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What Volts? - Stuart B
I think I have read somewhere that there is a new standard voltage proposed for car electrical systems of 42V.

The reason being that cars have so much gubbins on them today, especially if you take into account new catalysts and kit to deal with particulates that 12V systems just will not be practical.

Was it a dream?
Re: What Volts? - mike harvey
Stuart,
I had thought it was 48v, but it's close enough. Reason is to reduce weight of loom, as at 48v the current will be a quarter of the 12v system, and therefore the wires can be thinner and lighter. This also applies to the alternator and starter motor. Remember Ohm's Law? V=IR . I understand the current problem is persuading bulb manufacturers to produce 48v bulbs- they have a vested interest in maintaining the status quo. 48v is chosen to go as high as possible without the risk of electric shock. Apparently you need 50v plus for that.
Couple this with multiplexing and optical technology, and wiring looms will consist of next to nothing. I seem to recall that a loom weighs about 30 kilos , or is that pounds?
Regards,
Mike
Re: What Volts? - Ian Cook
Anything between 75v and 1500v DC would be classed as a hazardous voltge and must comply with European Low Voltage Directive 73/23/EEC. Likewise voltages between 50v and 1000v AC come under the same regulations.

Although wiring is OK at 48v DC the alternator, which produces 3 phase AC, could be a safety issue because it would push out more than 50v AC before rectification (to keep a 48V battery charged).
Re: What Volts? - Michael
that make sense, the telephone network is built around 50v supplies. Gives you a tingle if you touch the +/- wires with your fingers though. Ask any gpo apprentice!
Re: What Volts? - John Slaughter
Stuart

No, not a dream - there was an article on this about a year ago in the IMechE Journal.

Benefits are reduced currents,hence reduced losses, and reduced cable sizes.

Regards

John
What Volts? - David Lacey
It has been set to 42V, apparently. Or so I am reliably informed.

David
Re: What Volts? - steve paterson
An interesting, informative thread. Not many about these days !
Re: What Volts? - Andrew Hamilton
I remember some vehicles have 24V systems and got the impression that replacement parts were expensive as demand was low. If you go up to 50V any shorts due to wiring failure will be quite noticeable! I think Fords will not be the first to try it out!
Re: What Volts? - John Davis
Personally, I can't wait but, is it SO long ago that I thankfully got rid of my E93A Ford Prefect with it's puny six volt electrics and handle assisted starting ? How proud I was of my series 2 Morris Minor and the dramatic changes which it's 12 volt electrical system brought about. The reassuring click of the petrol pump, windsceen wipers which worked when you went uphill, and headlights which actually showed up a little bit of the road in front. With that latest technology, I thought I had really arrived but now it seems there is to be another leap forward. Is my social standing to be jeopardised again ?
Re: What Volts? - Andrew Smith
If you find any of the recent articles about the new BMW 7 series then I believe that this is the first car to have such an electrical system.
 

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