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."
good for the environment (Score:5, Informative)
Car manufacturers have said that it is more expensive for them if their product line has to have two different types of electrical systems. If high voltage electrical systems are going to be standard equipment, though, that argument will disappear.
110VAC outlets available today (Score:4, Informative)
One of the main advantages of the 42 volt system is that you can have electronic, rather then hydrolic brakes.
Re:Great, more cr*p in the atmosphere... (Score:2, Informative)
http://www.discover.com/may_03/featoil.html
hummers do (Score:5, Informative)
since some military trucks spend a lot of time sitting and not driving this happens more than you might wish to think
Re:No more car tinkering... (Score:5, Informative)
It's just that more current will flow with 42 volts than 12 volts -- 3.5 times as much.
Also, to kill you, the current needs to flow through your heart (unless it's a LOT more voltage, pushing enough current to start cooking your flesh.) This means that you'd have to touch each terminal with a hand.
I remember the 68 volt batteries that they used for old flourescent lights. Even getting your fingers wet you could barely feel the voltage with them, and not at all having each hand touch a terminal. (Yes, I was a curious kid.)
In short, I don't see how 42 volts is going to kill you. Even 110 volts has a hard time doing it.
Re:Some basic EE facts (Score:4, Informative)
I'm a blockhead.
That's bollocks (Score:5, Informative)
Where ? 12V lead/acid batteries have 6 elements, 42V batteries would have 21. That's 21 lead plates and associated acid cell. The only thing that would be lighter would wire harnesses, because the wires would be lower-gauge wiring since they wouldn't have to transport as much current. I can't see that being a real weight economy.
improve fuel economy
How ? do 42V alternators have a better efficiency than 12V ones ? And even if that was the case, wouldn't, say, driving the alternator with something else than a rubber belt improve efficiency much more dramatically ?
permit the replacement of many mechanical parts with electrical ones
How ? what are the mechanical parts that can't be replaced by 12V electrical equivalents that could be replaced by 42V ones ?
power all sorts of new gizmos like seat heaters, video, etc,
I can't wait to see cars with seat heaters or video units
and, of most concern to us, improve efficiency for all automotive electrical devices
I don't know about overall efficiency, but in all fairness, that's true : it's easier to step the voltage down than up. So yes, many devices would become lighter, cheaper and probably more efficient.
opening the door to higher audio amplifier power with far less complexity than the current crop of 12-volt, high-power amplifiers. Not only can will this translate to lower cost and more compact aftermarket power amps, even head units could cheaply integrate 100-plus RMS watts per channel power.
That's about the only application where I can see a 42V system be useful.
All I see in that "improvement" is trouble, exactly like when cars switched from 6V to 12V, and more money to aftermarket accessory makes. For many years, you'll have dual-voltage devices (complicated and defeating the purpose of having a higher voltage in the car) that will be more expensive and heavier, you'll have to buy another cell phone charger, power-supply, CB and whatnot, you'll have to use voltage converters, people without a clue will plug 12V devices in 42V cars, giving more money to garages,
In short, a half-load of technical shit, trouble for everybody and a lot of money for the automotive industry
Re:Great, more cr*p in the atmosphere... (Score:3, Informative)
A higher voltage on the line is a good thing because it means less current through the wires, which in turn means less losses across them. Oh, and less current through the entire system means it is easier to keep a proper ground level across the entire chassis.
Re:For those unfortunate times... (Score:5, Informative)
If the car companies had any brains, they would anticipate this problem. They could put some electronic thingy on the charging posts that automatically senses 12v and runs it through some power electronics to step it up to 42v. I don't know how efficient that would be.
Or, if the engine electrical system still runs on 12v (through a step-down), there could be a direct interface to the starter -- once the engine is started, the alternator takes over and charges the battery at 42v.
On the other hand, they could just go with the inelegant solution of designing an interface that makes it impossible to connect jumper cables. Then you would be in trouble.
42V is for steering, not audio (Score:5, Informative)
The 2004 Chevy Malibu will launch this fall with a 42V electrical system and Delphi E-Steer electrical power steering. It's not full steer-by-wire; there's still a mechanical linkage. But that's for backup, through a flexible coupling. The real steering is done with a sensor on the steering column, a motor in the steering box, and a computer watching speed, steering angle, skid information, and such.
This will make converting cars to computer control much easier.
Re:Great, more cr*p in the atmosphere... (Score:2, Informative)
Also people's stereos won't necessarily be louder, but the equiptment will be smaller, more efficient and cheaper to manufacture, thus saving money.
In my eyes, this can only be a good thing, but it's too bad we'll all have to wait until 2020 for complete conversion...
Re:No more car tinkering... (Score:4, Informative)
V = I * R, or re-arranged for what I'm going to show, I = V / R.
I measured my body's resistance using a multimeter, and usually got between 150Kohm and 200Kohm (hand to hand, going through my heart). Plugging this in for a 12V car battery, we get I = 12V / 150Kohm =
Re:For those unfortunate times... (Score:3, Informative)
safer, too..... (Score:2, Informative)
This is works, but it can cause fires if the high voltage system comes in contact with the low voltage one. Fires and high voltage systems in cars can be very nasty [wwltv.com]. This complicates the job of resuing people [firehouse.com] from an accident or repairing [asashop.org] the car afterwards.
Re:Oh great (Score:3, Informative)
Re:Bastards! (Score:4, Informative)
Changing Voltage CHanges nothing (Score:5, Informative)
I don't see how changing voltage will make cleaner sound. The biggest problem with mobile electronics is lack of a good ground. The ground on a modern vehicle sucks. When I run a HF radio in the car, most of the losses are because of the ground system in the car. It's near impossible to fix that properly. The antenna systems in the car are almost always verticals and normaly you'd either burial radials or have a decent ground plane built. With a car, it's impossible to change the width of your ground plane because it's mobile. Mobile installations almost always require an antenna tuner because of this and this is just to make sure your SWR stays radio safe. You may have a radio capable of 100 Watts, but I have never seen one produce it. Plus the alternator produces alot of hash that needs to be blanked out or filtered out. RF chokes on the power cords and other things to get rid of this noise. When you run off of just batteries, that noise is not there anymore and you don't need those filters.
Re:dang, I need a jumpstart... (Score:3, Informative)
Believe it or not, some of this is die to one of the few true current uses of "Nanotechnology", which is defined my most scientist as anything involving stuff hat has one dimension 1um
The use is in cutting tools. The industry has switch to all "insert carbide" cutting tools. The big advance in this is that the particles used to make these inserts to are smaller than 1um. This allows the cutting tool to be both hard and tough. This allows things like machining some parts pre-hardened and others at higher speed (which gives a better finish). Plus the cutting edges ware out much less often. This allows the tolerances of a machined part to be a lot tighter, which means that the average car coming out of the factory is much closer to "Nominal". That allows them to move the nominal design point closer to the part of the curve they want (Performance or economy, or whatever)
It's one of those places where materials science has really improved out lives
Re:No more car tinkering... (Score:4, Informative)
It is not that simple. As you apply higher voltage to your skin, its resistance will decrease very rapidly, and in the result the current flowing through your body will be much greater. And yes, 48V can kill you.
Safety (Score:3, Informative)
Re:That's bollocks (Score:3, Informative)
42v electrics makes it practical to throw around enough power to do things like:
1. Electrically operated valves can offer increaced flexibility in valve timing, allowing a broader efficiency band for the engine.
2. Electrically operated accessories mean that things like Airconditioning and power steering don't take more power than they need when operating at high RPMs
3. Starters and Alternators can be replaced by motor-generators which can be used to make hybrid-like features such as instant start (so you can cut the engine at stoplights), regenerative braking, and electrically assisted acceleration available broadly throughout a manufacturers model line.
12V electrics enabled such frivolous accessories as head and tail-lights that could actually be seen from more than 6 feet away.
Re:Bastards! (Score:3, Informative)
Where the power is (Score:3, Informative)
So the wire can be 1/3 the diameter. (Ignoring the fact that the smaller wire won't dissipate heat as well)
Re:Oh great (Score:1, Informative)
More environmentally friendly (Score:2, Informative)
Re:Ummmm... (Score:1, Informative)
Up to a point.. yes... but think about it... You've got to deliver X watts of power through a 4ohm speaker...
If you put 12V across 4ohms, you're delivering... (Remember I=V/R and P=IV...) 36Watts maximum...
You may have noticed that there's a lot of stereos with higher ratings that this... That's because they have internal voltage multipliers so that they can deliver a higher wattage.
>Homes have exponentially increased power comsumption, yet the answer has been higer amperage wiring, not extensive high-voltage circuits.
To use the hosepipe analogy...
AMPS tells you how thick the hosepipe(wire) has to be
VOLTS tells you how much water pressure you're getting.
The more pressure you use, the more water(electrons) get delivered.
That's why they use really high voltages (420,000V) for overhead cables... It's an efficient way of delivering megawatts of power without needing a cable the size of an oil drum.
Should be -2, Moronic (Score:3, Informative)
The luxury market does not drive any portion of the auto industry. It is the least profitable buisness segment. New tech appears in the luxury models only because that is the only economic way to proof it (beta testing). So the luxury lines provide a testbed for development, which justifies their existence. The auto industry does not ever develop tech that can not be applied across product lines.Doing so is not profitable
I have worked in the Automotive electronics industry, developing motor controlers, regulators, converters, etc. The 12V standard is the one single greatest impediment to the development of efficient electric/hybrid autos. A 12V motor will be at least 2 times the wieght of an equivilently powered 36V motor.
EMF (volts) != Power ( watts), idiot.
Higher voltage will result in smaller power supplies and more efficient systems. As a youngster, I use to maintain very high powered 12 volt electric equipment ( Power[P] = EMF[V] * Current[I] ( amps)
P = I^2 * Resitance[R] ( ohms)
R = Constant * Length / CrossSectionalArea[A]
(BTW this P is waste == inefficiency)
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.
Re:My father's Minivan already has this (Score:4, Informative)
The WAY you should boost a car is to connect positive battery terminal to positve battery terminal, then connect the negative to a part of the frame where there is no paint and you can get a good connection, away from the battery compartment.
If you absolutly must connect to the negative terminal (can't find a good ground), connect the most dangerous negative terminal first (most enclosed space, less water in battery etc). That way there will be no sparks near the dangerous battery.
Re:Bastards! (Score:3, Informative)
Bollocks *to you*, knucklehead... (Score:5, Informative)
Where ? 12V lead/acid batteries have 6 elements, 42V batteries would have 21. That's 21 lead plates and associated acid cell.
Get with the times. Upping the voltage allows the same punch with less current, which allows the use of smaller, lighter, NiMH batteries. Of course NiMH could be built in larger sizes, but they're not -- and being able to use smaller, commodity sizes is a hell of a lot cheaper. In fact the Honda Insight and Toyota Prius use commodity NiMH 'D' flashlight cells chained together in a big battery pack. 35 of these in series gives a 42V battery with more oomph than a stone-age lead-acid wet cell, is longer lived, more reliable, hardly affected by temperature, and a fraction of the weight. In case you haven't noticed, car batteries are *heavy.* Engineers love to be able to reduce vehicle weight, but the real savings is in shipping cost!
the wires would be lower-gauge wiring since they wouldn't have to transport as much current. I can't see that being a real weight economy.
No, but it sure is cheaper -- and more reliable. Higher voltage is less affected by bad grounds, corrosion, etc., which are the source of most vehicle electric problems.
improve fuel economy
How ? do 42V alternators have a better efficiency than 12V ones ? And even if that was the case, wouldn't, say, driving the alternator with something else than a rubber belt improve efficiency much more dramatically ?
Yes, higher voltage devices are more efficient. But besides that, the move is toward direct drive, combination, generator/starter/traction motors that live in the bellhousing like the one in the Honda hybrids. There's no belt, and no losses (or maintenance issues) due to that. There's one device, not two or three. It lives in a thermally stable, clean, dry environment. In ten years, more cars will have this hybrid-like architecture than not, whether or not they'll be true hybrids. It's simply a better way to build a car.
permit the replacement of many mechanical parts with electrical ones
How ? what are the mechanical parts that can't be replaced by 12V electrical equivalents that could be replaced by 42V ones ?
Electric air conditioning compressors, power steering and brake servos, etc., become viable with a higher voltage system. Higher voltage allows them to be smaller, lighter, cheaper, and efficient enough to surpass current technologies.
and, of most concern to us, improve efficiency for all automotive electrical devices
I don't know about overall efficiency, but in all fairness, that's true : it's easier to step the voltage down than up. So yes, many devices would become lighter, cheaper and probably more efficient.
Well if you don't know, then STFU. "I don't know what I'm talking about, but here I go anyway..."
And yes, many devices would become lighter, cheaper, and more efficient. A few watts here, a few watts there, it all adds up. A few dollars here, a few dollars there, that all adds up too -- except that automakers think in *fractions of pennies.*
opening the door to higher audio amplifier power with far less complexity than the current crop of 12-volt, high-power amplifiers. Not only can will this translate to lower cost and more compact aftermarket power amps, even head units could cheaply integrate 100-plus RMS watts per channel power.
That's about the only application where I can see a 42V system be useful.
I'm sure.
Voltage and Audio Amps (Score:2, Informative)
Re: dang, I need a jumpstart... (Score:3, Informative)
When you someday get a newer car (one that would have a 36/42 volt system), you'll find it has features to greatly reduce the chance you'll run your battery down... like automatic shutoff of the lights if you leave them on by mistake. Most newer cars have these features, and certainly any 42 volt cars in the near future would have it.
easier to get shocked from 36+ volts
42 volts is still very safe. Even in europe with stringent electrical safety standards, you need to be over 60 volts before heavier insulation is required.
easier for the electrical system to fry itself in a flood situation
If there is a flood that raises high enough to immerse your car that deeply in water, you'll have plenty of much worse problems to worry about.
Is it just me,
No, there are plenty of other people who resist any changes, no matter how well thought out and beneficial they may be.
is the automotive industry quickly moving to purely disposable/recycleable cars?
Not likely. Look at full service warranties, which are now often 50000 miles. That long was unheard of 15-20 years ago. Most modern cars do last longer.
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.
Probably even better, if the historical trend continues. Replacement parts will likely become even more specialized and expensive, and repair work may continue to require more and more specialized skills and equipment. But the truth is that cars have slowly but steadily improved over the last few decades.
Re:For those unfortunate times... (Score:3, Informative)
Losses are mostly related to the number of amps. So, given that you have a 12V battery, and require about 1.2 kW for the starter motor, you need about 100 amps. That requires hefty cables.
At 42V, that same 1.2kW starter motor requires only 29 amps.
If you want to be able to plug in an "old fashioned" 12V radio, a local step-down converter can be had pretty cheaply, and can convert 42 to 12 without trouble. This works the same way as your computer converts 5V or 12V to 1.2V for the CPU.
Which in fact is the same as your powersupply which converts the rectified 230 or 110 (320 or 154V respectively) to the 12V in the first place.
Oh, about 48V (4*12) screwing with a 42V battery... A 12V battery charges at 14 - 14.4 Volts. That would translate to 49 volts for a 42V battery.
Roger.
For serious information on 42V systems... (Score:2, Informative)
One advantage I haven't seen in any of the previous posts is that 42V provides enough power for components to be moved off of the serpentine belt and away from engine. The change from mechanically powered to electrically powered has the potential to drastically alter the design of automobiles by distributing components around the vehicle instead of everything being lumped together under the hood.