42-Volt Autos 619
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."
Oh great (Score:2, Interesting)
For those unfortunate times... (Score:5, Interesting)
Great, more cr*p in the atmosphere... (Score:3, Interesting)
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.
110 Volts? (Score:1, Interesting)
If 36V is better than 12V, 230V surely must be better than 110.
dang, I need a jumpstart... (Score:5, Interesting)
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.
Ummmm... (Score:2, Interesting)
No more car tinkering... (Score:2, Interesting)
42 vols can kill you though - it can easily jump across wet skin.
Saw this one coming when.. (Score:5, Interesting)
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....
self sustaining arcs (Score:2, Interesting)
This is a good thing. (Score:5, Interesting)
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.
Re:That's bollocks (Score:2, Interesting)
- 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.
Re:Ummmm... (Score:1, Interesting)
Feel free to correct me if I made any mistakes... my electronics is a bit rusty after all these years.
Connector (Score:2, Interesting)
Re:For those unfortunate times... (Score:3, Interesting)
My guess is that most 36/42 volt cars will have xenon-arc HID lamps. The retail cost on those has gone from $5K - $500 in a very short period of time and will probably keep dropping. A typical Kia may never have HIDs, but most cars probably will. Now if only folks will keep their damned lenses clean and reflectors balanced to cut down on the glare!
There are a lot of other parts that will have to change with the times soon, such as all of the little motors (blowers, seat motors, trunk/door closers, etc).
multiplexed buses (Score:2, Interesting)
Re:Ummmm... (Score:2, Interesting)
Exactly. Thing is, more car speakers are 4-ohms, which means you can only get 9 watts peaks (6V^2/4ohms, cause the speaker will be virtually grounded in the middle of the supply) or 4.5W RMS with a single 12V supply. To get more power, you need a circuit to step up the voltage. With a 42V supply, you can get 110W peak, 55w RMS. A clean DC-DC voltage circuit is a significant cost of a car amplifier. You could decrease the effective resistance of the voice coil, but building an amplifier with sufficiently low output impedence is tough.
My father's Minivan already has this (Score:3, Interesting)
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.
Re:Not a EE, car nut or ME, but... (Score:3, Interesting)
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.
Re:No more car tinkering... (Score:3, Interesting)
Remember the old saw: "it's the volts that jolts, but the mills that kills".
42 volts will make you jump - I work in the telecomms industry and know what 48 feels like - but you would have to take some care to get enough current from a 42 volt supply through your heart to kill you. It would be a terribly inefficient way to commit suicide. Electric chairs typically use about 2000 volts [hypertextbook.com] Amazing (and kinda sad) what you can find with Google!
...laura
Re:That would be a natural ceiling (Score:4, Interesting)
Short circuits? (Score:4, Interesting)
Re:Hybred Voltage (Score:3, Interesting)
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.
42V will result in more dead electrical devices (Score:4, Interesting)
Re:42V will result in more dead electrical devices (Score:3, Interesting)