto wireing is kinda like wireing your house circuit breaker panel while standing in a puddle in bare feet. It's not a great idea at high voltage.
.25 hoursepower and in the 12 volt example it's about 5.3 horsepower gone to heat.
This means that for a given efficiensy, the wieght of the wiring is proportional to the square of the current. I.e. Twice the current needs 4 times the copper.
Anybody want to take a stab at figuring wire sizes for a 1 volt drop in two examples below? If you do, figure a wireing length from battery to comverter (AC Variable frequency, variable voltage) to engine alternator/startermotor to drive motor, regenerative braking loop of about 15 feet. (7 feet each conductor + & -)
Anyway, the Toyota Prius uses a 300 volt battery for the electric drivetrain end of things. That keeps the wire sizes reasonable. For compatibility, it uses a converter to keep up a 12 volt battery (motorbike sized) for the lights, computer, instermentation, etc. The battery is small because it is not used to crank the engine. The 300 volt does it. If they dropped the voltage by 10, the current required to do the same job would go up by a factor of 10. Therefore a motor instead of running 200A at 300 volts would run 2,000A at 30 volts, or (ready for the 12 volt system) 4,000 Amps at 15 volts.
Here is where the big losses in low voltage systems come from. Drop 1 volt in the 15 volt system due to 4000 amps in a very large wire and your loss is 4,000 Watts. Can you say hot wires! Drop 1 volt on the 300 volt line at 200A on a much smaller wire and the loss is only 200 Watts. You can use a much smaller wire to get a better job done.
At 746 watts per horsepower, the loss in the 300 volt example is about
Driving a Toyota Prius is an experiance. It has the get up and go of a V6 even though it's a 1 Liter 4 cylinder engine. It gets it's merge to the freeway with a combination of gas and battery power. The engine auto shuts off for stoplights (restarts as you take off again) Other than the silence at a stop sign or light, you would never know the engine shut off. Because of this, it gets better milage in stop and go city traffic than freeway driving with it's high wind resistance. These would be fantastic for a fleet of taxies.
The truth shall set you free!
Right now nearly every add on in a car (radio, cell charger, that sort of thing) uses a version of the 7805 or 7812 regulator. These devices can cope with voltages up to 40V and thats considered reasonable based on surges on a 12 v system. With a 42V system, that already exceeds the input voltage of most low cost voltage regualtors and when you figure in for surges at 3x, its outside of all the low cost DC regulators. The resut is a part that is now a single 5 volt regulator may need a swtiching power supply until someone comes up with a 7812 style device that can cope with the much higher voltages.