12 Volt Auto Power Headed for 36 Volts

I work in the electronics industry, and drive my own electric vehicle.  I thought WA9SVD had some valid points and questions regarding 42V automotive systems:


> 1. The statement that a higher voltage will make autos
> cleaner-burning and more fuel efficient.  
> How exactly?  

By allowing the use of electrically driven valves instead of a camshaft.  By doing so you can make the engine efficient by optimizing the valve timing over the entire RPM range of the engine.  By using the 42V ISA (Integrated Starter Alternator) the engine can start and stop in an instant, allowing the car to be shut off when stopped, and start instantly again.  This improves economy by not wasting fuel while stopped.


> Will there really be a significant reduction in weight
> to have an impact?  

No.


> 3.  More powerful amplifiers can be built into single
> unit dash mount radios.  If you can't dissipate the
> power  at 12 V. in a small unit, you won't be able to
> do it with 36V.

That may be true if you're running an 'analog' bipolar amplifier, but many are Class D and are very efficient, 85% or more.


> The first vehicles will most likely carry 12 V AND 36
> Volt batteries.

True.


>  I can see the $$ in the auto maker's eyes.

Believe me, they're not getting rich by doing so.  This is only to provide a "bridge" until their suppliers can begin to supply 42V systems.  There's a lot of inertia in the  automotive market, you can't just change gears in the middle of things.  After a period of years, the 12V battery will be gone.  In it's place, an inverter for user  accessories.  Then, in time, that will disappear too.  


> The article sites GPS, DVD, cell phones, etc. as needing
> the higher voltage to operate.  

It would be more accurate to state "higher power".  People want to plug in anything imaginable into their cars to charge and/or operate.  The 1kW or so a current 12V system has doesn't cut it anymore.


>  Do we REALLY want our autos to be "drive by wire" and
> "brake by wire?"  ... the quality control of autos is
> not the same as aircraft!

I've driven a car with brake by wire, you can't tell any difference.  The components industries are developing sensors with built-in redundancy and fault detection.  The computer will know and report failing sensors, and will likely prevent you from starting the car if there is a failure. The parts will undergo stringent life testing way beyond what they'd see in actual use. There is improved economy with these systems as they allow simpler chassis implementation, and lighter weight.


>  If a common problem  were found in a certain model,
> would you want your vehicle to be "grounded" until it
> could be inspected and repaired?  

That happens already.  Can you say "Firestone tires"?


> My battery died without warning, and my brake-by-wire
> system didn't function.  I couldn't help rear-ending
> your police cruiser...)

Batteries can die without warning, but a lot of other systems would have to fail at the same time for such a catastrophic event to occur.  Such that losing the brake by wire system would be the least of your worries.


> inverters are available for 12V to 110V, but I don't
> quite understand how that would be automatically
> provided by the 36 Volt system.  

I agree, I think the point here is that now there's some overhead in the system that allows energy to be diverted to a 120V inverter.


> I think it's a bit too early to order those 40 Amp.
> 36 Volt-to-12 Volt Step-down regulators,

Quite likely they will be OEM equipment with the car.


> It appears the switch IS inevitable, but while not
> painless, it will be a graduated introduction.

True.  High-end models with bigger sales margins will be first, when the technology becomes more refined it will trickle down to lower end models.  The next step is motor drives, similar to the Toyota Prius.  Load leveling, especially on the 3-ton rolling living rooms Americans like to drive, makes a big impact on economy.  Pretty soon your Ford Excursion or Cadillac Escalade will be more like a diesel-electric train, using a motive power plant and electric motor drive. Then, the next logical step is to replace the combustion plant for chemical, AKA fuel cell. That's *way* down the road, if ever.  Computers are making combustion engines more efficient all the time, it will be tough to come up with a non-fossil system that can compete dollar per watt/HP.


Others wrote:

> 36 Volts? And over 40 volts charging? Sounds very
> dangerous to me

Anything under 48V is virtually harmless.  If you have sensitive skin you may feel discomfort if you held electrodes with 48V on your skin, but otherwise there's no risk.


> Think of the money the auto manufacturers will save
> on copper wire.

This is one of the primary motivators.


> Will there be batteries with 18 cells ? Now your odds
> are 3 times greater of having a cell go bad, and one
> bad cell can prevent the vehicle from starting.

True, but these will not be your basic 12V flooded maintenance free Die Hard either. They will be sealed gel electrolyte batteries, like the Optima units.  The computer will control it's charge and discharge, and through algorithms already well understood it will detect when the battery is degrading.  You will know when to replace it long before it would fail on you.


> sure is going to be hard to get a jump unless someone
> else has a 36v system

The car won't let that happen, at least if it has anything to say about it.  It will automatically shut off interior lights if a door is left open too long (my current car does that), the headlights automatically turn off, and if it detects a situation where the primary battery is draining below what it will take to start, will turn off systems to make sure there is enough remaining energy to get the car started.


> The major reason is the ECU for the car can run at a
> faster clock speed thus  react to RPM, throttle position
> etc better  to work more efficently.

This is patently wrong, it has nothing to do with the ECU.  Clock/sample speeds in current cars are such that the computer will tell you what velocity the connecting rods are moving, and which spark plugs have a higher impedance than others.


> hybrids and EVs  have 144 volt to 288 volt systems for
> the  auxilary( in the hybrid ) electric motor.  The
> Honda  hybrids uses 144 volts and Toyota uses
> 273.6-volts.  These are lethal voltages.

No, they use these high voltages for the traction motor.  The auxilliary systems (as they stand today) use standard 14.2VDC.   Yes, they are lethal, but are completely shielded from the user by double insulation and tamper protection.  Funny how some are concerned about "lethal" voltages in EV's and Hybrids, but no one mentions the hazard of having 20 gallons of gasoline in their garage.  I much prefer my EV in the garage, no odors or explosion hazard there.

Good topic, it's only a matter of time before hams figure out a way to use the 42V systems to their advantage.

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (KE6QCV @ June 16 2003,12:31)</td></tr><tr><td id="QUOTE">36 Volts? And over 40 volts charging? Sounds very dangerous to me[/QUOTE]<span id='postcolor'>
That's nothing !  I once touched a 1000 ohm circuit in the rain....and lived !!

< ducking >

 

As far as voltage being lethal, 12 volts, applied through the right circuits can be more lethal than you can imagine. When you see a paramedic defibrillating (shocking) a cardiac arrest patient, 12 volt batteries are providing the juice.

73.

Chris Wilkie
W1LKE

 

Well This is an interesting thread. In my personal opinion though, I hope that they stay with 12 volt systems. I know I will not buy a new car/truck with anything but. As it is I cannot stand the new vehicles. give me the old fashioned normally aspirated, carburated, computerless, manual window/lock, no airbag, basic vehicle. I do not like current designs...some of the exterior streamlining is ok, but wy would someone need wind tunnel designed interiors. Rounded corners, and oodles of plastic, vinyl, and padding may make a vehicle safer if one is moved around inside of it, but it makes it hard to mount anything in a decent way inside the vehicle..ie radio & aftermarket accessories. Those sculptures inside also prevent a lot of movement when trying to do various chores inside the car like mounting these accessories, changing fuses, etc... As far as the automakers getting richer off the proposed new systems...why would they want to make less money? The extra components for dropping voltages are going to make up for the savings in wire I would think. Also look at the cost of new vehicle replacement parts: a new alternator for say a 1988 or newer vehicle runs in the LOW neghborhood of $125...and it goes up from there. my alternators for the vehicles I have are average $30 a pop. The same with starters. Fuel pumps in the new cars are running in the neighborhood of $80 or so...add that to the cost of a fuel pump relay..etc.... Mechanical fuel pumps work just fine thank you. The electrical drain on the new cars also is a pain with all the injectors needing voltage to run the car. The battery will die in a lot of cases from one's house to the parts store to get a new one because the injectors need that juice. If I get the car running, I can disconnect the battery and run it...unless it is at night where the lights will drain the system. Also if we want to run a lot of our radio equipment in the cars nowadays, it is almost inevitable that the RF will interact with the wiring and computers that the the vehicle employs. I know we get ignition noise and alternator whine on any vehicle, but I don't have to worry about a high watt amplifier toasting the computer system in a car that does not have a computer system. Labor costs are going up constantly and it takes more time now and costs more in parts when a vehicle breaks down. I for one will not buy a new vehicle. I will always buy used, and preferably the good ones I can work on myself without having specialized equipment or stupid proceedures to actually get the work done. Ever try to change spark plugs on some new front wheel drive cars? the engine literally has to be rotated to do so for the back 6 on the V6's. I can change all 8 on my truck in about 15 minutes. For those that think that 36 volts is going to be a blessing and produce a better and cheaper (cheaply made more likely) car guess again. As far as being more fuel efficient...hell, the gas mileage has not improved much at all over the years. AT ALL!!!! we are still getting the same gas mileage with the new cars that we were getting decades ago. Unless we want to go with a vapor carburator that some genius came up with way long time ago and produced 50-100 miles/gallon...The oil companies are not going to want the cars to be more efficient. As far as pollution goes, they have done comparisons, and some of the older vehicles (pre 1985) are getting better emission ratings than some of the new ones right off the lot. 36 volt systems??? I hope not. the only way it is going to possibly benifit us as amateur operators is where one has to run higher DC voltages to activate a VHF amplifier/switching network as in rover operations with masthead preamp relays as a lot of those are running upwards of 28 V....though one can run a dual battery system in a car and run a circuit that taps both batteries into a series which would not only power the preamp relays and 600W 2 meter amps, but would also run, in the parallel standard in the car, with a higher reserve of power so ones lights do not dim when keying up. But again, this is in my honest personal opinion...and many of you might take a different view.

Dave.....N9TTX

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (ka8ncr @ June 16 2003,06:56)</td></tr><tr><td id="QUOTE"></span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (KE6QCV @ June 16 2003,12:31)</td></tr><tr><td id="QUOTE">36 Volts? And over 40 volts charging? Sounds very dangerous to me, something for all to remember is that 30 volts DC at 1 Milli Amp can kill under the right conditions. (Live electrical circuit contacting the left hand or arm and exiting anywhere below the heart) Someone jump starting the car in the rain would be a good candidate for the morgue if things went bad and he grabbed the end of the wrong cable, or someone setting up their first radio and held on to the bare end of a wire going to the voltage converter while plugging it into the fuse box would also qualify. (MMM GFI breakers for DC sounds like a good idea to me)


73's and be careful out there

Terry[/QUOTE]<span id='postcolor'>
You better not touch your landline phone circuit then; the battery on that is 40 volts.[/QUOTE]<span id='postcolor'>
Actually 48vdc

 Oh my God! even worse

 

Dave N9TTX wrote:


> give me the old fashioned normally aspirated, carburated,
> computerless, manual window/lock, no airbag, basic vehicle.  

I don't agree, I think cars have gotten much better, especially during the past half dozen years or so, despite the added complexity.  If the "old" cars were really better, they would still be built that way.  Those "old" cars you cite as being so great were "new" cars at one time, and were just as mystifying to potential car buyers as "new" cars are today.  In fact, I'd take a 2000 over a 1985 any day, 80's cars had vacuum systems from hell, tons of stupid little vacuum motors flipping flappers and levers, hacked in emission controls and too many new gasket and seal compounds that didn't stand the test of time.


> I do not like current designs...makes it hard to mount anything in a
> decent way inside the vehicle..ie radio & aftermarket accessories.

Somehow I don't think they have the ham community in mind when designing dashboards.    Where there's a will (and a drill), there's a way.  I haven't been stumped yet.


> The extra components  for dropping voltages are going to make up for
> the savings in wire I would think.  

The added components aren't necessarily there for the sole purpose of reducing wire size.  They typically add functionality in some other way which provides additional benefits.


> look at the cost of new vehicle replacement parts:
> alternators ... Fuel pumps

The likelihood is that these parts will never need to be replaced for the life of the car.  I remember with some of my older cars, getting the NAPA "lifetime" starter or alternator was a wise choice.  The past few cars I've had I've never had an issue with these items failing, ever.


> if we want to run a lot of our radio equipment in the cars nowadays,
> it is almost inevitable that the RF will interact with the wiring and computers

That may be true in rare cases, but understand that susceptibility is a design criteria in these systems.  They need to be robust enough to operate in just about any environment you can imagine, including co-located RF sources.  Most often in these cases, simple grounding/bonding/ferrites and selective cable routing will take care of the problem.  (I used to install 2-way radios for a living...)


> takes more time now and costs more in parts when a vehicle breaks down.  

The likelihood is that it won't break.  Yes, the parts are more expensive, but over the life of the car the overall costs are low.  A $200 fuel pump sounds like a lot but if it's the only failure you have, you come out ahead.


> I will always buy used, and preferably the good ones I can work
> on myself without having specialized equipment or stupid proceedures
> to actually get the work done.  

Have you ever worked on an OBDII car?  It's a breeze.  Even the old OBDI car I had made it really easy to troubleshoot and fix, the few times I actually had a problem.  Yes, you have to buy a book, own (or borrow) the interface, but after that you just jack in and see where the trouble is.  Most folks aren't going to bother to learn or understand their cars, so then they're bound to being dependent on the (expensive) dealer.  The tools and information are there, you just need to learn it just like anything else.  Shouldn't cars benefit from technological advances just as much as say, the PC you're reading this on?  Don't see too many folks complaining about how much better their 486 Windoze 3.1 machine was than their new Pentium.


> Ever try to change spark plugs on some new front wheel drive cars?  

Shouldn't have to.  They should last the life of the engine, even the manufacturers warrant them to 100K miles on some cars.  The ignitions are continuously adjusted for optimum fire, fuel injection systems don't foul plugs like carburetors can, and plug electrodes are tough enough to wear slowly.


> For those that think that 36 volts is going to be a blessing and produce
> a better and cheaper (cheaply made more likely) car guess again.  

Would your opinion change if you paid the same for that car, but over the period of time you owned it you saved money on fuel, maintenance and repairs?  It's one thing if you like to tinker with old cars, but I'd rather be working a 6M opening than on the family sedan.  Infrequent repairs or maintenance is an added value in my opinion.


> gas mileage has not improved much at all over the years.  AT ALL!!!!  

You're dead wrong there.  You have to compare apples to apples when it comes to displacment, power and vehicle weight.  Consider that 10 or 15 years ago a 5000lb SUV-type vehicle might've gotten 9MPG, now they're in the teens.  You've got 200+HP V6's with much improved efficiency in cars that used to have a 150HP V8.  What might make you think economy hasn't gotten better is say an "old" pickup which had a V6 that got 18 miles a gallon, and with the "new" pickup it may get worse mileage but now it has a V8 and 1.5x the HP.


> go with a vapor carburator... produced 50-100 miles/gallon...

Urban legend, they never existed.


> The oil companies are not going to want the cars to be more efficient.  

Perhaps not, but the government sure does.  Who do you think is putting constant pressure on OEM's to increase fuel economy?  It isn't the consumer, if it was up to most people they'd be content with the cars of the 70's.  Car makers are constantly coaxing every last bit of efficiency out of each facet of car dynamics, from aerodynamic shape, to advanced lubricants, to low rolling resistance tires.  Anything they can do to eek out that last bit of efficiency to squeak by the DOT standard, which is ever increasing.


> some of  the older vehicles (pre 1985) are getting better emission
> ratings than some of the new ones right off the lot.  

I don't believe that, but even if it were true under specific circumstances there would be no way a normally aspirated, non computer controlled engine can beat a modern car under all conditions of RPM, load and temperature.  And that's the way they're judged, from cold start to freeway, not 25mph on a flat road on a warm day.


> the only way it is going to possibly benifit us as amateur operators is
> where one has to run higher DC voltages

If you think of it in terms of watts and not just volts it might be a little easier to understand.  Don't be concerned about what the actual ISA system voltage is running at, there will be converters that either you or the OEM will supply to do whatever you need.  Why not just have 120VAC available and be done with it?  Or, the "standard" 12V will be available for years to come.  What I'm seeing with most products these days is universal power input.  88-288V, AC or DC.  Plug it into a warm fuzzy and it works.  Switching power supply density and efficiency these days is pretty incredible, and prices are dropping all the time.  I have a switcher I use with my 706 that I can plug into a wall socket or the traction pack of my electric vehicle, no difference.  In my view, changing to a new vehicle power standard opens up more and better ways of doing things than being limited by the same 50 year old 12V, 750W negative ground system.  It's gonna happen, and I'm looking forward to it.

Mark K5LXP
Albuquerque, NM
k5lxp@arrl.net

 

===========================================================

> takes more time now and costs more in parts when a vehicle breaks down.

The likelihood is that it won't break. Yes, the parts are more expensive, but over the life of the car the overall costs are low. A $200 fuel pump sounds like a lot but if it's the only failure you have, you come out ahead.

========================================================================

WHOA! Let's get real here! There is no (or at least not much) reason to believe that a 36 Volt fuel pump would be any more reliable than a 12 Volt fuel pump. or any such auto peripheral! I had a 1984 D**SUN ( I won't mention the brand name) that had four electrical fuel pump failures, only the first two covered by warrantee or factory recall, in less than 90,000 miles. Is there any guarantee that a higher voltage system will "magically" ensure higher reliability? Particularly with newer, unproven designs for the new 36 V. standard?

 

> There is no (or at least not much) reason to believe
> that a 36 Volt fuel pump would be any more reliable
> than a 12 Volt fuel pump. ... I had a 1984 D**SUN

100% agreement.  My argument is that a fuel pump made in the last 5 years is going to be much more reliable than one built in 1984.  Fuel injection was relatively new then, processes and materials have advanced a lot in nearly 20 years.  The thread is kind of diverging away from 42V systems to cars in general, but overall I think cars have only improved and become more reliable as advanced technology has been introduced.  When I was a kid it was a pretty remarkable thing to have a car go over 100K miles without some form of major repair, now the benchmark is nearly twice that.  Yes, stuff happens and cars break down, but I don't spend nearly the time under the hood as I used to, on cars that have many more miles than they used to.

Mark K5LXP
Albuquerque, NM
k5lxp@arrl.net

 

Hot Dang! Now I can finally go install those 747 landing lights on my car!

 

Again playing devil's advocate, is there ANY reason to believe 36 Volt accessories, whether they be fuel pumps. braking systems, or whatever, will be more reliable than the same on a 12 Volt system? Based solely on the operating voltage, that is, and assuming an inordinate amount of power isn't required.)

 

*S*  Like I said it is my opinion...I may be a 36 year old fuddy duddy, but I personally hate the fuel injected BS nowadays.  One of my other hobbies is street rodding and I love to work on vehicles as long as they are not the "new" ones.  My 1975 1 ton dually 4 door pickup regualrily gets 15 MPG on the highway with a slightly modified engine.  Most of the people I work with have new injected engines in thier smaller trucks (1/2 and 3/4 ton) and are getting the same if only 2 MPG more.  Mine are paid for, theirs are not. The little repair I put into my vehicles is nothing compared with car payments.  If one of mine is beyond repair, I salvage parts and buy another older like vehicle.  The newer 88 VW I do have is going to be retired as it has seen a good healthy 250000 miles, but it needs more repairs than it is worth.  I prefer a K.I.S.S. car.  Many of those old "clunkers" will still outperform the new ones.  One BIG factor in why I like old cars is that there is more steel in the older ones...not that flimsy side panel stuff...or those rediculous 5 mph bumpers...who gets into an accident at only 5 mph?? Steel bumpers bolted to the frame...with Chrome might I add...Yeah!!!

But anyway, If they do decide they are going to 36V or whatever I hope it is beyond my lifetime.  Personally I think it is a mistake on the manufacturer's part.  Some people seem to think that they have to have their kitchen sink in the car or truck at all times to live right.  Me, I just want the radio to keep me company...and stacking various rigs in the car (RCI's, TS 120S, Kenwood, Rad Shack's) is a whole lot easier to do if the dash is square and made of steel, and they will power just beuatiful by running a nice hefty set of wires directly to the battery. That, and if one wants to drill holes all over to mount antennas and for bulkhead grommets/fittings, the dealership and next prospective buyer wont complain as much if it is done on one that has seen many moons.


     Flame away!  Dave...N9TTX    *LMAO*

 

SVD: Hertz rents cars. Have been using cps/mcs/kcs for over 50 years, yep an OF..! I use the new abbreviations to make new kids happy. My grandfather got me into using the old abbreviations, and even at age 10, told me that Mr. Hertz should get credit for his work. And, he eventually did.

This is an interesting thread. There are advantages to higher voltages. Some aircraft (Jetstream 31/41 series from the former British Aerospace (BAe), used series batteries (providing 48V) to do the engine start for their turbines. Faster rotation, quicker starting...! Once engine start occurred, then the batteries reverted (via relay contacts) back to parallel operation.

73

Bill, WØLPQ

 

Bill: Is it true 115 V. "Hertz" more at 400 cps than at 60 cps? <GRIN> I'm not fond of contact with either!
Yes, I also grew up with "Cycles per second." And I remember a lot of resistance to the change. (I guess change always "Hertz.") But probably a lot of the "young'uns" out there will not realize what "cps" means.

 

Let us see now: The series to paralel voltage system would need a switching relay and TWO diodes per cell (one to charge, one to discharge) to keep the drain on the batteries equal. Sort of like a diode bridge rectifier with a battery connected at each ac terminal.

Oh yes the old military jeeps were 24 volt- 2 12 volt batteries in series. At least the surplus one I rode in 1966-7 was.

Quadrupling the voltage to 48 volts means you can get 16 times the power through the same wire. Ohm's Law.

 

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (k5lxp @ June 17 2003,13:51)</td></tr><tr><td id="QUOTE">> some of  the older vehicles (pre 1985) are getting better emission
> ratings than some of the new ones right off the lot.  

I don't believe that, but even if it were true under specific circumstances there would be no way a normally aspirated, non computer controlled engine can beat a modern car under all conditions of RPM, load and temperature.  And that's the way they're judged, from cold start to freeway, not 25mph on a flat road on a warm day.[/QUOTE]<span id='postcolor'>
I am just going to pop in on this one real fast

I have seen this happen a couple times.
Texas has or Had, can't remember or keep up with how often they change those dag blasted emission laws round here.

I had a 1986 GMC half ton with a 350ci V8 tucked under it nicely (Yes I loved that truck )

I thought it was running a tad out of wack, but when I took it up on a fairly cool morning to have it tested, they got it up on the rollers, pushed it to whatever their limits were and the dang thing actually had emissions than that were lower than they needed, in a couple cases flat zero on certian typs, but all the tested ones were at least near dead bottom of the ranges they needed, and a newer car test about the same time, was a car with a V6 not another V8 truck, had levels that were still passing, but much higher into their respective ranges than my beast of burden had, to say i was happy was a slight understatement.

wel that is just my 2 cents