12 Volt Auto Power Headed for 36 Volts

It appears that automotive electrical systems will be going to 42VDC (36 volt batteries, 42 volt charging systems).
Details can be found on a popular Car Audio website: http://www.caraudiomag.com/specialfeatures/0307cae_42volt/

Once the new standards are adopted it should make powering QRO equipment mobile a lot easier.

73s de Tim KD7JZ

 

For the adventurous among us, now is the time to come out with the voltage reducers/regulators for all the 12 vdc accessories that are there and will be there for a long time to come.

K2WH

 

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

 

</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.

 

remember that we have been using higher dc voltages in trucks, boats and aircraft for years. When was the last time you read about someone getting killed with the higher voltages? how about your house wiring? it is more dangerous than anything we deal with each day. 73, Paul K4AVU

 

It's better than going to 6 volts, I guess.

 

I'm going to paly devil's advocate here, and no, I don't need any flames, but I think this is jumping the gun by at least a few years.
It appears that there is a new standard that will be implemented, eventually. But even the Car Audio article pointed out that the first vehicle to offer the 36V system will be a GM hybrid, not a purely conventionally powered vehicle. And the article's enthusiasm was particularly focused on how this will impact the Car Audio indistry.
But a few points/questions:

1. The statement that a higher voltage will make autos cleaner-burning and more fuel efficient. How exactly? Will there really be a significant reduction in weight to have an impact?

2. More powerful Car Audio amps will be built, and be less expensive... Just what we need! More "Past the threshold of pain from three blocks away" autos on the road.

3. More powerful amplifiers can be built into single unit dash mount radios. WELL, 100 W. of sound per channel STILL has to be dissipated, whether it's created at 12 V. or 36 V. If you can't dissipate the power at 12 V. in a small unit, you won't be able to do it with 36V.

4. The first vehicles will most likely carry 12 V AND 36 Volt batteries. GREAT idea. You put in a regular 12 V. battery and ADD the expense of the 36 volt battery. I can see the $$ in the auto maker's eyes.

5. The rticle sites GPS, DVD, cell phones, etc. as needing the higher voltage to operate. That's funny; all those devices "I" own run on four or less AA batteries. What happens to the other 30 volts?

6. The mention is made of the problem of voltage sags affecting performance, and possible spike damage. While voltage sag may be less of a problem, I don't see why spike damage would be any less of a danger.

7. Do we REALLY want our autos to be "drive by wire" and "brake by wire?" That's fine for aircraft, very expensive aircraft, but the quality control of autos is not the same as aircraft! Aircraft get frequent inspections, frequent overhauls. Would you want your car to have weekly or even monthly mandatory maintenance overhauls and inspections? 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? (I can see it now. I'm sorry, officer. My battery died without warning, and my brake-by-wire system didn't function. I couldn't help rear-ending your police cruiser...)

8. The statement that a higher (36) voltage system in and of itself provides for 110V outlets. (That's a great trick!) Certainly inverters are available for 12V to 110V, but I don't quite understand how that would be automatically provided by the 36 Volt system. Perhaps I misunderstood something in that point, or some thing was left out.

Again, it's all IMHO, but I think some of the questions are valid, and I look forward to serious, logical comments. It may help clear things up for myself and others.

I think it's a bit too early to order those 40 Amp. 36 Volt-to-12 Volt Step-down regulators, but it may not be too soon to start designing them! It appears the switch IS inevitable, but while not painless, it will be a graduated introduction.

 

Typical aircraft systems are either 28VDC or 115v/400cps AC. The AC hurts...especially at 400 cps.

73

Bill, WØLPQ
Collins Field Service, Retired

 

Think of the money the auto manufacturers will save on copper wire. When you triple the voltage you only need 1/3 of the wire size for the same wattage. Add this up for the millions of cars they sell and comes to a nice piece of change in their pockets.

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.

If this happens sure is going to be hard to get a jump unless someone else has a 36v system.

I remember when my dad bought a car in the 50's the first year the 12v systems came out. He must of had a bad battery as within 2 weeks of ownership it died in a food store parking lot, and my mother complaining about her ice cream melting.

He tried like crazy to get a jump and everyone had 6 volt systems. Luckily back in the golden days you could push start automatics, so this gentleman in a 52 Chevy pushed
us down the road at 35 mph and got the car running.

I was just a tyke then but remember it.

 

From what I've read about the higher voltage aukto systems, it is mainly for cranking and operating the vehicle. The 12 v will still be present and distributed. The 36/42/48 (depending on who's talking) will be used in a multiplex system to nodes with 12 volt outputs for external items like radios, etc. The higher voltage wires will be used to reduce the conductor sizes for weight savings (and less money for smaller wire). They'll find a way to charge you more for it, though.
Remember that many kv's are present going to spark plugs, so HV has been in auto circuits a long time.
I guess Jimmy Buffett will have to remix "12-Volt Man."

de WA4JA

 

I heard about this from my son 2 yrs ago. 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. (as well as the before mentioned reasons)
ecu-electronic control unit.
Len

 

Dang Homer,, dagnab thang startin all over again...
Frist ohhh noooo, 6V wasn't good enough,, we gots tas change evea thang ta 12V...
Now them folks want ta up the voltage ta 36 volts ??
Will it ever end?
On the other hand, higher voltages will allow for lighter, more powerful
motors, ( like windows, starters, actuators)
I remember back when some cars were 6v, seemed almost useless compaired to a 12v system..
as to shock hazzard, it's still DC and below 60V.
I know my icom with the 24V finals werks real gud..
I for one, welcome the change.
Dan kb7uxe.

 

Bill (W0LPQ)

Didn't you mean to say that the 115 Volts HERTZ at 400 CPS? <grin>

I still have my 7034 kc/s crystal from Novice days.

 

I don't think the new voltage is going to be that bad. There is going to be a transition period, and it may be really slow.

The motors and solenoids will not be less expensive. Yes, the wire size will be smaller, but there will be 3 times the length to make up for it. (impedence is higher) The real bennefit to automakers is the wiring in between the device and the power rails.

As far as car stereo goes, 40V supply rails, even in an H bridged configuration is still not going to be enough power for the people that like to blast their stereos to the point of mass annoyance and personal ear bleed levels.

 

I remember when all cars had 6 volt systems. When the engine is very cold the 6 volt starter motor required up to 800 amps to crank the engine. About half of the energy was lost in the battery/starter cable during starting. When they changed to 12 volts they still used the 6 volt ignition coil with a dropping resistor. In fact the 6 volt ignition coil continued to be used like this until recently. The resistor was bypassed during cranking appling 12 volts to the coil to give maximum spark for easier starting.

Two new products were in demand when this transiton took place. DC to DC converters to change 6 volts to 12, and dropping resistors to allow 6 volt items to be used in the 12 volt cars.

As for higher voltages in newer cars, 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.